Renewable Energy Report

R E S O U R C E D E V E L O P M E N T / E N V I R O N M E N T & Q U A L I T Y S E C T I O N

The Potential for Renewable Energy Usage in Aquaculture

Damien Toner, Resource Development Section, Aquaculture Initiative

14 Grays Lane, Park St, Dundalk, Co. Louth Phone 042 9385074 • Fax 042 93 52490

Mo Mathies, Environment & Quality Section,

Bord Iascaigh Mhara Crofton Road, Dun Laoghaire, Co. Dublin

Phone 01 2144 100 • Fax 01 2144 119

FOREWORD

The Aquaculture Initiative is a dedicated support body, committed to playing a leading role in the development of a sustainable aquaculture industry throughout the Initiative’s remit area of Northern Ireland and the six border counties of the Republic. The team advises the aquaculture industry on financial, technical and strategic issues, in order to provide effective support to new and existing aquaculture ventures.

Bord Iascaigh Mhara, the Irish Sea Fisheries Board, was established under the Sea Fisheries Act 1952 as the state agency with primary responsibility for developing the Irish seafood sector. BIM’s aim is to promote the sustainable development of the Irish seafood industry at sea and ashore and support its diversification in the coastal regions.

This report, which has been published jointly by the AI Resource Development Section and BIM Environment & Quality Section, is a timely look at the potential for renewable energy usage in the aquaculture industry. We would like to thank Dr. Anthony Kay, University of Limerick, for reviewing this report. December 2002

Table of Contents

1 Introduction 1

Case study 2

Pacific Oyster Farm 2

Rainbow Trout Farm 3

Marine Recirc Unit 4

2 Energy Efficiency 5

Efficient Technology 5

Efficient Design and Planning 6

Efficient Purchasing & Maintenance of Equipment 6

3 Energy Loads 8

Fig 1.1 Energy Load of Pacific Oyster Farm 9

Fig 1.2 Energy Load of Rainbow Trout Farm 10

Fig 1.3 Energy Load of Marine Recirc Unit 11

4 Wind Power 13

Wind Turbines 13

European & Irish Production Overview 14

Fig 2.1 European Wind Energy Potential 15

Offshore Wind Energy 15

Small Scale Wind Turbine Systems 16

Basic Principles of Wind Power 16

Windspeed 17

Fig 2.2 Frequency of Wind Directions 18

Fig 2.3 Energy Output of Wind Turbines 19

Windpumps 21

5 Hydropower 24

Fig 3.1 Top Hydroelectric Producing Countries 25

Basic Principles of Hydropower 25

Micro-Hydro Systems 26

Ocean Energy 29

Water Powered Pumps 34

6. Solar Power 36

Solar Water Heating 36

Solar Electricity 38

7 Other Energy Sources 41

Bioenergy 41

Methane Digesters 43

Hydrogen Power 45

Geothermal Power 46

8 Environmental Considerations 47

9 Conclusion 49

10 Useful Contacts 51

1 T H E P O T E N T I A L F O R R E N E W A B L E E N E R G Y U S A G E I N A Q U A C U L T U R E

INTRODUCTION "Coal, gas and oil will not be the three kings of the energy world for ever. It is no longer folly to look up to the sun and wind, down into the sea's waves." The Economist

I n July 1996 the European Parliament adopted the Declaration of Madrid, calling for a major boost in the share of renewable energy in the European Union. The declaration states:

"In the year 2010, Renewable Energy Sources can, and with collaborative efforts between all actors should, substitute the equivalent of 15% of conventional primary energy demand in the European Union."

The process of looking at renewable energy started in 1992, when governments adopted the United Nations Framework Convention on Climate Change. They recognized that it could be a launching pad for stronger action in the future. By establishing an ongoing process of review, discussion, and information exchange, the Convention makes it possible to adopt additional commitments in response to changes in scientific understanding and in political will. In December 1997 some 10,000 delegates, observers and journalists participated in the conference on the Convention on Climate Change hosted by Kyoto, Japan. The high-profile event resulted in a consensus decision to adopt a Protocol under which industrialized countries will reduce their combined greenhouses gas emissions by at least 5% compared to 1990 levels by the period 2008-2012. This legally binding commitment promises to produce an historic reversal of the upward trend in emissions that started in these countries some 150 years ago. On 10 July 2002 Ireland joined the other EU member-states in formally ratifying the Kyoto Protocol on Climate Change at a special ceremony at the United Nations headquarters in New York.

The recent UN World Summit on Sustainable Development held in South Africa called on countries to “ diversify energy supply by developing advanced, cleaner, more efficient, affordable and cost-effective energy technologies” with a request that countries must “ with a sense of urgency, substantially increase the global share of renewable energy resources.”

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T H E P O T E N T I A L F O R R E N E W A B L E E N E R G Y U S A G E I N A Q U A C U L T U R E

One of the fundamental issues facing all of us today is proper management of our energy resources. The current generation has a responsibility to ensure that energy is used efficiently and with minimum impact on the environment. As considerations of fuel diversity, market uncertainties and environmental concerns are increasingly factored into electric utility resource planning, renewable energy technologies are beginning to find their place in the utility resource portfolio.

Much has been written about the use of renewable energy and there is a myriad of useful publications and manuals. The purpose of this report, however, is to outline the various methods of using renewable energy with particular reference to aquaculture. Whilst energy costs in aquaculture generally come behind salary, feed and stock costs, it is nevertheless a significant part of operating cost. The reduction of operating costs is the key to increasing competitiveness and long-term profitability. As will be outlined in the first two chapters, energy conservation is an important step in reducing costs. Perhaps surprisingly, some of the biggest proponents of energy conservation are the electricity suppliers themselves who are under increasing pressure to meet supply demands and indeed at times have to restrict supply.

Aquaculture is a growing industry and one that has its fair share of criticism. The location of aquaculture operations in remote areas may lend it to renewable energy usage far easier than other small and medium sized enterprises. While cost benefits are still marginal, the overall public perception of renewable energy being environmentally friendly may be an important factor in improving the image of aquaculture.

CASE STUDY The report highlights a number of different sources of renewable energy and discusses their potential application in aquaculture. In order to assess the potential impact of each of the methods, practical examples are worked out in 3 fictional case studies and these are examined where relevant.

C A S E S T U D Y 1 : P A C I F I C O Y S T E R F A R M

The farm is situated in the northwestern part of Ireland and produces 50 tonnes/annum of Crassostrea gigas oysters. There is an onshore shed, which houses a power washer, grading machine and small purification unit. Two holding ponds allow the farm to keep produce for the market and hold graded stock during slack tides. There is also general electrical equipment including the all-important kettle! Energy usage is consistent throughout the year.

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Case study 1 is a 5o tonnes/year Pacific Oyster farm. The farm is situated on an exposed site.

C A S E S T U D Y 2 : F R E S H W A T E R T R O U T F A R M

The farm is situated in an inland rural area in Northern Ireland and produces 60 tonnes/annum of Rainbow Trout. The farm is situated on the site of an old mill and draws water by gravity from an adjacent river. There is an onsite workshop and hatchery unit containing graders, fish pumps, and an aeration system. Energy usage varies throughout the year with high consumption during dry spells and when the hatchery unit is operating during the winter.

Case study 2 is a 6o-tonnes/year Rainbow Trout farm situated in Northern Ireland. The farm is situated adjacent to a river from which its water source is drawn.

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C A S E S T U D Y 3 : M A R I N E F I N F I S H R E C I R C F A C I L I T Y

The farm is situated in southern Ireland and produces 200 tonnes/annum of Turbot/Halibut. The farm is situated on the coast and replaces 5% of its water per day. The facility is only two years old and so the equipment is relatively new. The building was designed to conserve as much energy as possible and is well insulated to prevent heat loss. The facility has a high-energy demand throughout the year.

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Case study 3 is a 200-tonnes/annum marine finfish farm situated in southwestern Ireland.


ENERGY EFFIENCY "Electricity seems destined to play an important part in the arts and industries." Ambrose Bierce 1876

A ny thewhela

analysis of the prospects for using renewable energy must first assess current energy load and, in particular, shortcomings in the system, ich lead to energy wastage. There is little point in developing an borate integrated energy system without first addressing energy leaks

and loss. A common sight on most farms is the DIY approach to electrical maintenance. Wires fused together and wrapped in insulating tape, thermostats left to seize up and water pumps operating at inefficient levels all combine to reduce the efficient use of the energy being drawn upon. Northern Ireland Electricity estimates that these losses can add 10% to an average farms electricity bill.

Many homeowners have in recent times become aware of the need for energy conservation. Items such as insulated water cylinders and attics are now accepted standards in all new homes. The application of this ethos in the commercial environment has been slow but is now being instigated, directed by national policy, and business is accepting the important role it has to play in implementing energy reduction programs.

Energy efficiency can be broadly addressed in the following areas:

Efficient Technology Many aquaculture operations still use equipment and machinery that they established their business with. While this loyalty is admirable it is increasingly misplaced. Advances in technological design and energy efficiency mean that change is not only necessary for depreciation purposes but also to make your operation more cost effective. High volume pumps for example now have loadings as low as 0.75kW in comparison to the 2.2kW pumps in standard use in the recent past. Modern control switches and thermostatically controlled apparatus’ mean that equipment is in use for the minimum time necessary. The benefits of choosing these technologies generally more than compensate for any additional cost. The availability of European and government funding to the sector specifically aimed at

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the purchase of new capital items means that there has seldom been a better time to update your farm’s equipment.

Efficient Design & Planning The importance of efficient design and planning cannot be over-stressed. Whilst many aquaculture operations have to adapt their current systems to become more energy efficient, a new entrant or the expansion of an existing site gives the designer a blank canvas. A much-overlooked advantage is the ability to allow for reduction of equipment sizes in the future and this should be taken into consideration when planning the layout of a farm. It is always of benefit to ask your local electricity company to look at the plans and suggest any changes or areas, which can be made more energy efficient.

Efficient Purchasing & Maintenance of Equipment It is always tempting to select the cheapest equipment because of budgetary restrictions but this rarely works out in the long run. In general, consideration should be taken of the equipment's running cost over 5 years.1 Regular maintenance and servicing of equipment ensures longevity and efficiency. This is particularly important in the aquaculture sector where the environment is harsh on equipment and machinery, as well as fittings and fixtures.

The European Union introduced mandatory efficiency labelling of all domestic appliances in 1992. The label ranks appliance efficiency from A to G, A being the most efficient and G being the least efficient. The mandatory nature of the program has spurred manufacturers to improve the efficiency of their products. In Germany for example the efficiency of products on the market improved by 16.1% from 1993-1996. The labelling is only mandatory on domestic appliances but may be extended to small-scale industrial appliances in the near future.

1 The standard depreciation for industrial equipment is 20%/annum, however the harsh working environment of aquaculture means that 25% is more appropriate. Electric motors typically have 3 months running costs = capital cost.

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So what in practice does all this mean for people in the aquaculture industry? The following bullet points outline steps that can be taken to improve energy efficiency on most farms and will probably lead to a reduction in energy costs.

Ensure pumps, lights and motors are switched off when not needed;

Repair damaged appliances, insulation etc.;

Check timer units are set correctly;

Ensure the farm is on the right tariff program with your electrical supplier;

Manage farm load to take advantage of special tariffs;

Use energy efficient equipment.

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Energy Loads "Electricity, the peril the wind sings to, in the wires on a grey day." Janet Frame E L E C T R I C I T Y

G L O S S A R Y

AC - "Alternating current".

Mains electricity & also

generators.

Amps - measure of electric

current

Current - The flow of electricity

measured in amps

DC -"Direct Current" as used in

charging batteries.

Gigawatt (GW) – 1,000 MWs

Inverter - Device for

converting d.c into a.c

Load - Anything which uses

electricity

Mains - grid electricity supplied

at 230 volt a.c

Megawatt (MW) – 1,000 kWs

Power - Rate of delivery of

energy. Energy per hour.

Measured in watts (W) or

Kilowatts (kW). 1kW=1,000W.

Rectifier - Device which

converts a.c to d.c

TWh - 1,000,000,000 kWh

Voltage - Electrical 'pressure

drop' between two wires.

F irstly it is important to understand what a load is and the exact meaning of energy and power. Energy in this context refers to what you pay for, from your electricity supplier. Energy is measured in units and these units appear on your electricity meter. A unit of electricity is referred to as a 'Kilowatt-

hour' (kWh). All electrical appliances are obliged by law to display their rating or the number of watts, which the appliance will use in one hour if running continuously. For example if a toaster has a rating of 500 watts it will use ½ of a unit in one hour. Similarly an electric water pump with a rating of 2.2 kW will use 2.2 units per hour if running continuously. The average home in the UK and Ireland uses around 5,000kWh/annum. The bulk of this electricity is used up in heating homes and powering electrical appliances such as cookers, fridges, televisions and so on. An aquaculture facility may use some of the above appliances, but pumps, machinery etc. consume the majority of electricity. Looking at each case study individually we can calculate the load and subsequently assess the potential for using different sources of renewable energy.

The system load is the likely number of kWh used over a period of time. By assessing what the load is likely to be we can calculate how much energy is needed and consequently the size of power source required in order to power all our appliances. Working out the system load is always approximate. For instance, whilst a fridge may use 1kW, it is constantly switching itself on and off by thermostatic control and therefore isn't using as much energy as initially assumed. Looking back over old electricity bills will give us an idea of the average usage over a month but doesn't indicate the peak load.

In the tables below we have tried to show an estimate of the loads in relation to each case study and energy usage/week. With this information we will then look at

the various types of renewable energy and assess their appropriateness to aquaculture.

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Equipment Rated Load Hours used

per week Total Load per

week

Purification System

400W 84 33.6 kWh

Holding Pond Aerator

2.2kW 7 15.4 kWh

Grader System

600W 15 9 kWh

Water Pumps 2kW 2 4 kWh

Power Washer 200W 2 0.4 kWh

Lighting 300W 15 4.5 kWh

General Domestic

Kettle

Fridge

Microwave

2.4kW

100W

800W

-

-

-

1.2 kWh

5 kWh

0.2 kWh

Office Computer Heater, etc.

300W 20 6 kWh

Total 9.3kW 79.3kWh

Fig 1.1 Energy Load of Pacific Oyster farm

The maximum load is 9.3kW and the weekly load is 79.3kWh. This loading is low and consumption is on par with an average family home. The purification system uses the most power followed by the holding pond aerator. Interestingly the kettle has the highest load of all the appliances.

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C A S E S T U D Y 2 : R A I N B O W T R O U T F A R M



week

Aeration System

14kW 17 238 kWh

Fish Pump 2.2kW 7 15.4 kWh

Grader System

400W 4 1.6 kWh

Water Pumps 2kW 2 4 kWh

Hatchery

400W 10 4 kWh

Power Washer 400W 2 0.8 kWh

Lighting 300W 15 4.5 kWh

General Domestic

Kettle

Fridge

Microwave

2.4kW

100W

800W

-

-

-

1.2 kWh

5 kWh

0.2 kWh


300W 20 6 kWh

Total 23.3kW 280.7kWh

Fig 1.2 Energy Load of Rainbow Trout Farm

The aeration system uses the highest amount of power. The system is used generally during the summer months, but in this case we have spread the energy load over the full year.

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C A S E S T U D Y 3 : M A R I N E R E C I R C F A R M



week

Recirc System 80 kWh 168 13,440 kWh

Grader System

600W 15 9 kWh

Ancillary Equipment

6kW 50 300 kWh

General Domestic

Kettle

Fridge

Microwave

2.4kW

100W

800W

-

-

-

1.2 kWh

5 kWh

0.2 kWh


600W 20 12 kWh

Total 90.5kW 13,767 kWh

Fig 1.3 Energy Load of Marine Recirc Farm

The marine recirc facility has by the far the biggest energy consumption of the three case studies. Energy costs run into thousands of pounds per annum. To separate out all the power ratings for the system would require a long list so the ratings are grouped. Energy usage is constant throughout the year to ensure a stable growing environment for the fish.

Having an estimate of the power consumption of the three case studies we can now look at the different renewable energy systems with an appreciation of just how much power is required.

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Economical water heating system for fish farm

The Centre for the Analysis and Dissemination of Demonstrated Energy Technologies ran a research project in conjunction with Alleghanys Inc. fish farm, testing a new heating system on its Trout production unit in Quebec, Canada. Project Aim To raise the water temperature of the farm allowing enhanced salmonid growth. Increase production, lower heating costs by recovering heat from effluent. Demonstrate the reliability and the economic advantages of a heat pump system in this application. Allow thermal control in respect with energy saving goals. The Principle The system heats water from a natural source (groundwater) and carries it to two breeding pools. Two steps are used in the heat recovery process. Firstly a passive heat exchanger with the outgoing used water from the breeding pools heats the incoming groundwater (pumped from four supply wells each 30m deep with a flow rate of 94.5 l/s). The second step is an active heat exchange through a heat pump. This device is connected to the exhaust side of the used water heat exchanger from the first step. By this means heat is progressively taken from the used water that is carried out of the system, and injected into the fresh water. The heat pump operates with HCFC-22, a non CFC refrigerant. The Result The overall system reduced energy consumption to 184.6MWh saving approximately 87% over a conventional system. Moreover an increase in production of 40% has been estimated as a result of the increased and constant temperature. There is also a reduction of CO2 emissions of 218 ton/year. The initial investment for the system was $85,000, which includes the passive heat exchanger, filter, pumps, heat pump and piping. The specific energy cost is $26.4/(m3/h)/0C/year. Source: CADDET

Result

Energy Consumption reduced by 87%

Savings of $23,657 and $14,035 compared respectively to electrical and fuel oil systems

Payback period less than 1,5 years

Use of non-CFC refrigerants

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T H E P O T E N T I A L F O R R E N E W A B L E E N E R G Y U S A G E I N A Q U A C U L T U R E 4 WIND POWER "Take care, your worship, those things over there are not giants but windmills." CERVANTES

P ower from the wind is probably the most familiar of all renewable energy sources. The Middle Ages saw wind being harnessed to pump water and mill grain and this continues in many parts of the world where the mainstream electricity grid is unavailable or prohibitively costly. While most

wind power applications in Europe concentrate on electricity generation, the potential for wind pumps is also applicable to aquaculture and so will be reviewed here as well. The technology being developed to harness wind power has accelerated at a great pace over the last 10 years bringing costs down and efficiency up.

WIND TURBINES By far the most common method of harnessing the wind in Europe is by using horizontal axis wind turbines. Wind turns a rotor or blade, which converts the energy to electricity through a gearbox and generator situated in the windmill tower. This form of electricity generation has been used since the 19th century but only began to receive serious attention in the 1970s when the oil crisis amongst other things resolved the global communities minds to developing renewable sources of energy. In the past 20 years, therefore, there has been a dramatic decrease in the cost of wind machines and significant improvements in system performance, making wind power the most commercially viable of all renewable sources in grid connected electricity-generating applications.

The basic structure of a horizontal axis windmill can be seen in the diagram opposite.

Wind Turbine components (Courtesy of Irish Energy Centre)

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European & Irish Production overview

In 1995, electricity production in the EU amounted to 2384TWh. The estimated annual wind potential is 588 TWh (land based resource), which is adequate for a 20% penetration of supply. This excludes the annual offshore resource estimated to be in excess of 2500 TWh.2

Current government policy is to increase the use of renewable energy sources to generate electricity through the Alternative Energy Requirement (AER)3 - a series of competitions in which prospective generators tender for contracts to sell electricity to electricity companies. It is envisaged that much of the new capacity will derive from wind farm developments, which so far have been the major beneficiary from AER schemes and are expected to be so in the future. Ireland didn't have its first wind farm until 1992 when a 6.45 MW farm with 21 turbines was opened in Co. Mayo supplying approximately 3,000 homes. Ireland intends to increase annual production to 470MW by 2010 from its present production of 90MW. Some of this increase will be through offshore farms, which will be discussed later in this section.

Large Wind Turbines have become an increasingly common site on the Irish Landscape

2 Source: European Commission - Directorate- General for Energy. Wind Energy - The Facts

3 AER – The Dept of Public Enterprise invite tenders for CHP (Combined Heat and Power) generation through renewable energy. Grant assistance is available and successful tenders sell power to the ESB.

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Country Electricity Production 2000

(TWh/annum)

Technical wind potential Wijk and Coelingh4

(TWh/annum)

Realistic potential = lesser of 20% consumption and technical potential

(TWh/annum)

Ireland

UK

Austria

Belgium

Denmark

Finland

France

Germany

Greece

Italy

Luxembourg

The Netherlands

Portugal

Spain

Sweden

Total EU

17

379

60

82

31

66

491

534

41

207

1

89

32

178

176

2384

44

114

3

5

27

7

85

24

44

69

0

7

15

86

58

588

3.4

75.8

3

5

6.2

7

85

24

8.2

41.4

0

7

6.4

35.6

35.2

343.2

FIG 2.1 The European wind energy potential and electricity consumption. EC Directorate-General for Energy.

OFFSHORE WIND ENERGY Offshore wind has the potential to deliver substantial quantities of energy - at a price which is cheaper than most of the other renewable energies, but dearer than onshore. Offshore wind energy has the added attraction that it has minimal environmental effects and, broadly speaking, the best European resources are reasonably well located relative to the centres of electricity demand. Wind speeds are generally higher offshore than on land, although the upland regions of Ireland, Scotland, Italy and Greece, do yield higher speeds.

4 Van Wijk AJM and Coelingh JP " Wind Potential in the OECD countries" 1993

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Recently in Ireland applications have been made for numerous offshore wind farms, particularly on the East Coast. These farms have the potential to supply up to 10% extra electricity to the grid alone substantially increasing Irelands use of renewable resources. New foundation technologies, using steel rather than concrete have improved the economics of offshore wind technology dramatically. Wind turbines at sea would have a longer design lifetime due to lower mechanical fatigue loads.

There is no doubt that European wind technology has advanced at a dramatic pace. In a matter of a decade and a half it has evolved from an industry making small, simple and sometimes unreliable machines into a technology, which can compete with the well-established conventional forms of power generation. Irelands potential is great given the abundance of exposed sites, which lend themselves to high and constant wind speeds. Wind turbines in ‘farms’ of 4 to 50 machines, which supply the national grid, are beyond the scope of this report given the large scale necessary to supply cost effectively and the prohibitive cost to a small sector such as aquaculture. It is however important to have highlighted the policy of the EU to wind energy and the Irish governments commitment to the AER in further explaining the potential that smaller wind turbines can play in energy production for aquaculture.

An offshore wind farm in Denmark

Wind Power System Components

Wind Turbine

Tower

Cable to Battery

Battery

Fusebox

Shunt Regulator

Inverter

Safety Earthing

System Controller

Standby Generator

Battery Charger

Small Scale Wind Turbine Systems

There are many different types of small scale wind systems in use in the UK and Ireland, and to explain the different benefits of them all would take numerous chapters, so we will just concentrate on the basic components of the system, which are very similar. The main problem in harnessing the wind is that it carries very little energy when blowing lightly and an abundance when it blows strong as in a gale. Most parts of Ireland have various degrees of wind strength, having calm days with little or no breeze and days when it's dangerous to stick your head out the door. It's precisely because of this inconsistency in wind power that small units have battery systems. The batteries store energy when the wind is blowing and provide a back up for a period during times of little or no breeze.

Basic principle of windpower

As already mentioned wind turbines consist of a rotor or set of blades, which turns when faced into the wind. This is achieved by a hinged tail vane or rotor design, which steers the blades to get the maximum force from the wind. This also has the effect of steering the blades out of the wind in a gale where the strength of the

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wind may cause damage to the turbine. As the blades turn they rotate a generator through a gearbox. The generator, which is situated in the nacelle or outer casing, generates AC power, which travels down a cable to the battery. The AC power must then be converted to DC, which is what the battery stores. This is done quite simply through a semiconductor system called a rectifier. A device called a shunt regulator stops a battery from overcharging when there is a surfeit of wind.

The power that is stored in the battery is as we have said in DC form. Some equipment can be run off DC, but all mains equipment runs off AC, so we need to convert the power back to AC to run items such as pumps, graders etc. To do this we need a device called an inverter. Inverters are widely used on windpowered systems to run mains powered equipment from batteries. An inverter can be an expensive piece of the system but plays a crucial role in converting wind energy into usable power.

How much power a wind turbine can provide depends on a number of factors, but generally rotor diameter and windspeed. Rotor diameters vary from model to model. Measured in metres, the diameter is the size of the circle swept by the blades measured from one side to the other. Diameters vary from 0.5m to 50m and consequently so does the power output from just 20W to current plans for a 3MW wind turbine, which would provide enough power for a staggering 1,500 homes alone. This report is concentrating on the use of smaller turbines (<4.5Kw), which have a rotor diameter of between 0.5m to 6.1m. The number of blades can also affect the efficiency of the turbine. This also varies with up to six blades being used. In practice most wind turbines use 2-3 blades.

A 3 bladed 1.5 MW windmill in Denmark

Windspeed

Windspeed obviously has a great effect on the amount of energy that can be produced. In general Ireland has abundant wind, but this varies significantly from place to place, depending on weather systems and local topography. It is important to note that wind energy increases with height above sea level. Trees, buildings and

other structures slow down and deflect the wind. As with most aquaculture operations site is everything and this is no different with windpower. The most important criteria when determining whether a site is suitable is the average windspeed measured in metres per second (m/s). Windspeed figures can be got from the meteorological service but these figures will most likely not be site specific. A site appraisal looking at the surrounding area and siting an anemometer (windspeed measuring instrument) for a period of time will give you an indication of the average windspeed.

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Tower height and position is of critical importance and even more so in sheltered areas where extra height may give access to up to 30% more windspeed. Sites for small wind turbines are nearly always near some small buildings or trees and so the simplest advice is to try and place the windmill in the most exposed area possible and to have the tower as high as possible.

FIG 2.2 Frequency of wind directions for groups of wind speeds at selected stations. Met Eireann.

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The majority of small wind turbines will work at their most efficient at windspeed of 6-12m/s. Nearly all wind turbines will however provide some power in winds as light as 3m/s. These figures emphasise the importance of battery storage and/or back up supply whether from the mains, diesel generator or another source of renewable energy.

Energy Outputs of Wind Turbines

Turbine Rotor Diameter Average Windspeed

1m 2m 3m 5m

3m/s 0.5 2.5 6 16

4m/s 1.5 6 15 40

5m/s 3 12 25 75

6m/s 4 17 40 110

Fig 2.3 Energy Output of Wind Turbines in kWh

Using the loads calculated in chapter 3, lets look at our case studies and the use of various wind systems.


We know from chapter 3, that the load associated with the pacific oyster farm is 9.3kW with an average weekly consumption of 79.3 kWh. The load, however,

varies at various times in the year and during the week. The farm is in a windy place, being beside the sea, with prevailing winds from the southwest. We can estimate an average windspeed of 6m/s at a height of 20m. From the output table we can estimate that a 5m-diameter wind turbine should give adequate cover. The cost of this type of machine including batteries is shown. Whilst this may seem prohibitively costly, grant aid is available. Nevertheless, a long payback

time is involved (>10 years) and wind power is not viable in this case unless grid

Item Cost € (estimate)

Wind Turbine 6,500

Tower 3,600

Battery & Cable 4,000

Inverter 3,800

Shunt Regulator 1,300

19,200

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electricity is not available. A smaller system just powering a number of appliances may make more financial sense.


We know from chapter 3, that the load associated with the Rainbow Trout farm is 23.3kW with an average weekly consumption of 280.7 kWh. The load varies at various times in the year and during the week. The farm is situated inland and the average windspeed is 4m/s. Given the relatively low wind speed it would take a wind turbine of 8m diameter and larger to power the site. Using a wind turbine in this situation is uneconomical. A smaller system could be used to power just part of the energy needs.


The farm has high energy usage running at around 13.67MWh per week. Installing a small scale system is again uneconomical. The development of offshore wind generating systems has dramatically improved the cost of wind energy. It is possible to have a 20% increase in windspeed with an offshore turbine, This would result in a 75% increase in electricity generation. 600kW – 1.5MW machines generate elctricity at a cost of around 4-6 cent per kWh. If the marine recirc facility used an offshore wind turbine it could in theory pay for itsself in 8-10 years. The machines have a lifespan of 25 years giving plenty of energy savings over a twenty year period.

As a guideline land based wind turbine systems cost around €1,700 - €5,000 per kW installed depending on size. They are obviously more economical on a larger scale when it is also viable to sell excess wind energy into the grid. One of the big drawbacks on this side of the Atlantic is that if using renewable energy you are not allowed to run your meter backwards by your power supplier. This is known as ‘net metering’ and is currently being lobbied for by the Irish Wind Energy Association among others. If it was possible, most businesses could have small-scale units, running back units used off the mains and reducing their bills.

Windpowered turbines may have a part to play in aquaculture and this is solely site dependent. Any of the windpower companies will do a thorough site assessment and calculate just how much power can be generated and at what cost. It is certainly worth exploring the possibility if you feel your site has wind speeds of 6m/s or higher.

Note: Power from wind is extremely sensitive to wind speed, being a function of the wind speed3, therefore conclusions here are dependant on the assumptions regarding wind speeds at the three case study sites.

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WINDPUMPS Windpumps (water pumping windmill) aren't the most common site in the Irish landscape and most people when asked first would find it hard to recall ever seeing one. Yet think of an old western movie or conjure up images of the outback or Mongolia and windpumps go hand in hand with the landscape. These rusty old pumps with their large multi-bladed heads have been pumping water from wells

worldwide for generations. Reliable and hardy they bring water to the surface in areas where the nearest grid electricity may be thousands of miles away. Why these were never common in Ireland could be due to the abundance of rainwater and springs, but they may yet have a part to play in aquaculture.

As with wind turbines, wind moves the blades, which are faced to the wind by a hinged tail vane. There are more blades on a windpump than a conventional wind turbine, around 18-20. As the

blades turn they usually drive a piston pump, which draws the water from the well, borehole or river (other pumps may be also be used). Windpumps are very low maintenance and may just require a bearing greasing once a year. They can operate in winds as low as 2m/s and swing out of action in winds over 15m/s. Most windpumps are built on conventional lattice towers but some German and Dutch designs are similar to the tubular steel towers of modern wind turbines.

The windpump shown below is of conventional construction and stands around 9m tall with a 5.0m rotor diameter. Typical output for these types of waterpumps is 93m3/day to 301m3/day at a 5m head. They can, however, pump water from up to 140m depth. This type of water pumping may have an application in numerous

types of aquaculture from marine hatchery and recirc facilities to low volume freshwater operations such as perch farming.

Windpumps need to be situated over the water source. For aquaculture purposes this may mean digging a feeder channel to bring source water directly underneath the pump. The wind pump is able to pump water up to 1km and a height of around 50m. As with wind turbines, the higher the tower, the greater the performance. However, planning restrictions may restrict the user to a standard 9m tower.

The Broads authority in the UK has trialled a Dutch design wind pump

19


for low head application. This pump is only 4.5m tall and can pump up to 60m3 /hr. This type of pump could be suitable where planning restricts traditional lattice type installations.

In America and Canada windpumps are also used to aerate dugouts (watering holes). Up until the 1980s farms used electrically powered air compressors. However more recently, bank mounted windpumps have proven to be a reliable low cost alternative. Similar systems could be used in aquaculture installations to provide aeration to pond water. A system trialled in Alberta, Canada used a 3-blade high-speed propeller driving a 6-inch diaphragm pump. A system of 2 check valves and a 3/8-inch diameter air hose delivered air below the water surface. The pump delivered on average 3.3 cubic feet per minute. This is around 3 times the airflow needed to maintain dissolved oxygen necessary in a one acre perch pond and so has great potential in eliminating the need for expensive 2.2kW paddle aerators which use up more of your farms power. The windpump in this case started rotating at a windspeed of just 3 miles/ hr and reached 400 revolutions per minute at wind speeds of 16 miles / hr.

Let us now look at the application of windpump technology for our three case studies.


The oyster farm purifies its product in a simple batch purification system. The system holds 1,200 l of water and this is replaced every 42 hrs. A mains powered pump pumps this water into the tanks through a header tank, which is filled at high tide. The farm also has two storage and holding ponds in which stock is placed after grading when ready for sale. These holding ponds have a capacity of 60m3 each and are filled by a mains powered pump at high water. The water is replaced once a week.

The farm pumps relatively little water and so any application of windpump technology is unlikely to be cost efficient in the short to medium term. A shellfish hatchery or nursery may find it viable to use windpumps and aerators, as the quantities of water used are far higher. As is the case with wind turbines the coastal nature of this case study makes it very well positioned to exploit wind energy.

20

No. Of Pumps 2

Pump load 4kW

Volume pumped/week 124.8m3

Cost/week €0.55



The trout farm is situated on a river and takes approx. 36 million litres/day by gravity flow. Pumping such a huge volume of water would be financially prohibitive. An aeration system on the farm operates during the summer when dissolved oxygen is low. From the table we can see that a not inconsiderable amount is spent providing energy for the aeration system during the summer. The

installation of a windpump system would provide the same amount of aeration but at a fraction of the cost. The existing aeration system could be used during times of low wind speed5.

No. of aerators 7

Pump load 14kW

Aeration amount

1,638Kg O2 added

Energy Cost/week €30

Using a windpump may be viable on a site not fed by gravity flow and where the water could be reused and recycled in order to reduce the daily intake.


The marine recirc farm replaces 5% of its water volume per day amounting to 864 m3/day. The pumping costs in order to achieve this replacement are in the order of €20/week. A windpump unit could replace this volume over a payback period of 20 years and even at that the supply would be variable. A smaller windpump could be used to pump non-time restrictive water such as in a settlement tank. The cost viability for this particular type of unit is still prohibitive.

One area of aquaculture where windpumps could be used is perch farming. Although relatively new, perch farming requires low water exchange and windpumps could be used in fields, which are a distance from the nearest electricity point. The viability of such a system has yet to be proven.

5 Aeration calculations based on 'Technical Talk', Pisces Aquacultural engineers

21


HYDRO POWER "Let not one river or stream or rivulet reach the sea without yielding its energy potential." John Seymour

H ydro power (water power) is one of the most reliable methods of using renewable energy. It is used by power companies world wide because of its availability, consistency and cost effectiveness. Hydro schemes whilst expensive to build often go hand in hand with water reservoir projects so

the benefits are two fold. Unfortunately for power companies it is only viable to dam the bigger rivers for hydro use. For the average householder, however, that stream at the bottom of the garden may be able to power the electricity needs and it may even be possible to sell some electricity back to the power company. Power companies may purchase energy made from renewable sources and many old mills have turbines working away happily, making money for their owners.

D I D Y O U

K N O W ?

Over 99% of Norway's

electricity is produced by

Hydro power.

Hydropower of course first came to prominence long before electricity was discovered. At one time hydropower was employed on many sites in Europe and North America. It was primarily used to grind grain where water had a vertical drop of more than a few feet and sufficient flow. Less common, but of no less importance, was the use of hydro to provide shaft power for textile plants, sawmills and other manufacturing operations. Hydropower provides 20% of the worlds electricity and is by far the biggest contributor of renewable energy contributing over 97% of all renewable energy. With the advances in modern turbines, hydropower is up to 90% efficient at converting energy compared with 50% efficiency at the most for fossil fuel use.

Ballyshannon Hydrostation, Co. Donegal with the salmon hatchery in foreground

22


Top Hydroelectric Producing Countries

0

50

100

150

200

250

300

350

Canada USA Russia Brazil China Norway Japan Sweden India France

Bill

ion

kW

h

Fig 3.1 Top Hydroelectric Producing Countries

Basic Principles of Hydropower

Whilst hydropower can be used for mechanical means such as milling grains we will concentrate on the use of hydropower for electrical generation. Hydropower plants capture the energy of falling water to generate electricity. A turbine converts the kinetic energy of the falling water into mechanical energy. Then a generator converts this mechanical energy into electrical energy. Hydro plants range in size from 'micro-hydro' that power a home or business to giant dams like the Hoover Dam in America, which provides electricity for millions of people.

Most hydro schemes include the following components: n

Dam- Raises the water level of the river to create fallthe flow of water. The reservoir that is formed behinstored energy.

Turbine- The force of falling water pushing against ththe turbine to spin. A water turbine is much like a winis provided by falling water instead of wind. The turbenergy of falling water into mechanical energy.

23

Parteen Hydro statio

ing water. Also controls d the dam is, in effect,

e turbines blades causes dmill, except the energy ine converts the kinetic


Generator- Connected to the turbine by shafts and possibly gears, so when the turbine spins it causes the generator to spin as well. This converts the mechanical energy from the turbine into electric energy. Generators in hydropower plants work just like the generators in other types of power plants.

The use of hydro plants on rivers is not without its detractors. There is no doubt that large scale hydro schemes impact on the landscape, environment and fisheries, not least by flooding thousand of acres of land. Promoters of such schemes believe the benefits far outweigh the negative impacts and power companies have spent millons regenerating wetlands and improving fisheries. For instance the ESB have developed their

own fish farms for restocking areas affected by their schemes.

Generators inside a Hydropower station

How much electricity a hydropower plant produces depends on two factors

How far the water falls vertically- The further the water falls the more power it has and subsequently the more energy. The height of the dam usually dictates this. This vertical height is known as the head of water and is quoted in metres.

The amount of water falling- Quite simply the volumetric flow rate of the river, although dams can back up the water supply thereby increasing the water flow for short periods.

Micro-Hydro systems

Micro-Hydro systems could be of particular benefit to aquaculture and especially freshwater-based farms. Many trout and salmon farms are based on rivers with great volumes of water passing through each day. This energy could be harnessed

to provide valuable energy to the farm. Micro-Hydro systems can be of various designs depending on site and flow, and it is possible to have a series of turbines on the one river system or farm.

Siting a hydro system is much more site-specific than a wind or photovoltaic (PV-solar) system. A sufficient quantity of falling water must be available. More head is usually better because the system uses less water

and the equipment can be smaller. The turbine also runs at a higher speed. Since power is the product of head and flow, more flow is required at a lower head to generate the same power level.

A Micro-Hydro turbine on a small stream

24


The power or kW that can be obtained from a Micro-Hydro system can be calculated using a simple equation.

Power (kW) = (Head * River Flow * Efficiency) *9.92

Where

Head = Distance water falls to turbine in metres (m)

River flow = amount of water flowing in river or raceway measured in m3/s

Efficiency = This depends on how well the hydro plant converts kinetic energy to mechanical energy to electricity. Can vary from 59% (0.5) to 90% (0.90).

9.92 is a factor to convert units of metres and seconds to kilowatts

Let us assume that we want to place a micro hydro system on the inlet channel to our trout farm. The head is 1.5m and the flow is 4m3/s. We will assume an efficiency rating of 80%.

(1.5 * 0.4 * 0.8) * 9.92 = 4.76kW

4.76 kW could be enough energy to supply for aerators or a feeder system and would save this farm over €3,000 /annum. The system would probably pay for itself within 3 years.

Hydro systems can be used for direct power or to charge batteries similar to systems used in conjunction with wind turbines.


The oyster farm as we have already seen does not pump large amounts of water and doesn’t have access to flowing water on site. Hydropower is therefore not applicable.


The rainbow trout farm is ideally placed to harness energy from hydropower. Large volumes of water are continuously flowing through the site with an overall head between inlet and outlet of 3 metres. Rather than place one large turbine on the raceway it may be more beneficial to install a series of micro turbines on the farm, which could power much of the site’s energy needs. If a large turbine was placed on the site it could supply electricity for sale to the local Power Company. Electricity companies are obliged to try and purchase electricity made from renewable energy. There would be little disadvantage in installing turbines on site.

25


The entrance grid has to be cleared of leaves anyway during the winter months and this would adequately protect the turbine. The water being used is still available to the farm and the water quality will remain the same. The initial capital cost may be high but systems could pay for themselves in 3-4 years time. Many old millraces, which have not been utilised by fish farms, are used for electricity generation already, and with slight modification existing civil works may be used for energy production, thus reducing capital costs substantially.


The use of hydropower in this system is uncertain. There is no natural head on the site as all water is pumped except for water returning to the sea. It may be possible to place a small turbine unit somewhere in the system to recoup energy used by the pumps but this might need extensive redesign and is likely to be more troublesome and not cost effective. If large volumes are returned to the sea, a small turbine could be placed at the outflow, which could contribute to the energy needed for the inflow pump.

26


Ocean Energy The ocean and seas can produce two types of energy: thermal energy from the sun’s heat, and mechanical energy from the tides and waves.

The oceans cover more than 70% of the earth’s surface, making them the world’s largest solar collectors. The sun’s heat warms the surface water a lot more than the deep ocean water, and this temperature difference creates thermal energy. Ocean thermal energy is used for many applications, including electricity generation. There are three types of electricity conversion systems: closed-cycle, open cycle, and hybrid. Closed cycle systems use the ocean’s warm surface water to vaporise a working fluid, which has a low-boiling point, such as ammonia. The vapour expands and turns a turbine. Open-cycle systems actually boil the seawater by operating at low pressures. This produces steam that passes through a turbine. Hybrid systems combine both methods.

Ocean mechanical energy is quite different from thermal energy. Even though the sun affects all ocean activity, tides are driven primarily by the gravitational pull of the moon, and waves are driven primarily by the winds. As a result, tides and waves are intermittent (though predictable) sources of energy, while thermal energy is fairly constant.

A barrage (dam) is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a generator. For wave energy conversion there are three basic systems: channel systems that funnel the waves into reservoirs; float systems that drive hydraulic pumps; and oscillating water column systems that use the waves to compress air within a container. The mechanical power created from these systems either directly activates a generator or transfers to a working liquid, water, or air, which then drives a turbine/generator. Tidal power plants generally need a large tidal range and are costly.

The only major tidal power scheme operating anywhere in the world is in the Rance estuary between Dinard and Saint Malo in France, where a barrage with 240 MW of turbines was completed in 1966, as a pilot scheme for a prospective larger barrage across the Mont Saint Michel bay. The scheme has operated regularly and reliably for 25 years. The larger scheme was never completed as the French concentrated their resources on nubeen suggested for the Severn estuary in thMWhs per annum, and in the Bay 1400MWhs/annum. The scale of the envirprojects can be shown at the shelved Canadiastored from an incoming tide, the tidal measurable in New York harbour, some 800k

27

La Rance Tidal Station in Brittany, France

clear power. Large schemes have e UK, which could yield 8640 of Fundy, Canada, yielding

onmental implications of these n project. If the waters had been changes would still have been m south!


The environmental implications as well as the huge capital cost of such large schemes have prohibited the development of this resource. However, less mature technologies have been moved from laboratory tests to field trials in the open sea recently, with Engineering Business installing a prototype of its Stingray tidal stream generator off the Shetland Islands in September 2001. At the same time, Marine Current Turbines (MCT) and Tidal

Hydraulic Generators are installing devices off Pembrokeshire and Devon.

La Rance schematic, courtesy of MARE 25

Development of wave energy is also at a crucial state. German and British scientists are currently developing an underwater power generator, which uses the currents as well as tides and the Gulf Stream to produce electricity. They employ the same principles as behind a wind turbine: the oncoming water turns the blades of a rotor. Because the density of water is so much higher than the air’s, even very low tidal flow can produce electricity.

The pilot project ‘Seaflow’ will be installed next year in the Bristol channel off the coast of Cornwall. The tidal current here measures around 8km/h. Rotors of 15m width will produce 350kW. The project is made viable by its low installation costs. The technical specifications derive from wind power, they only need to be ‘water proofed’. Another advantage of these underwater generators is that they are not influenced by storms. Under water the tidal currents never change. From an environmental point of view the siting of these underwater rotors should not have a high impact on biodiversity either – areas with high currents generally do not provide comfortable spawning grounds or a habitat for an extensive number of species. Another advantage is the low visual impact, which usually restricts the development of land based wind farms. Having analysed 106 possible sites in Europe, scientists concluded that generators at sites such as Pentland Firth in Scotland or the Street of Messina between Sicily and Italy could contribute around 12000 MW to electricity production – which would render 12 nuclear power stations unnecessary!

‘Seaflow’ Generator, courtesy of MARE 25

The Irish coast has some of the highest wave energy density in the world, higher than many parts of Australia and America’s western seaboard. Current wave energy installations are mostly built into the shore and have the same environmental effect as other shore-based utilities. The majority of wave energy turbines produce from 75kW upwards but the development of smaller machines may also be viable. Work is in particular being carried out in providing energy for oil platforms. A development unit at Queens University has been at the forefront in wave energy research for the past 20 years. One of the world’s biggest manufacturers of wave energy machines is based in

28


Scotland and builds systems that have been placed worldwide. The biggest problem of wave energy generators is the unpredictability of waves – one day the sea is as flat as a pancake, the next you might be swept of your feet if you stand too close. In August 1995 the British wave energy machine ‘Osprey’ sunk due to too much wave action, without having produced even 1 kWh electricity.

So far only two wave energy generators have been installed for high production, one in Norway, the other on the Scottish island of Islay. Here, in November 2000 a more robust version of the ‘Osprey’ was connected to the mains. ‘Limpet’, a 500kW wave converter, sits snugly like its relative in the mollusc world on a rocky wall and uses the changing water levels to produce electricity. The generator consists of a hollow body, which opens below the water line. The rising water of a wave pressurises the air out of the

hoco

Inde1MDGre

‘Limpet’ supplies electricity to 400 households,picture courtesy of MARE 25

llow body through a turbine, the falling water sucks it back. The turbine is nstructed as such that it turns both ways.

2003 two English wave power developers plan on installing shoreline vices. Wavegen, already having a small device in Islay, are planning another W floating device for installation over the summer, while Ocean Power

elivery (OPD) plan their 750kW Pelamis device on a similar timescale. A new overnment-backed test centre on Orkney will provide useful testing sources to both developers.

The main UK wave power developers Wavegen

• Operated the 500kW Limpet shoreline oscillating water column on Islay since November 200

• Received a £1.67 million DTI grant to test a 1MW floating device off Orkney in summer 2003, also based on oscillating water column

• Expects to receive a further £2.3 million for the first of three devices to be installed off the Western Isles

• Hopes to install “hundreds of MW” by 2010, mostly later in the decade • Predicts initial costs of 4p/kWh for a floating device, falling to 2.7p/kWh over

ten years

Ocean Power Delivery • Proposes 150-metre long Pelamis seasnake device with several hydraulic joints

driving electric generators • Testing one-seventh scale model in the Firth of Forth, using £700,000 of DTI

grants • Hopes to test full-scale prototype in Orkney in summer 2003 • First commercial development, planned for 2004-2005, could be in UK or

Canada • Intends to install “several hundred MW” of wave devices off the UK by 2010 • Predicts costs of 2.4-4.3p/kWh for a 25MW installation by 2010

29


Orecon • Multiple oscillating water column device on buoy • Consortium of Plymouth University, fabricator Cornish Steel, marine

engineers Plimsoft, and German turbine manufacturer IBK • Completed one-year trial off Plymouth Sound funded by £292,500 EU grant

and £49,800 DTI grant • Plans a 10MW array by 2006 “if all goes well” • Hopes to build a 100MW array by 2015, possibly before 2010 • Predicts cost of about 5p/kWh

The main UK tidal stream developers Marine Current Turbines

• Shareholders include Seacore, IT Power, Bendalis Engineering and Corus UK

• Use twin turbines mounted either side of a pile driven into the sea bed • 300kW prototype to be installed off north Devon by November using £1.6

million in UK and EU grants • Intends to develop a 700 kW prototype by 2004 and a tidal farm of four

1MW devices by 2005, leading to 100MW of installed capacity by 2008 and 300 MW by 2010

• Predicts costs of 4.5-6.0p/kWh by 2005, eventually reducing to 3p/kWh • London Electricity has invested £3.5 million in the company

The Engineering Business • Stingray device converts tidal flows into an oscillating motion via hydrofoils

attached to an extendable arm • Installed a single hydroplane prototype (not connected to grid) off Shetland

in September 2002, using DTI grant of £1.1 million • Intends to build a 5MW cluster of 5 to 10 devices by 2004/2005 • Deliberately vague cost predictions of 4-14p/kWh

Tidal Hydraulic Generators • Companies involved include pump and turbine manufacturers Gilbert

Gilkes and Gordon, and Bennet Associates which contributed on hydraulic design

• A rig of turbines hydraulically pump fluid to a central underwater generator• Received a £50,000 grant from the Welsh Assembly for barge-based testing

of turbine design off the Pembrokeshire Coast in 2001 • Due to install 3kW test rig on sea floor by early October 2002, using further

£22,950 grant • Intends to build a generating station of fifty 1MW rigs at an undisclosed site off

Wales before 2010. Expects to receive a DTI grant shortly • Expects costs to be around 4p/kWh

Source: ENDS Report No 332, September 2002, p.28ff

30


In Ireland, the Marine Institute and Sustainable Energy Ireland are currently jointly undertaking a consultation exercise with a view to building a consensus around a strategic approach to wave energy development in Ireland. This consultation exercise will run from November 2002 to February 28th 2003.


The farm is of course right on the coast in an exposed site. If wave energy systems develop enough in the coming years it might be of benefit to have a system in place on the shore below the holding tanks. Such a system would have negligible visual impact, as the farm would conceal it. The electricity generated could be used by the farm and excess sold to the grid. The development of small-scale systems like this may be a few years off yet, but will be possible.


Not applicable as the farm is inland.


Wave energy may have a lot to contribute to this farm in the future. The high-energy costs make large-scale projects such as a wave energy turbine more viable. Again because of the farm location the turbine would not have any visual impact and could be recessed in against the shore. Such systems are already used in desalination plants and on isolated islands, so the technology is proven. The cost would add a not insignificant amount to the already expensive project but payback could be within 8 years given the potential to sell to the local grid. Electricity is in short supply in coastal areas especially in the northwest of Ireland.

Wave energy offers real potential for coastal-based aquaculture facilities. The technological advances being made in this field should be keenly observed in the future. The University of Limerick has begun a major project assessing the potential of this technology in partnership with Japan.

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Water Powered Pumps There are two types of water powered pumps, which we will discuss in this section, Hydraulic Ram Pumps and High Lifter Pumps. Both types use the pressure of falling water to pump a percentage of that water elsewhere. These types of pumps are commonly used worldwide to fill cattle troughs and domestic water supplies in hilly areas. They have an advantage over electrically powered pumps in that they don’t suffer the same wear and tear, as well as operating during power shortages and cuts.

Hydraulic Ram Pumps use the inertia of moving water rather than water pressure to lift water to a higher elevation. The pump operates in a cycle as follows:

1. When the waste valve is opened, water flows from the source through the intake pipe and out the waste valve.

2. After a short time, the velocity of the flow is high enough to force the waste valve closed. The water, due to its inertia wants to continue past the valve and as the pressure increases it forces the check valve open allowing water into the air chamber, compressing the air bubble inside the chamber. It is this air bubble that will force the water out through the outlet pipe.

3. When the check valve opens the pressure surge is spent and the water will try and flow backwards, but the check valve closes again preventing this from happening. The water flows out through the outlet pipe.

4. The waste valve now opens again and the whole cycle starts again.

Water Inlet

Waste Valve

Air Chamber
1.
Check Valve

Outlet pipe

32

2.
3. 4.


The hydraulic ram can deliver around 4m3 of water/day, which is relatively small for aquaculture purposes. It can, however, deliver water to an elevation 100m above its source and is virtually maintenance free.

High Lifters can pump larger volumes of water than hydraulic ram pumps. They can move volumes of up to 200m3/day depending on the head. High lifters are also generally quieter in operation than hydraulic ram pumps. The high lifter uses head pressure instead of momentum in a downhill pipe. It uses a large volume of low-pressured water to pump a smaller volume of water at a higher pressure. A large piston acts with a smaller one to gain mechanical advantage. A collar inside the pump controls the inlet valve. As the pistons reach the end of their stroke, they contact this collar, pushing it until it directs a small amount of water to the end of the spool in the pilot valve, thereby shifting it and changing the direction of the water flow in the pump. The flow moves the two-way pistons in the opposite direction until they again contact the collar, which shifts the pilot valve again, and the process repeats itself. The high lifter has a number of advantages over the hydraulic ram pump including its ability to be used in low flow situations. It could possibly be used on trout farms with a high head for diverting water back through the system.

A High Lifter Pump

How applicable this technology is to aquaculture has yet to be seen and is certainly site dependent. However, the application of new pumping technology is something definitely worth keeping abreast of.

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SOLAR POWER "Following the sun, we left the Old World." Christopher Columbus

T he amount of solar energy, which reaches the earth’s surface each year, is around 20,000 times current global energy consumption. Whilst it is not practical to convert all of this to usable energy, if we could just convert a fraction of this solar radiation there would be no more energy problems.

Many people presume that our climate in the Northern Hemisphere is not suitable to solar power, yet in Ireland and the UK it is possible to achieve 1000kWh/annum per m2 of photovoltaic (PV) cells. In fact, the amount of solar energy that falls on the UK and Ireland every year is equivalent to more than 700 times our total electricity needs. Solar panels produce electricity all year round. They work best when the sun is at its brightest, but also produce electricity on cloudy days, in the winter, in the snow and even when it’s raining. There are two predominant methods of extracting energy from the sun, solar water heating and the use of photovoltaic cells.

D I D Y O U

K N O W ?

The German government

has invested £280 million

in solar power.

6

A Solar PV cell

Solar Water Heating In Ireland each square metre of south-facing roof receives around 1000kWh of solar radiation during a year. This means that the roofs of many of our homes, offices and buildings receive more energy from the sun in a year than we need to provide for heating and hot water. It is possible to provide most of our hot water

requirements from May to September and provide some pre-heating for the remaining months. Shellfish hatcheries are already well aware of the need for sunlight in growing algae, yet much of the water used is heated by gas or oil fired burners.

Solar water heaters are made up of collectors, storage tanks and, depending on the system, electric pumps. A solar water heating system consists of a solar collector situated on the roof of the

A Solar Collector situated in a garden

34


building or in a position to get full sunlight. There are basically three types of collectors: flatplate, evacuated-tube and concentrating. A flatplate collector, the most common type, is an insulated weatherproofed box containing a dark absorber plate under one or more transparent covers. Evacuated-tube collectors are made up of rows of parallel, transparent glass tubes. Each tube consists of a glass outer tube and an inner tube or absorber covered with a selective coating that absorbs solar energy well but inhibits radiative heat loss. The air is withdrawn (‘evacuated’) from the space between the tubes to form a vacuum, which eliminates conductive and convective heat loss. Concentrating collectors are usually parabolic troughs that use mirrored surfaces to concentrate the sun’s energy on an absorber tube containing a heat-transfer liquid.

Most commercially available solar water heating systems require a well-insulated storage tank. Some solar water heaters use pumps to recirculate warm water from storage tanks through collectors and exposed piping. This is generally to protect the pipes from freezing when outside temperatures drop to freezing or below. A system could pay

Solar collectors on roofs in a housing estate in Scotland

Solar Water Heating at Salmon Hatchery

At Rosewall Creek salmon hatchery and smolt unit in Canada, a solar heating system has been integrated with a conventional propane heating system. Groundwater is heated with solar energy and stored in two tanks (seen in picture). The warm water is blended with cool water or is heated by an auxiliary propane boiler to deliver constant temperature water (12-14oC) to the salmon. A heat exchanger is also used to reclaim heat from the effluent water. Energy cost savings run at €11,500 per year with a pay back time of 6 years. Source: CanREN, Natural Resources, Canada

35


for itself in 2-3 years and dramatically reduce your heating bill

thereafter. Whilst these collectors can be purchased they can also be made using standard materials. The recent surge in the number of swimming pools heated by solar water heating systems indicates the viability of heating large volumes of water using this type of energy.

Solar Electricity The most common form of solar power is in converting sunlight directly into electricity. This is achieved by the use of what are called photovoltaic cells (photo = light, voltaic = electricity; PV for short). When sunlight strikes a PV cell, electrons are dislodged, creating an electric current. Photovoltaic cells are made primarily of silicon, the second most abundant element in the earth’s crust, and the same

semiconductor material used for computers. When the silicon is combined with one or more other materials, it exhibits unique electrical properties in the presence of sunlight. Electrons are excited by the light and move through the silicon. This is known as the photovoltaic effect and results in dc electricity. PV cells power many of the small calculators and wristwatches in every day use. More complex systems provide electricity to pump water, power communications equipment, light homes and business and run

appliances. Because electricity is produced in the form of dc current it can be fed directly into a battery, as in the case of a calculator, or can be converted with an inverter into ac for powering mains fed appliances. Whilst solar power in temperate climates is often the most expensive of options for those seeking to convert to renewable energy, the cost of PV technology has fallen by 80% in the last ten years. PV cells are not only now cheaper but are far more efficient at converting sunlight into electricity. As with solar water heating systems the PV cells are situated facing south to absorb as

much sunlight as possible. PV cells are also very reliable. This stems from the fact that the first cells were used in space and had to

A PV array at an electricity generating station in California

A Solar powered navigation buoy

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be virtually maintenance free. Modules have no moving parts and a life expectancy of 20-30 years.

There are three basic categories of photovoltaic systems with several types in each category.

Crystalline silicon flat plate collectors are the most developed and prevalent type in use today. These include single crystal silicon and polycrystalline silicon that is either grown or cast from molten silicon and later sliced into its cell size. They are often assembled into a flat surface and no lenses are used.

Thin film systems are inherently cheaper to produce than crystalline silicon but are not as efficient at converting sunlight. They are produced by depositing a thin layer of photovoltaic material on to a substrate like glass or metal. This group includes amorphous silicon like the kind found in calculators and watches.

Concentrators use much less of a specialised photovoltaic material and employ a lens or reflectors to concentrate sunlight on the photovoltaic cell and increase its

output. They can be produced more cheaply due to the reduced amount of expensive PV material. However, they can only use direct sun, so they must track the sun precisely.

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A solar powered pump being used on a cattle farm

S O L A R G L O S S A R Y

PV – Photovoltaic, meaning

Light – electricity.

PV cell – The semiconductor

device that converts light into

dc electricity.

Module – A group of PV cells.

Array – A group of modules.

Solar Tracker – Device which

allows the panels to constantly

adjust to the suns position

gaining maximum sunlight.

Flat plate Array – A PV array

in which the incident solar

radiation strikes a flat surface

and no concentration of

sunlight is involved.

Fresnel Lens – A

concentrating lens, positioned

above and concave to a PV

material to concentrate light on

the material.

Insolation – The amount of

sunlight reaching an area,

usually expressed in watts per

square meter per day.


Solar power could be used on the farm to power a number of the appliances. A typical 75W panel can provide 70kWh per annum in our climate. Whilst this could be used to power something like the purification system, it is not efficient given the high capital cost and long payback time (A 75W panel costs in the region of €500). Solar water heating could be of advantage in keeping the purification tank at a constant temperature. Solar water heating would be of further benefit in a shellfish hatchery where algae is cultured and larvae raised at elevated temperatures. Commercial hatcheries already harness natural light in growing algae but this use of the sun’s energy could be greatly increased where solar collectors are installed.



It may be possible in a few years time to have aeration systems running off solar panels. Aeration systems are used mainly during the summer months when the panels are at their most effective. Solar collectors could also be used to heat the water in the hatchery. The growth and development of fish eggs and fry is intrinsically linked to water temperatures. Increasing the water temperature by just a few degrees using solar collectors could reduce valuable growing time leading to a more efficient hatchery operation. All hatcheries have roof areas on which the solar collectors could be placed.


Producing solar electricity is unlikely to greatly reduce the large energy bills associated with the recirc unit. Solar collectors could be used, however, as with the previous case study to increase water temperature. Water temperature is not only critical in such a unit for fish growth rate but also for the efficient operation of the biofilters where bacteria break down the waste compounds. Solar collectors are relatively cheap to construct and are virtually maintenance free. Again consideration of the use of solar collectors is better made at the design stage to greatly increase their effectiveness.

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OTHER ENERGY SOURCES

"Irrigation of the land with seawater desalinated by fusion power is ancient. Its called 'rain'." Michael Mc Clary

A

Number of energy sources, which are not as widespread in use as the ones previously mentioned but none the less have potential for use in aquaculture, are now addressed.

Bioenergy Bioenergy is the process of using biomass (plant and organic matter) to produce energy. Biomass has been used for lighting, cooking, and heating ever since humans first discovered fire. Today modern biomass generating plants can produce hundreds of megawatt-hours of electricity in a manner similar to generating electricity using fossil fuels. In essence, the fossil fuels are simply replaced with plant matter as a fuel source, creating a cleaner, renewable energy alternative.

The main sources of biomass for biopower are agricultural waste, forestry waste, municipal and industrial waste and energy crops. The waste produced each day by a pig for example would provide enough gas to boil 5 kettles of water!

There are at least three different types of biofuel systems:

Direct firing involves burning biomass (feedstocks) directly to produce steam. This steam is then captured and directed to spin a turbine that produces electricity. Alternatively the system can be just used to create hot water for direct use. Although direct-fired biopower systems produce air pollution emissions, they are cleaner than coal-fired power plants because they do not release sulphur dioxide, a key pollutant contributing to acid rain. Furthermore, bioenergy systems have nowhere near the global warming impacts of fossil fuel plants. They are referred to as carbon dioxide neutral, given that the plant material absorbs as much carbon dioxide during its life as is released when burned. This is a key element of the ethos of using biopower.

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Co-Firing is similar to direct firing except for the fact that biomass materials are burned in combination with a fossil fuel, most often coal, in a high efficiency boiler. This method is a step towards renewable energy but still relies on fossil fuels.

Gasification systems are different from the other two methods, in that high temperatures are used in an oxygen-starved environment to convert biomass into

gas (a mixture of hydrogen, carbon monoxide and methane). This gas can then be used to fuel a gas turbine or a modified IC engine, which turns an electrical generator. A system in use at the ECOS centre in Ballymena is an example of a gasification system where coppice willow is grown sustainably to provide biomass for a

The author examining a willow powered gasification system in use at the ECOS centre, Ballymena.

Biomass Technology on the Farm

With support from the Iowa Department of Natural Resources, Sunrise Energy Co-operative of Blairstown, Iowa, has developed a computer model and business plan for a hypothetical integrated energy farm. The energy farm uses by products from each of the farms endeavours. An ethanol plant is at the hub of the system, producing ethanol and heat, carbon dioxide and animal feed. The heat is used in an aquaculture facility for raising commercial fish such as Tilapia. High protein feed is fed to cattle. In turn, cattle produce manure that can fertilise the corn. Methane captured from the manure is used as a supplemental energy source for ethanol production. Integrated energy farm software is designed to be adaptable for any agribusiness and is available from Iowa Department of Natural Resources. Source: Energy Bureau, Iowa Department of Natural resources

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50kW CHP plant. The plant produces electricity and heat in a carbon neutral manner for use in the centre. A simpler gasification system often in use on smallholdings uses a methane digester to convert animal waste into methane for direct use.

Methane Digesters

Methane is a gas, which is produced by the anaerobic fermentation of organic matter. Methane is odourless as it is the associated Hydrogen Sulphide produced by rotting material that gives the distinctive smell (Bubbling this gas through Calcium Carbonate removes the Hydrogen Sulphide, gas companies then add an odour so leaking methane can be detected). Methane (CH4) has an octane rating of 110 and produces around 1,000 BTUs (British Thermal Units) of heat per cubic foot of gas. Methane is made with a methane digester, which breaks down animal wastes but isn’t as effective with bulky vegetable matter.

A digester is an insulated tank, which allows the waste product to break down in the absence of oxygen and produce methane. The process takes from around 14-35 days depending on temperature. Digesters can operate in two temperature ranges depending on the bacteria involved in the digestion process.

TThe optimum temperature for mesophilic digestion is around 38oC (100oF), for thermophilic digestion around 55oC (130oF). The gas given off can be collected in a gas holder and used. Methane digesters are used world wide and run effectively if there is a good source of waste nearby i.e. pig slurry, chicken litter, cow slurry. They are currently being used for the digestion of solely fish offal in countries like Canada and the U.S.A.

A Digester at De Montfort University, Leicester

However, some plants emphasize the productiobiogas through the digestion process. Given the pIreland, sourcing animal waste should not poseIndeed it would be novel for slurry to be welcomalready several anaerobic digesters in Ireland.

Landfill sites are also a source of free methane operations are sited well away from landfill for obv

It may be possible to use compacted sludge frommethane digester. This could be of particular benef

41

Biotherm International, New Brunswick CA

n of liquid fertiliser instead of redominant agriculture sector in too many logistical problems. e on a fish farm, and there are

gas although most aquaculture ious water quality reasons.

fish farm effluents to power a it in high load recirculating units


farming species such as eels. The resulting methane could be used to heat water giving higher growth rates, or generate electricity to offset energy costs involved in the pumping. One of the main reasons that methane digesters are not yet commonly found in Ireland is the high capital investment necessary for the setting up of a viable unit.

At De Montfort University in the UK, the Applied Sustainable Technologies group has built a digester, which utilises pig slurry. 8 m3 of pig waste is added per week, which gives up to 1.5m3 of biogas each hour. The gas is held in a bag before being used in a CHP unit. At its height the unit can give 40kW of electricity running on 20m3 of gas/hour. This type of unit would pay for itself in 3-5 years and would be suitable for a high load facility like a recirculation unit. A biogas bag at De Montfort University

Biopower use is very popular in China and India and is slowly gaining acceptance as a competitive form of energy production in the United States.

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Hydrogen Power The use of hydrogen power may seem like something confined to sci-fi films and NASA, but the potential is now right on our doorstep. Hydrogen power has also been associated with weapons of mass destruction but thankfully efforts these days are on adapting hydrogen power to everyday energy production. Hydrogen power in this context does not refer to splitting its atom but using hydrogen gas as an energy source.

One of the benefits of using hydrogen power in the aquaculture industry is that a by-product is pure oxygen. Hydrogen and oxygen can be produced from water using electricity with an electrolyser. Making and storing oxygen and hydrogen is not kid’s stuff, remember it literally is rocket fuel. Although electricity is used to generate the fuel this can be supplied from any of the sources we have already discussed such as wind or sun.

The basic principle in producing hydrogen is that an electrolyser separates the hydrogen and oxygen atoms in water molecules. Two clusters of nickel electrode plates act as an anode and cathode. When placed in water and an electrical current is passed through, the larger hydrogen bubbles escape from the negative electrode (cathode) and the smaller oxygen bubbles evolve from the positive electrode (anode). The bubbles are kept separate and pass through purifiers. The resultant gas is then stored.

A theoretical 1kW electrolyser can produce 1m3 of hydrogen and 0.5m3 (500 litres) of oxygen in around 6 hours. The fuel, water, is of course pretty handy to come across on a fish farm, and although the technology in producing hydrogen hasn’t been fully utilised yet, many of the large petroleum companiesresearch for hydrogen powered vehicles for use when their

Principle of

Fuel In

EAnode

Depleted Fuel Out

H2

43

Load

have spent millions in oil supplies run dry.

an electrolyser

Oxidant In

lectrolyte Cathode

Depleted Oxidants Out

H2O

O2

H+


GEOTHERMAL POWER Geothermal power is another energy source, which we are not too familiar with in Ireland. The geothermal resources of Iceland and Hawaii are well known and utilised heavily in those countries for a myriad of uses including aquaculture. There are also geothermal resources in Ireland. The geological department of UCC has conducted numerous tests on geothermal water in a hidden valley underneath the city of Cork. The water is some 4oC warmer then normal groundwater and they are now examining the possibility of harnessing this heat in new buildings in the city.

The “Blue Lagoon”, Iceland with a geothermal power plant in the background

There are approx. 29 geothermal springs in Ireland where warm water has risen through faults in the earth’s crust. The temperature of these springs ranges from 13-22oC. A spring in Mallow comes to the surface at 20oC and is used to heat the local swimming pool. The system is essentially an open loop system in that water is pumped from the spring to an internal heat exchanger. In Dublin buildings in the east end of Trinity College are heated by heat pumps drawing on 12oC water beneath the bedrock. The energy saving is estimated at 2GWh/annum. Cities and large towns are thought to add up to 3oC to the temperature of their underground water through heat transfer. Ireland is currently part of an EC THERMIE project entitled the ”Promotion of the use of Geothermal Energy from proven Aquifers and matching of this energy to existing or potential heat users.”

Aquaculture has long realised the importance of tapping into groundwater supplies given the constant temperature and sterility of the water. Imagine if a facility could access water at 15oC all year around. Heating and energy costs would be dramatically reduced and growth rates optimised.

The geothermal resource in Ireland exists due to the effects of the ice age, retreating glaciers raised sea levels and flooded river valleys. Geothermal energy is also found in the form of geopressured brines. These brines are hot pressurised waters that contain dissolved methane and lie at depths of about 3km to

more than 6 km. Exploiting this resource is somewhat more of a challenge!

The Spa House Mallow

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Environmental Considerations "Global warming is no longer a distant threat, it’s as real, as clear and present an issue, with profound effects on peoples lives, as war and peace or recession and poverty – and the effects are only just beginning to be felt." Al Gore

We all use electricity but rarely stop to think about how it is generated and the impact it has on the environment. Without the exploitation of fossil fuels over the past 200 years the rise of the Western

economies and societies would not have been possible. However, burning fossil fuels, such as coal, oil and gas, lies at the heart of global climate change, acid rain and other more localised pollution problems. Experts such as the Intergovernmental Panel on Climate Change (IPCC) have predicted that the average temperature around the world will increase by between 1 and 3.5 degrees Celsius by 2100, a rate of warming greater than at any time over the last 10,000 years. Action needs to be taken to prevent this climate change, and the combustion of fossil fuels should be the first aspect to consider, as it accounts for about 85% of global CO2 emissions. The consequences of the Kyoto Protocol are probably the most important driver for the use of renewable energy now and for the foreseeable future.

The majority of electricity produced in Ireland and the UK is coal, oil and gas powered with use of turf and hydropower as well. Apart from hydropower, which is renewable, all these other methods of producing electricity have a profound effect on our environment. As the world warms, the climate in the UK and Ireland will change. Without major changes it is estimated that by 2020 the climatic zones in the UK will shift 200km northward. This means a northward shift of natural habitats, wildlife species and farming zones by about 50-80km per decade! There will be an average temperature increase of 1 degree and annual precipitation will increase by 5%, leading to more droughts in the drier southeast and flooding in the wetter northwest. Though these changes might benefit some industries, such as tourism, the changes for others such as aquaculture could have adverse effects, e.g. on water resources. Currently, the UK and Ireland are blessed with the warm effects from the Gulf Stream.

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Changes in water currents could lead to the disappearance of the Gulf Stream and leave Ireland and the UK in a weather system more akin to Newfoundland than the Mediterranean. This precarious position makes Ireland and the UK particularly vulnerable to sudden climate changes.

Carbon dioxide is only one of the by-products from burning fossil fuels. Nitrogen and sulphur dioxide contribute to the problem of acid deposition causing forests to die, lakes to become acid, as well as widespread damage to upland landscapes. These pollutants also lead to health problems for humans. Research on the impact of pollutants linked to fossil fuel burning suggests that breathing urban air costs each city dweller, on average, a year from their lives. Additionally the problem of resource depletion has to be considered. Estimates show that every year as much oil is used as it takes nature to create in 1 million years.

Ireland and the UK are prime locations for developing renewable energy generation such as wind or wave power. The UK wind resource is 28 times larger than that of Denmark, though only six times bigger in size. However, Denmark is far ahead in producing electricity through wind, having set a target of supplying 10% (1500MW) of its total demand by 2005 as part of a total renewable energy target of 12%. The UK currently produces only 0.25% of its electricity from wind, but it could reach a target almost twice as high as Denmark’s.

As we have shown, wind is not the only renewable energy source, and even with Ireland’s climate solar power is a significant resource. There is large scope for using photovoltaic cells, and examples such as roof-mounted PVs in Berlin suggested that 30% of the city’s current electricity needs could be met from this source. ‘Solar shingles’ have been developed in Michigan, USA by Energy Conversion Devices. 100 times thinner than traditional solar panels, they are easily installed on roofs at an estimated half the prize of conventional PVs.

The methods described in this report show the utilisation of renewable energy in a sustainable and environmentally friendly manner. Hydropower, which is the most controversial of renewable energy sources, only has an impact with large-scale operations and these are not the type for consideration by an aquaculture farm. Aquaculture operations are only too aware of environmental concerns and have strived in the recent past to improve the image of the industry. Aquaculture is amongst the most stringently policed industries, and licensing is the strictest in any food production sector. The positive environmental image that coincides with the use of renewable energy furthers the claim of aquaculture to be one of the greenest food producing operations in the world. It is one further step into an even greener future and wider public acceptance of the sector.

Using renewable energy reduces greenhouse gas emissions contributing to a healthier environment. Renewable energy provides the sustainable platform for energy production in the future.

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T H E P O T E N T I A L F O R R E N E W A B L E E N E R G Y U S A G E I N A Q U A C U L T U R E 9 Conclusion "We want to inherit a clean earth. Why shouldn’t we be allowed to live as you did when you were little?” Children’s Conference Bergen 1990

Renewable energy is not a quick fix for any aquaculture operation. It will not reduce your energy costs and supply all the electricity you need without a great deal of planning, patience and time. Most renewable energy technologies are installed by individuals or companies with a passion for

striving to help the environment in the long term.

We have seen that certain technologies lend themselves to different sites and aquaculture operations. The pacific oyster farm has low energy usage and therefore low electricity costs. Ensuring that the premises and equipment are efficient may reduce the energy bill by 10%, which is more than any renewable technology could do at present on the farm. A small wind turbine or solar collector may reduce costs further. Marine base shellfish hatcheries may benefit further by using solar collectors for their warm water needs.

The Rainbow Trout farm is unlikely to benefit from solar electricity until PV units become more effective. The farm could benefit by using solar collectors to heat the water for its hatchery or even fry. The largest potential lies in the utilisation of hydropower given the volume of water available on site. Whether one turbine or a series of smaller turbines is more effective depends entirely on site and energy requirements.

The marine recirc facility has by far the greatest energy demand and usage. Wind and wave power may be viable given the operating cost of energy per annum. The installation of such systems requires a large capital outlay but this can be recouped within a period as short as 6 years.

A characteristic of natural sources of energy is that they lend themselves much more to small-scale use than to large-scale exploitation. In this context renewable energy has many applications in aquaculture. As with all these methods, the fuel is virtually free. It is the initial capital cost that puts most people off developing renewable energy systems. Capital costs have however been reduced by up to 50% in the past 10 years and continue to fall. The use of hybrid systems could be considered in each of the case studies, using two or three different methods such as solar, hydro and wind power. Small wind/solar hybrid systems may compensate for seasonal variations in wind and sun availability each year to some extent.

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The employment of renewable energy sources on aquaculture sites needs to be thoroughly assessed for its suitability in each particular situation. Renewable energy will be more attractive in remote locations with some distance to the nearest electrical infrastructure. An economic analysis needs to compare the cost of connection as well as the use of alternative sources such as RE or diesel generation. It is also important to consider the consequences of power outages and to ensure that a facility is not totally relying on an intermittent renewable energy source and that a back up is accessible.

Renewable energy development is here to stay given the government’s commitment to the Madrid declaration, the Kyoto Protocol and AER. To support the implementation of the government’s sustainable energy policy by Sustainable Energy Ireland (SEI) funding provisions of €222m have been made in the National Development Plan. Sustainable Energy Ireland promotes and assists economically and environmentally sustainable production, supply and use of energy in Ireland. Under the government’s policy, SEI have established a €16.25m programme supporting research, development and demonstration of renewable sources of energy and related sources. A strategy detailing the objectives, content and priorities for this programme is available at www.irish-energy.ie, along with a Call for Proposals Information Pack.

Whether renewable energy has a role to play in aquaculture in Ireland is still up for discussion. Implementing renewable energy sources in aquaculture operations could be used as very positive PR to improve the public image of aquaculture. Promoting a ‘green’ image can have considerable benefits. If nothing else, however, aquaculture installations should strive to be energy efficient and thus reduce costs, saving money and increasing profit.

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http://www.irish-energy.ie/

T H E P O T E N T I A L F O R R E N E W A B L E E N E R G Y U S A G E I N A Q U A C U L T U R E 10

Useful Contacts

Agores, the European Commission’s Website for Renewable Energy Sources, Website: http://www.agores.org Overview of renewable energy including section on global warming. Airtricity National Management Centre, Clonard, Sandyford, Dublin 16, Tel: 01 2130400, Fax: 01 2130444, Webpage: http://www.eirtricity.ie, airtricity is a joint venture between Future Wind Partnership and NTR. Future Wind Partnership was set up with its aim being to develop Ireland's wind energy resources. American Wind Energy Association, 122 C Street, N W Fourth Floor, Washington DC 20001, USA. Tel. +1 202 383 2500, Fax, +1 202 383 2505. Email. [email protected] Website: http://www.econet.org/awea An umbrella organisation for the American wind industry. Ark Nursery, Burdatien, Clones, Co. Monaghan, Tel: 047 52049, Fax: 047 52295, Website: www.ecoflo.ie. The authors would like to thank Marcus McCabe for kindly providing the windmill photograph for the CD cover. Bord Gáis, Webpage: http://www.bge.ie Bord na Móna, Bord na Móna Plc., Main Street, Newbridge, Co Kildare, Ireland, Tel: 045 439000, Fax: 045 439001, Webpage: http://www.bnm.ie CADDET- Energy Efficiency, Webpage: http://www.caddet-ee.org/index.php CADDET stands for Centre for Analysis and Dissemination of Demonstrated Energy Technologies. It is an international information network that helps managers, engineers, architects and researchers find out about renewable energy and energy-saving technologies that have worked in other countries. Centre for Alternative Technology, Machynlleth, Powys Sy20 9AZ. Tel. (01654) 702400, Fax. (01654) 702782. Email. [email protected] Website: http://www.cat.org.uk An excellent source of information on all types of renewable energy. Publish information booklets and hold training weekends.

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http://www.agores.org/

http://www.eirtricity.ie/

mailto:[email protected]

http://www.econet.org/awea

http://www.ecoflo.ie/

http://www.bge.ie/

http://www.bnm.ie/

http://www.caddet-ee.org/index.php


http://www.cat.org.uk/


Centre for Biomass Technology, http://www.videncenter.dk/uk/index.htm Danish information network, which, amongst other things, disseminates information to interested parties in Denmark and around the world about Danish experiences in bioenergy. Specificly the Centre works with solutions to problems in the energy sector both related to technology, economy and environment. Centre for Sustainable Technologies, University of Ulster, Jordanstown, Newtownabbey, BT37 OQB, Northern Ireland. Email: [email protected] Website: http://www.engj.ulst.ac.uk Information on the activities of the centre for sustainable technologies including solar energy. CODEMA City of Dublin Energy Management Agency, Guinness Enterprise Centre, Unit 32, Taylors Lane, Dublin 8, Ireland, Tel: + 353 (0)1 410 0659, Fax:+ 353 (0)1 410 0576, Website: http://www.codema.ie Cork City Energy Agency, The Lord Mayors Pavilion, Fitzgeralds Park, Mardyke Walk, Cork, Tel/Fax: +353 21 363749, Website: http://www.corknrgy.com/ The main aims of the agency include promoting rational use of energy in all sectors of Cork city and encouraging the development of renewable energy. The targeted sectors are the domestic, transport, industrial/commercial and schools sector. CREST Centre for Renewable Energy Systems Technology, AMREL, Loughborough University, Loughborough, Leicestershire LE11 3TU, Tel: +44 (0) 1509 223466, Fax: +44 (0) 1509 610031, Webpage: http://www.lboro.ac.uk/departments/el/research/crest/index.htm Run an MSc in Renewable Energy Systems Technology. Danish Wind Industry Association, Vester Voldgade 106, 1552 Copenhagen V, Denmark, Tel: +45 3373 0330, Fax: +45 3373 0333, Webpage: http:// www.windpower.org/core.htm Information includes a guided online tour on windpower.

Danish Wind Turbine Manufacturers Association, Website http://www.windpower.dk An excellent site for up to date information on wind technology. Department of Transport, Sustainable Energy Division, 44 Kildare St, Dublin 2, Tel: 01 6041282, Wepage: http://www.irlgov.ie/tec/energy/renewable/ ECOS – Millennium Environmental Centre, Kernohans Lane, Broughshane Rd, Ballymena, BT43 7QA., Northern Ireland, Tel. 028 25 664400. Electricity Supply Board, Lr. Fitzwillam St, Dublin 2, Ireland. Tel 1850 372 372.Website: www.esb.ie , Email [email protected] Energy and Environment Research Unit, Faculty of Technology, The Open University, Milton Keynes MK7 6AA UK, Tel: +44 (0)1908 653335, Fax: +44 (0)1908 858407, Webpage: http://technology.open.ac.uk/eeru/

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http://www.engj.ulst.ac.uk/

http://www.codema.ie/

http://www.corknrgy.com/

http://www.lboro.ac.uk/departments/el/research/crest/index.htm

http://www.windpower.org/core.htm

http://www.windpower.dk/

http://www.irlgov.ie/tec/energy/renewable/

http://www.esb.ie/


http://technology.open.ac.uk/eeru/


Energy Saving Trust, Contact through Belfast Energy Efficiency Advice Centre, 1-11 May Street, Belfast BT1 4NA, Tel: 02890 240 664, Fax: 02890 246 133, Email: [email protected]; Webpage: http://www.est.org.uk The Energy Saving Trust (EST) was set up after the 1992 Earth Summit in Rio de Janeiro, to help reduce CO2 emissions in the UK. It is a non-profit organisation funded by governments and the private sector. European Wind Energy Association, 26 Spring St, London W2 1JA. Tel. (0171) 402 7122, Fax. (0171) 402 7125. Website: http://www.ewea.org Evans Engineering, Trecarrell Mill, Trebullett, Launcester, Cornwall, PL15 PQE, UK. Tel. (01566) 782255, Fax. (01566) 782793. Email: [email protected] Suppliers of micro hydro systems, design and advice. Galeforce Wind Turbines Ltd., Unit P8 Enkalon Ind Est, 25 Randalstown Rd, Antrim, BT41 4LD. Tel. (028) 94 464301, Fax. (028) 428835. Email: [email protected] Website: http://www.galeforce.nireland.co.uk Agents for the Fortis range of wind turbines. GB Windpumps, 22 Innox Hill, Frome, Somerset, BA11 2LW, UK. Tel. (01373) 454633. Email: [email protected] Install wind pump systems. Gilbert Gilkes & Gordon Ltd., Canal Head, Kendal, Cumbria, England LA9 7B2. Tel. +44 (0) 1539 720028, Fax. +44 (0) 1539 732110. Website: http://www.gilkes.com Suppliers of micro hydro systems. Grundfos Pumps Ltd, Unit 34, Stillorgan Industrial Pk, Blackrock, Co. Dublin. Tel. (01) 2954 926. Suppliers of solar powered pump systems. Home Power Magazine, 312 North Main St, Phoenix, Oregon 97535, UUSA. Tel +1 541 512 0201, fax. +1 541 512 0343. Website: http://www.homepower.com An excellent magazine and website with downloadable articles on building your own renewable energy systems. Institute of Energy and Sustainable Development, De Montfort University, Scraptoft Campus, Leicester LE1 9BH, UK, Tel: +44 (0)116.255 1551, Fax: +44 (0)116.255 0307, Webpage: http://www.iesd.dmu.ac.uk/index.htm Run an MSc Course on Climate Change & Sustainable Development. Irish Bioenergy Association, Education Centre, Church St., Cahir, Co. Tipperary, Tel: 052 43090, Fax: 052 43012, Webpage: http://homepage.eircom.net/~tippenergysal/IrBEA/ The aim of the association is to promote biomass as an environmentally, economically and socially sustainable indigenous energy resource and also promote its non-energy related benefits.

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http://www.est.org.uk/



http://www.galeforce.nireland.co.uk/


http://www.iesd.dmu.ac.uk/index.htm

http://homepage.eircom.net/~tippenergysal/IrBEA/


Irish Wind Energy Association, Arigna, Carrick-on-Shannon, Co. Roscommon, Ireland. Tel.(078) 46229, Fax. (078) 46016. Email. [email protected] Produce quarterly newsletter In the Wind. Marlec Engineering Products Ltd. Tel. (01563) 543020. Website: http://www.marlec.co.uk Manufacturer of small wind turbine systems. Mayo Energy Agency; Unit 1, The Quay, Ballina, Co Mayo, Tel: +353 96 74034, Fax: +353 96 72950, Website: http://www.hompage.eircom.net/~mayonrg Met Eireann, Glasnevin Hill, Dublin 9, Ireland. Tel. (01) 8064200, Fax. (01) 806 4247. The Irish Meteorological Service. Provide information on wind speed and sunlight hours for specific stations. Neale Consulting Engineers, 43 Downing Street, Farnham, Surrey, GU9 7PH, UK. Tel (01252) 722255, Fax. (01252) 737106. Email [email protected] Website: http://www.tribology.co.uk Design and install windpumps worldwide.

NEF Renewables- National Energy Foundation, Davy Avenue, Knowhall, Milton Keynes, MK5 8NG. Tel. (01908) 665555, Fax. (01908) 665577. Website: http://www.greenenergy.org.uk Information on all toes of renewable energy including micro hydro systems. Northern Ireland Electricity, 120 Malone Rd, Belfast BT9 5HT, Northern Ireland. Tel (028) 90661100, Website: www.nie.co.uk Pre-Cast Products Ltd, Ballindud, Tramore Rd, Waterford, Ireland. Tel. (051) 374048, Fax. (051) 371077. Agent for Poldaw windpumps. 3.5m and 5.0m Proven Engineering Products Ltd., Moorfield Industrial Estate, Kilmarnock, Ayrshire KA2 OBA. Tel. (01563) 543020, Fax. (01563) 539119 Manufacturers of wind turbines 600W to 6kW. Quasar Solar Electric Company, Screggan, Tullamore, Co. Offaly. Email: [email protected] Suppliers of PV systems.

Renewable Energy Office (N.I), 1 Nugents Entry, Off Townhall St, Enniskillen, Co. Fermanagh, BT74 7DF, Northern Ireland. Tel 048 66328269, Fax 048 66329771. Email: [email protected]. Renewable Energy Information Office, Contact: Irish Energy Centre, Shinagh House, Bandon, Co. Cork. Tel: 023 42193, Fax: 023 41304, Email: [email protected], Web: www.irish-energy.ie/reio.htm

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http://www.marlec.co.uk/

http://www.hompage.eircom.net/~mayonrg


http://www.tribology.co.uk/

http://www.greenenergy.org.uk/

http://www.nie.co.uk/




http://www.irish-energy.ie/reio.htm


Scoraig Wind Electric, Hugh Piggot, Scoraig, Dundonnell, Ross shire, Scotland IV23 2RE. Tel. (01854) 633286. Email. [email protected] Author of numerous books including the excellent It’s A Breeze! and Windpower Workshop. (Essential reading for those considering using windpower). Specialist in small scale wind turbine systems. Solar Sense, c/o The Environment Centre, Pier St, Swansea SA1 1RY. Tel. (01792) 371690, Fax. (01792) 371390. Suppliers of solar heating and electrical systems Solaris, Kilnarovanagh, Toames, Macroom, Co. Cork. Tel/Fax. (026) 46312 Suppliers of solar heating and PV systems. Solar Twin Ltd, 15 King Street, Chester, CH1 2AH, England, UK, Tel: +44 (0) 1244 403 404 Fax: +44 (0) 1244 403 654, Webpage: http://www.johnston.u-net.com/ UK based company selling domestic solar heating systems. Sonairte - National Ecology Centre, The Ninch, Laytown, Co. Meath, Ireland. Tel. (041) 9827572, Fax. (041) 9828130. Email: [email protected] A renewable energy park and ecology centre. Sustainable Energy Ireland, Shinagh House, Bandon, Co. Cork, Ireland. Tel (023) 42193,Fax (023) 41304. Website http://www.irish-energy.ie An excellent website and the first port of call for anybody interested in renewable energy. Numerous leaflets and explanatory booklets available on everything from hydropower to anaerobic digesters; free publications. Tipperary Energy agency Ltd, Education Centre, Church St., Cahir, Co. Tipperary, Ireland, Tel: 052 43090, Fax: 052 43102, Website: http://www.homepage.eircom.net/~tea/savenergy/ UK Solar Energy Society, c/o School of Engineering, Oxford Brookes University, Gipsy Lane Campus, Headington, Oxford, OX3 OBP. Tel. (01865) 484 367, Fax. (01865) 484 263. Email: [email protected] Website: http://www.brookes.ac.uk Information and facts on solar energy. Organise conferences on renewable energy. U.S. Department of Energy Photovoltaics Program. Website http://www.eren.doe.gov/pv/ Wavegen, 50 Seafield Rd, Longman Industrial Estate, Inverness, IV1 1LZ. Tel (01463) 238094, Fax. (02463) 238096. Website http://www.wavegen.co.uk World leaders in wave energy turbines. A good website for information on wave energy.

Wim Lunne. Website: http://www.geocities.com/wim_klunne/hydro/link.html Links to hydropower sites around the world. A great source of information.

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http://www.johnston.u-net.com/


http://www.irish-energy.ie/

http://www.homepage.eircom.net/~tea/savenergy/


http://www.brookes.ac.uk/

http://www.eren.doe.gov/pv/

http://www.wavegen.co.uk/

http://www.geocities.com/wim_klunne/hydro/link.html


World Power Technologies, 19 North Lake Avenue, Duluith, MN 55802, USA. Tel. +1218722 1492, Fax.+1 218 722 01791. Manufacturers of the Whisper range of wind turbines.

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Renewable Energy Report