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SUSTAINABLE ENERGY
Unit 2
Conventional Energy Sources
Conventional energy resources
• At present most of power generation is done by the conventional methods
• Fossil fuels is the important source• It may include solid (coal, wood or any biomass), liquid
(LDO, furnace oil), gaseous (natural gas, bio gas, LPG) fuel
• Sources for power generation are depleting in nature• Thermal, Nuclear and Diesel power plant comes under
this category• Efficiency for energy conversion is low• Pollution caused by the plant is very high• They are located far away from load centers• Transmission and Distribution losses are more
Energy source Strength Weakness Opportunities Threat
Electrical Direct Utilization Easy transportation No pollution Possibility of storage Versatile usage
Supply fluctuation Transmission &
Distribution losses Cost is high Low power factor
Continuous research to improve the efficiency
Other forms of energy resources
Stand alone systems
Should be converted to other forms of energy leads to low
Continuous depletion of resources
Frequent shutdown
Chemical Direct conversion to heat or electrical energy
Higher potential Low cost Waste heat recovery
Pollution to the environment
Depletion of the source
Reaction is difficult to control
Difficult in transportation
Need not depend on grid
Direct application is not possible
Decrease in market demand for the product
Nuclear Low quantity of fuel Efficiency is high Availability of the fuel
Hazardous radiation
High cost Maintenance
Improved technology for control fission
Safety
Handling of fuel and disposal of wastes is a major problem
Hydro Renewable Flexibility Free of cost Multiusage
Nature dependent Initial cost is high
Peak load High continuous
depletion of fossil fuels
Construction of storage units
Priority1. Power2. Agricultural
Comparison of various energy sources
Non-Renewable Energy Sources
• Conventional– Petroleum– Natural Gas– Coal– Nuclear
• Unconventional (examples)– Oil Shale– Natural gas hydrates in marine sediment
Disadvantages & Limitations Of Conventional Energy
* Resources are limited and may not be able to meet the increase future demand
* Emission of “Green house” gasses from thermal power stations
* Submersion of low lying areas in Hydel power* Consumption of fossil fuels towards transportation
of raw material i.e. coal for thermal power stations* Centralised power generation results in high losses
in transmission & distribution* De-forestation will have adverse effect on climate
change
Fuels Calorific Value Cost in Rs
Wood 12 MJ/kg 0.4/kg
Charcoal 20 MJ/kg 4/kg
Coal 30 MJ/kg 3/kg
Kerosene 40 MJ/kg 19/lt
Petrol 47 MJ/kg 32/lt
Diesel 44 MJ/kg 20/lt
Furnace Oil 42 MJ/kg 10/lt
LPG 80 MJ/kg 19/kg
Biogas 25 MJ/m3 0.50/m3
Electricity 3.6 MJ/unit 3/unit
Demand comparison of fuels
Demand comparison based on calorific value (100% efficiency)
Fuel Wood(kg)
CharCoal(kg)
Coal(kg)
Kerosene(kg)
Petrol(kg)
Diesel(kg)
FurnaceOil(kg)
LPG(kg)
Biogas m3
ElectricityUnit
Wood 1 0.6 0.4 0.3 0.25 0.27 0.28 0.15 0.48 3.33
Charcoal 1.66 1 0.66 0.5 0.42 0.45 0.47 0.25 0.8 5.55
Coal 2.5 1.5 1 0.75 0.63 0.68 0.71 0.37 1.2 8.33
Kerosene 3.33 2 1.33 1 0.85 0.90 0.95 0.5 1.6 11.11
Petrol 3.91 2.35 1.56 1.17 1 1.06 1.11 0.58 1.88 13.05
Diesel3.66 2.2 1.46 1.1 0.93 1 1.04 0.55 1.76 12.22
Furnace Oil 3.5 2.1 1.4 1.05 0.89 0.95 1 0.52 1.68 11.66
LPG 6.66 4 2.66 2 1.70 1.81 1.90 1 3.2 22.22
Biogas 2.08 1.25 0.83 0.67 0.53 0.56 0.59 0.31 1 6.94
Electricity 0.3 0.18 0.12 0.09 0.07 0.081 0.085 0.04 0.14 1
Demand comparison based on calorific value (Actual efficiency)
Fuel Wood(kg)
CharCoal(kg)
Coal(kg)
Kerosene(kg)
Petrol(kg)
Diesel(kg)
FurnaceOil(kg)
LPG(kg)
Biogas m3
ElectricityUnit
Wood(12%)
1 0.36 0.16 0.07 0.06 0.06 0.06 0.03 0.11 0.44
Charcoal(20%)
2.77 1 0.44 0.2 0.17 0.18 0.19 0.1 0.32 1.23
Coal(30%)
6.25 2.25 1 0.45 0.38 0.40 0.42 0.22 0.72 2.77
Kerosene(50%)
13.88 5 2.22 1 0.85 0.90 0.95 0.5 1.6 6.17
Petrol(50%)
16.31 5.87 2.61 1.17 1 1.06 1.11 0.58 1.88 7.25
Diesel(50%)
15.27 5.5 2.44 1.11 0.93 1 1.04 0.55 1.76 6.79
Furnace Oil (50%) 14.58 5.25 2.33 1.05 0.89 0.95 1 0.52 1.68 6.48
LPG (50%) 27.77 10 4.44 2 1.70 1.81 1.90 1 3.2 12.34
Biogas (50%) 8.68 3.12 1.38 0.62 0.53 0.56 0.59 0.31 1 3.85
Electricity(90%)
2.25 0.81 0.36 0.16 0.13 0.14 0.15 0.08 0.25 1
Non-Conventional Energy Sources
Renewable Energy Sources
• Source for power generation is not depleted• Wider application and utilization of nature• Mostly the energy is available at free of cost• Capital cost for power generation is high
– Solar energy– Bio energy– Wind energy– Tidal energy
Resources and Technologies of Renewable Energy
Solar Wind Biomass Small Hydro Waste to Energy: Municipal Solid / Liquid
Waste, Industrial Waste Bio Diesel OTEC (Ocean Thermal Energy) Wave Energy Geo-thermal energy Fuel Cell Technologies
Advantages of Renewable Energy Technologies
* Resources are everlasting
* No environmental concern problems
* Modular in nature
* No T & D losses
* Tailor made power generation system to cater to customer needs
Cumulative achievements as on 31.01.2009
No. Sources / Systems Achievements during 2008-09
CumulativeAchievements
I. Power From Renewables
A. Grid-interactive renewable power
1. Biomass Power (Agro residues) 77.50 MW 683.30 MW
2. Wind Power 998.85 MW 9755.85 MW
3. Small Hydro Power (up to 25 MW) 163.83 MW 2344.67 MW
4. Cogeneration-bagasse 232.90 MW 1033.73 MW
5. Waste to Energy 3.66 MW 58.91 MW
6. Solar Power 2.12 MW
Sub Total (in MW) (A) 1,476.74 MW 13,878.58 MW
B. Off-grid/Distributed Renewable Power (including Captive/CHP plants)
7 Biomass Power / Cogen.(non-bagasse)
60.92 MW 150.92 MW
8. Biomass Gasifier 8.98 MWeq. 160.31 MWeq
9. Waste-to- Energy 4.36 MWeq. 31.06 MWeq
10. Solar PV Power Plants and Street Lights
0.07 MWp 3.00 MWp
11. Aero-Generators/Hybrid Systems 0.09MW 0.89 MW
Sub Total (B) 74.42 MWeq 346.18 MWeq
Total ( A + B ) 1551.46 MW 14,224.76 MW
Potential of renewable energy sources in India
II.
Remote Village Electrification
300/NIL Villages/Hamlets 4254 villages + 1156 hamlets
III. Decentralized Energy Systems
12. Family Type Biogas Plants 0.66 lakh 40.90 lakh
13. Home Lighting System 31,754 nos. 4,34,692 nos.
14. Solar Lantern 27,360 nos. 6,97,419 nos.
15. SPV Pumps 7,148 nos.
16. Solar Water Heating - Collector Area 0.03 Mln. sq.m. 2.60 Mln. sq.m.
17. Solar Cookers 6.37 lakh
18. Wind Pumps 80 nos. 1347 nos.
IV. Other Programmes
19. Energy Parks 26 nos. 504 nos.
20. Akshay Urja Shops 15 nos. 289 nos.
MWeq. = Megawatt equivalent; MW = Megawatt; kW = kilowatt; kWp = kilowatt peak; sq. m. = square meter
Solar Energy
Sun radiates 180 billion MW of energy over the earth per day.
The three exclusive technologies for utilising solar energy are:-
Solar photovoltaic technology Solar Thermal technology Solar Passive architecture
Prehistoric trees captured Prehistoric trees captured energy from the Sunenergy from the Sun
Coal is the remains of prehistoric trees.
Solar Photovoltaic• This technology facilitates in converting the
solar energy into electrical energy and is being used for applications like
– Lighting
Solar Lanterns Solar Street Lights
Solar lanterns offer best alternative to kerosene lamps, gas lamps and conventional emergency lights.
Portable, light and suitable for use in both indoor and outdoor applications
Solar Lanterns provide opportunity to rural youth for establishing centralised charging system to charge set of lanterns and lease them on daily rental basis. They can also establish sales and service centres.
– Water pumpingSolar Pumps are useful for agriculture, horticulture and drinking water purpose.
They can draw water from open wells, bore wells and streams.
These systems functions during clear sunny days without any battery back-up.
Solar Water Pump System
– communication systems– Remote area villages
electrification– Telecom applications– Traffic signalling– Railway signalling systems etc.
SOLAR COLLECTORSSOLAR COLLECTORS
Solar thermal technology
The process involves utilising heat energy from solar radiation for heating, cooking, drying applications and power generation etc.– Solar water heating system
Flat Plate Solar Water Heating System
Vaccum Tube Solar Water Heating System
Solar flat plate collector model water heating systems consists of solar panels having collectors which have selective coated fins to absorb heat from solar radiation and transmitting same to water passing through the copper tubes attached to the fins. The water so heated is stored in an insulated tank making it possible to get hot water all 24 hours.These systems are available in capacities of 100 Litres per day (LPD) and in multiples of hundred to any capacity.
Are ideal to replace geysers in domestic and commercial sector i.e hotels, nursing homes, hostels etc., and also in industries as boiler feed water for pre- heating.
The manufacturing, installation and after sales service of these systems provide good opportunity for youth employment.
BiomassBiomass
Logs, twigs, straw, dung, leaves…..Logs, twigs, straw, dung, leaves…..
Bio-energy
Bio-gas & improved smokeless wood burning stoves are two important schemes being promoted by Ministry of Non-conventional Energy Sources, New Delhi in rural areas for conservation of the fossil fuels i.e. Firewood, kerosene, L.P.G etc.Bio-gasTwo models of bio-gas plants are being constructed.Low cost “Deenabandu” model for individual familiesFloating drum model bio-gas plant for community and institutional purposes.
The main raw material used for producing Methane gas in this bio-gas plant is animal waste (Dung). Bio-gas plants with kitchen waste and human excretion are also developed and also in use.
DEENABADHU MODEL BIOGAS PLANT
Biogas plants of family size, community / institutional capacities are available.
Methane gas produced in the biogas plant can be used primarily for cooking, lighting and running IC Engine to generate power or for mechanical application like water pumping running flourmill etc.
The Biogas plants can be constructed in rural areas for individual families who own sufficient number of cattle.
The slurry which comes as by-product from bio gas plant is rich in Nitrogen content than raw dung which is used as fertiliser in agriculture farms. Construction of bio-gas plant needs services of skilled masons and unskilled workers.
Manufacturing of bio-gas stove and other auxiliary equipment used in the system needs manufacturing facilities.
These activities help in generating employment for skilled and unskilled youth and also developing entrepreneurs who are engaged as specialised agencies in implementing the schemes.
Improved smokeless wood burning stoves
These models help in improving the thermal efficiency of wood burning stoves and also help in creating smoke free kitchen. They will also help in reducing the consumption of fire-wood and also, helping the children and women from eye and lung diseases caused due to smoke.
HYDRO-ELECTRICITYHYDRO-ELECTRICITY
Hydro energy
• Potential energy of the water• Potential energy totally depend upon the head of the
water stored• Storage of water is very essential for any hydro energy • Storage improves the irrigation and flood control
measures• It is renewable energy• Totally depend on the seasonal variation and
topographical of the land• Initial investment for generation of power is very high• Operating cost is negligible• Source is available only few geographical area far away
from load center
Hydroelectric Energy :
• Dams are the leading sours of this type of energy.
• Streams and rivers can also be used to produce electricity.
• Most cost efficient power available in the world.• Accounts for 6% of the world’s energy supply, or
about 15% of the world’s electricity.
Hydroelectric Energy (con’t) :
• The dam is placed on a river to store water in a reservoir. Water released from the reservoir flows through a pipe and into a turbine, which spins to drive a generator, Producing electricity. This type of energy uses gravity, and the natural flow of water, to push the water down the pipes to spin the turbines.
Hydroelectric Energy (Con’t) :
Wind Energy :
• Windmills are used to generate electricity as a source of renewable energy.
• The blades of a wind turbine form a rotor that captures wind energy.
• Energy increases with the height above the ground surface. Wind turbines are usually located on tall towers at least 100 feet above the ground.
Wind Energy
• There are numerous wind farms located around the world.
• In the United States they are mostly located in the central and western part of the US.
Wind Energy
Grid interactive power generation from Renewable Energy Sources in India
Estimated potential :
• Wind - 45,000 M.W.• Biomass - 52,000 M.W.• Co-generation - 5,000 M.W.• Mini Hydel - 15,000 M.W.• Municipal / Industrial waste - 5,000 M.W.
-------------------1,22,000
M.W.-------------------
Alternative Energy
What do we mean by Alternative Energy?
Bio Energy
Wind Energy
SolarEnergy
Fuel Cells
Electric Utilities
What is an alternative source of energy?
• An energy source that can be used instead of fossil fuels.
• It is usually a renewable source of energy that could be used should fossil fuels run out.
Why is there a need for alternative sources of energy?
• The graph that you completed last time shows just how much we rely on fossil fuels
• 90 per cent of the worlds energy supply’s come from fossil fuels
• Fossil fuels are convenient and relatively cheap – a litre of petrol in 1998 would have been 20p if there was no tax added!
How much longer can we depend on fossil fuels?
• Because they are fossil fuels they DO have a life expectancy
• “Oil has 40 – 50 years left”
• In 1960 they said this too! – what has happened is that we have found new reserves of oil and new technology has made the oil we use last longer
• Burning fossil fuels has increased atmospheric pollution.
• Vehicle exhausts contribute to acid rain more so than power stations burning coal.
• The carbon stored in fossil fuels is released as carbon dioxide when they are burnt – this leads to the green house effect and global warming
• Don’t get this confused with the hole in the ozone layer – this was caused by CFC’s
• Coal has the longest life expectancy
• Environmentalists dislike the burning of this fossil fuel the most as it gives off the most CO2
• Unless cheap alternatives to burning coal are found there is likely to be an increase in its use – especially from Asia which has a lot!
So what are the alternative energy sources to fossil fuels?
• Once upon a time – nuclear power was seen as the answer. Huge amounts of power could be produced from a small amount of uranium
• However, it was not well known that it produced radioactive waste
• The waste is dangerous to health and life for hundreds of years
• There is no secure place for storage.• Public confidence has also been shattered by the
explosion at Chernobyl in 1986
Bio-Fuels
• Outstanding potential when the price becomes competitive, and they may allow local availability to overcome (temporary) national fuel shortages!
• Some adjustments may be needed for certain boilers, and oil burners.
• Some potential exists for energy diversification in greenhouses and in transportation.
Biomass Energy (Con’t) :
• It is burned like fossil fuels, but it is renewable.• Biomass generates about the same amount of
carbon dioxide as fossil fuels, but every time a new plant grows, the CO2 is actually removed from the atmosphere. So in the end the net emission of CO2 will be about zero as long as plants continue to be replenished. (this is only in a perfect scenario)
• Wood is our biggest biomass energy source today.
Bio Fuel - Ethanol
The process is currentlyvery energyexpensiveand very inefficient
……....but somedaysoon…..…
Advantages of using natural sources of energy
• They are inexhaustible – they will always be available – they are renewable
• They are clean and will not damage the Earth
• There are several types – so one or more of them is present in each country
• Most natural sources can be used on a small scale and serve local needs therefore cutting costs of transmitting the energy
Biomass Energy :
• All non-fossil organic materials that have an intrinsic chemical energy content.
• Include: all water and land-based vegetation and trees, also virgin biomass, and all waste (MSW), municipal bio-solids (sewage) and animal wastes (manures), forestry and agricultural residues, and certain types of industrial wastes.
• Biomass is renewable because it only takes a short period of time to replace it unlike fossil fuels.
Ocean Thermal Energy Conversion (OTEC)
OCEAN ENERGY
• Ocean covers >70% Earth’s surface.
• Largest natural collector and storage system.
• Largest renewable energy resource.
OTEC• The ocean serves as a big storehouse of solar
energy.• In the tropical regions of the earth, the surface of the
water is heated by the sun, is at an average temperature of around 25ºC and at depths more than 100m, it is about 5ºC.
• The average difference in temperature of around 20ºC may be used in running a thermodynamic cycle to yield mechanical power, which in turn could be used to generate electrical power.
• Because of the very low temperatures involved, secondary working fluids such as Ammonia, Propane, R-12, having low boiling point are proposed to be used.
BOILER
WORKINGFLUID
COLD WATER
DEPTH IN
CONDENSER
WARM SURFACEWATER INT
G
TO OCEAN
FROM OCEAN
OTEC
OTEC (Ocean Thermal Energy Conversion)
OTEC utilizes T between warm shallow and cold deep ocean waters to run a heat engine.
OTEC Technology – Open cycle OTEC plant
OTEC Technology – Closed cycle OTEC plant
ENVIRONMENTAL DESIGN PARAMETERS
• Temperature & salinity vs depth
• Deep water wave characteristics
• Meteorological conditions
• Extreme water level
• Shallow water condition
• Deep ocean nutrient content
Advantages
• Collection and storage of energy is done by nature and hence costs nothing.
• This phenomenon of heating up of ocean water occurs through out the year and so continuous power supply may be assured.
• 100 MW OTEC plant prevents CO2 emission of 140,000 tonnes/year.
Disadvantages
• The very small temperature difference necessarily means thermo-dynamic efficiency of the order of 2 to 3%.
• The low level of efficiency in turn, call for handling large quantities of working fluid to obtain reasonable amount of power.
• The heat exchange boilers and condensers-become necessarily big and capital cost goes up.
• On-shore installations require long and big pipings, which add up to the cost. The proposal is therefore in favor of offshore installations using floating platforms.
• The material suggested for heat exchangers are titanium or alloy of copper and nickel, which are resistant to corrosion. But then, the cost adds up.
Applications
• Mineral extraction from seawater• Refrigeration and Air-conditioning• Desalined water(2 MW plant produces 4300 m3
of distilled water every day)• Deep water supported mari culture-rich
nutrients for aquatic systems.
TIDAL ENERGY
Tides
• Tide or wave is periodic rise and fall level of the sea
• Tides occur due to the attraction of seawater by the moon
• Tides contains large amount of potential energy, which is used for power generation
TIDAL ENERGY
*Form of water power that occurs in the ocean
* Converts the energy of tides into electricity
TIDAL ENERGY
* Renewable resource because it can be replenished
* Caused by the Moon’s gravity which will last a long time
TIDAL ENERGYTidal energy is theresult of the Moon’sGravitationalattraction on Earthand the way themoon’s gravity pullsthe oceans in abulge as the Moonorbits Earth – thetide must raise thewater at least 10feet
Tides Governed by Earth-Moon-Sun
Tidal changes in sea level occur as Earth rotates beneath bulges in ocean envelope, which are produced by solar and lunar gravitational forces and centrifugal forces
MOON’S ORBIT
North PoleEarth rotates counter-clockwise
Resource Variable but Predictable
Greatest range occurs when sun and moon
pull in same direction (spring tide)
Weakest when sun and
moon in opposition (neap tide)
Tidal Power Generation
Tides• When the water is above the mean sea level it is called
flood tide.
• When the water is below the mean sea level it is called ebb tide.
• At the time of high tide, water is at a high level and can be let into a basin to be stored at a high level there. The same water can be let back into the sea during the low tide through the turbines, thus producing power
• Since the basin water level is high and seawater is low, there is a differential head comparable to the tidal range, which can be utilized for the running of the turbines
Turning Tides into Usable Energy
• Ebb generating system• A dam (barrage) is built
across the mouth of an estuary.
• Sluice gates allow incoming tides to fill the basin.
• As the tide ebbs, the water is forced through a turbine system to generate electricity.
Types of TurbinesBulb turbine used at La Rance tidal plant on the Brittany coast in France
TIDAL ENERGY
TIDAL ENERGY
ADVANTAGES:
Renewable
Reliable and PredictableClean Energy
Alternative – Needs no Fuel
Water is Dense and Free
Advantages
– It is free from pollution, as it does not use any fuel.
– It is superior from hydropower plant as it is totally independent of rain.
– It improves the possibility of fish farming in the tidal basins and it can provide recreational facilities to visitors and holidaymakers.
Advantages
• Renewable • Abundant (estimated that it could produce 16% of
worlds energy.)• Pollution free (except during construction)• Relatively consistent (unlike wind that is
inconsistent and is highly concentrated in certain areas depending on the topography.)
• Water is a free resource• Presents no difficulty to migrating aquatic animals
(avoidable)
TIDAL ENERGY
DISADVANTAGES:
Limited use and can affect fish migration
Impact on shore line
Expensive parts
Disadvantages
• Tidal power plants can be developed only if natural sites available on the bay
• As the sites are available on the bays, which are always far away from load centers, the power generated has to be transmitted to long distances. This increases the transmission cost and transmission losses
• The supply of power is not continuous as it depends upon the timing of tides
• The navigation is obstructed• Utilization of tidal energy on small scale is not
economical
Disadvantages
• Disturbance/Destruction to marine life (effect wave climate that effects shallow/shore plant life)
• Expensive to construct (estimated 1.2 billion dollars.)
• Reliability (have not been around long so we do not know long-term reliability is.)
• Recreational costs (visual impact, sport fishing, swimming, etc.)
• Cost of Maintenance Higher• Power transmission from offshore facilities harder• Power quality (waves fluctuation)
TIDAL ENERGY
* Good Alternative Energy Resource for Future
Geothermal Energy
Sources of Earth’s Internal Energy
•70% comes from the decay of radioactive nuclei with long half lives that are embedded within the Earth
•Some energy is from residual heat left over from Earths formation.
•The rest of the energy comes from meteorite impacts.
Availability of Geothermal Energy • On average, the Earth emits 1/16
W/m2. However, this number can be much higher in areas such as regions near volcanoes, hot springs and fumaroles.
• As a rough rule, 1 km3 of hot rock cooled by 1000C will yield 30 MW of electricity over thirty years.
• It is estimated that the world could produce 600,000 EJ over 5 million years.
• There is believed to be enough heat radiating from the center of the Earth to fulfill human energy demands for the remainder of the biosphere’s lifetime.
• Geothermal production of energy is 3rd highest among renewable energies. It is behind hydro and biomass, but before solar and wind.
Modern Day
• Geothermal energy is used for:– heating of pools and spas – greenhouses and aquaculture facilities– space heating and district heating– snow melting – agricultural drying – industrial applications – ground-source heat pumps
How is geothermal energy created?
• Wells are drilled into the geothermal reservoirs
How is geothermal energy created?
• Steam, heat, or hot water from reservoirs spin the turbine
• Used water is returned down an injection well
Different Geothermal Energy Sources
Hot Water Reservoirs: As the name implies these are reservoirs of hot underground water. There is a large amount of them in the US, but they are more suited for space heating than for electricity production.
Natural Stem Reservoirs: In this case a hole dug into the ground can cause steam to come to the surface. This type of resource is rare in the US.
Geopressured Reservoirs: In this type of reserve, brine completely saturated with natural gas in stored under pressure from the weight of overlying rock. This type of resource can be used for both heat and for natural gas.
Normal Geothermal Gradient: At any place on the planet, there is a normal temperature gradient of +300C per km dug into the earth. Therefore, if one digs 20,000 feet the temperature will be about 1900C above the surface temperature. This difference will be enough to produce electricity. However, no useful and economical technology has been developed to extracted this large source of energy.
Hot Dry Rock: This type of condition exists in 5% of the US. It is similar to Normal Geothermal Gradient, but the gradient is 400C/km dug underground.
Molten Magma: No technology exists to tap into the heat reserves stored in magma.
Direct uses of geothermal energy is appropriate for sources below 1500C
• space heating• air conditioning• industrial processes• drying • Greenhouses• Aquaculture• hot water• resorts and pools• melting snow
Geothermal Power Plant
• It is also a thermal power plant, but the steam required for power generation is available in some part of the earth surface.
• According to various theories earth has a molten core. The fact that volcanic action takes place in many places in many places on the surface of earth supports these theories.
PIPESPUMP
CONDENSER
GENERATOR
TURBINE
STEAM TURBINE
SEPARATORCONTROLS
15,000m
UNDER GROUNDSTEAM STORAGE
(STEAM WELL)
Geothermal Power Plant
Working Steam Well : Pipes are embedded at places of fresh
volcanic action called steam wells, where the molten internal mass of earth vents to the atmosphere with very high temperatures.
By sending water through embedded pipes, steam is raised from the underground steam storage wells to the ground level
Separator: The steam is then passed through the separator where most of the dirt and sand carried by the steam are removed
Turbine: The steam from the separator is passed through steam drum and is used to run the turbine, which in turn drives the generator
The exhaust steam from the turbine is condensed The condensate is pumped into the earth to absorb the
ground heat again to get converted into steam
ADVANTAGES OF USING
GEOTHERMAL ENERGY
• Some advantages geothermal energy production provides over non-renewables– Clean
– Less land stress
– Reliable
– Stimulates Economy
Advantages Energy is continuously available and is more dependable It has a good potential among the non-conventional energy sources Capital and generation cost is the lowest compared to nuclear and
coal plants No solid pollutants and no radiation fall out Useful minerals, such as
zinc and silica, can be extracted from underground water. Geothermal energy is “homegrown”.This will create jobs, a better
global trading position and less reliance on oil producing countries. Geothermal plants can be online 100% - 90% of the time. Coal
plants can only be online 75% of the time and nuclear plants can only be online 65% of the time.
Geothermal electric plants production is 13.380 g of Carbon dioxide per kWh, whereas the CO2 emissions are 453 g/kWh for natural gas, 906g g/kWh for oil and 1042 g/kWh for coal.
Geothermal plants do not require a lot of land, 400m2 can produce a gigawatt of energy over 30 years.
Challenges
• High Price And Risky
• Discovering Heat Reservoirs
• Land Space to Create Plant
Disadvantages
• Gaseous effluent, especially Hydrogen sulphide, is a nuisance
• Ground subsidence may occur• Life span may be less compared with nuclear and coal
plants• The highly mineralized effluent may pollute ground water
and hence requires reinjection into well• Problem of corrosion of components due to salt• Thermal pollution due to effluent if not reinjected
Disadvantages Brine can salinate soil if the water is not injected back into the
reserve after the heat is extracted.
Extracting large amounts of water can cause land subsidence, and this can lead to an increase in seismic activity. To prevented this the cooled water must be injected back into the reserve in order to keep the water pressure constant underground.
Power plants that do not inject the cooled water back into the ground can release H2S, the “rotten eggs” gas. This gas can cause problems if large quantities escape because inhaling too much is fatal.
One well “blew its top” 10 years after it was built, and this threw hundreds of tons of rock, mud and steam into the atmosphere.
There is the fear of noise pollution during the drilling of wells.
Case Study• Simultaneous generation of heat and power based geothermal power
plant for the first time has been operated in Mecklenburg, Germany since 2003.
Principle• The plant uses Organic Rankine Cycle steam power units, which
works effectively at low temperatures.
Heat The thermal water is carried to the surface to feed the heat supply
using geothermal probes. This water is often mineralized, the salt content in thermal water is 220
g/l and is therefore not usually directly used. So it is fed through heat-exchangers to transfer the energy into the
district heating system, and then pushed back deep into the earth. Plant was designed for an annual output of 21,000 MWhr.
Power In addition to district heating, geothermal power plant is used for
generating power. Power plant is fed with hot water at 98°C from 2200m underground. Water transfers its heat energy via the heat exchanger to the turbine
circuit. It is relatively low temperature power generation, a synthetic organic
substance that boils at 31°C is used in the turbine. Geothermal power plant can supply over 500 apartments of 1400
MWhr/yr to cover electricity requirement of 74000 residents.
Magneto Hydro Dynamics (MHD)
INTRODUCTION
-- exerts a force (creates structure)
-- provides insulation
-- stores energy
(released in flare)
Magnetic Field Effects:
MHD• MHD power generation is a new system of electric power
generation, which is said to be of high efficiency and low pollution.
• In advanced countries MHD generators are widely used but in developing countries like India it is still under construction. This construction work is in progress at Trichy in Tamilnadu under joint effort of BARC (Bhabha Atomic Research Centre), BHEL, Associated Cement Corporation (ACC) and Russian technologies.
• As its name implies, Magneto hydro dynamics (MHD) is concerned with the flow of a conducting fluid in the presence of magnetic and electric field.
• The fluid may be gas at elevated temperature or liquid metal like sodium or potassium.
• An MHD generator is a device for converting heat energy of a fuel directly into electrical energy without a conventional electric generator
MHD
• MHD power generation uses the interaction of an electrically conducting fluid with a magnetic field to convert part of the energy of the fluid directly into electricity.
• MHD - the study of the interaction between a magnetic field and a plasma, treated as a continuous medium.
• Converts thermal or kinetic energy into electricity.
MHD
COMBUSTIONNOZZLE
GAS FLOW
GENERATORCHANNEL
D.CLOAD
ELECTRODESCHAMBER
Principles of MHD Power Generation
• The principle of MHD generation is simply that discovered by Faraday: When an electric conductor moves across a magnetic field a voltage is induced in it which produces an electric current.
• This is the principle of the conventional generator also, where a gaseous conductor, an ionized gas, replaces the conductors. If such a gas is passed at a high velocity through a powerful magnetic field, a current is generated and can extracted by placing electrodes in a suitable position in the stream. This arrangement as illustrated in the Fig provides DC power directly.
Conversion Efficiency
• MHD generator alone: 10-20%
• Steam plant alone: ≈ 40%
• MHD generator coupled with a steam plant: up to 60%
Losses
• Heat transfer to walls
• Friction
• Maintenance of magnetic field
MHD + Steam plant
Other uses of MHD Technology
• The “Yamoto” a boat built by Mitsubishi powered solely by MHD propulsion
• Can travel up to 15km/hr
Thermionic Energy Conversion system
Thermionic Energy Conversion system
• Another form of direct conversion of heat energy to electrical energy has been achieved in the thermionic converter. It utilizes the thermionic emission effect, that is, the emission of electrons from heated metal (and some oxide) surfaces.
• The energy required to extract an electron from the metal is an important parameter, known as the work function of the metal. Typical values of the order of a few electron volts. The value of the work function varies with the nature of the metal and its surface condition.
• In principle, a thermionic consists of two metals (or electrodes) with different work function is maintained at a higher temperature than one with the smaller work function.
Thermionic Energy Conversion system
Hot electrode(Emitter)
orCathode
Electrons
ExternalDC Load
Cold electrode (Collector) orAnode
Evacuatedvessel
EmitterCollector
Load
ElectronCurrent
Heat OutHeat In
Thermionic Energy Conversion system
• System consists of two electrodes held in a container filled with ionized cesium vapour. Heating one electrode, electrons are emitted, that travel to the opposite, colder electrode. The hotter electrode (or emitter) emits electrons (i.e. negative charges) and so acquires a positive charge, whereas the colder electrode (or collector) collects electrons and becomes negatively charged.
• A voltage (or electromotive force) thus develops, between the two electrodes and a direct electric current will flow in an external circuit (or load) connecting them.
• The voltage, which may be 1 volt (or so), is determined primarily by the difference in the work function of the electrode materials.
• Because electrons cannot travel far in air, thermionic converters require that the electrodes be in a vacuum. This limits the size of the converter so that only small-scale power production is feasible
Problems to be overcome
• Find material with high enough emission
• Space charge
Types of TEC
• Closed space diode
• Caesium diode
• TECs with auxiliary discharge
Some applications
•Electric vehicles•Topping cycle•Cogeneration•Solar cell•Domestic heating and electricity supply•In-pile system
Thermionic Energy Conversion system
Developments making TECs more feasible
•Advances in electronic emitter materials
•New methods of plasma analysis by computer simulation
•Application of microminiaturisation techniques
SUMMARY
Thermoelectric Energy Conversion System
Thermoelectric Energy Conversion
• Thermo-electric generator is a device, which converts heat energy (thermal energy) into electrical energy through semi-conductor or conductor.
• The direct conversion of heat energy into electric energy (i.e. without a conventional electric generator) based on the Seebeck Thermo electric effect.
• Consider two dissimilar materials joined together in the form of a loop so that there are two junctions.
Thermoelectric Energy Conversion
Hot junctionT
Material-1
Material-2
Cold junctionT
V
2 1
Seebeck Effect• In 1821, Thomas Seebeck found that an electric
current would flow continuously in a closed circuit made up of two dissimilar metals, if the junctions of the metals were maintained at two different temperatures.
S= dV / dT;
S is the Seebeck Coefficient with units of Volts per Kelvin
S is positive when the direction of electric current is same as the direction of thermal current
Thermoelectric Energy Conversion
• If a temperature difference is maintained between these two junctions, an electric current will flow round the loop. The magnitude of the current will depend on both the materials used and the temperature difference of the junction (ΔT = T2 -T1). If the circuit is broken an open circuit voltage ‘V’ appears across the thermals of the break as shown in figure.
• The thermo emf, V produced by the device is given by
V= S1-2ΔT S1-2 - Seebeck Coefficient.
Thermoelectric Power Generation
• Used in Space shuttles and rockets for compact source of power.
• Energy recovery from automobile engines
• Diffusive heat flow and Peltier effect are additive i.e. both reduce the temperature gradient.
Fuel Cells
Fuel Cells
• Electro-chemical device for the continuous conversion of a portion of the free energy change of a chemical reaction to electrical energy.
• It is distinguished from a battery in that it operates with continuous replenishment of the fuel and the oxidant at active electrode area and does not require recharging.
• Main component of a fuel cell are (i) a fuel electrode (ii) an oxidant or air electrode and (iii) an electrolyte
Introduction to Fuel Cells
• A fuel cell is a device that uses hydrogen (or hydrogen rich fuel) and oxygen to create electricity by an electrochemical process.
• If pure hydrogen is used as a fuel, fuel cells emit only heat and water as a byproduct.
• Current applications: power passenger vehicles, commercial buildings, homes, and laptop computers.
Why We Want to Use Fuel Cells?
• Environmental concern of using fossil fuel (e.g. poisonous emissions)
• Oil crises
• Global warming
• A fuel cell is a controlled chemical and electrical energy conversion device which continuously converts chemical energy to electrical energy.
• In a hydrogen, oxygen fuel cell electrochemical reaction involves the process of ionisation in which atoms or molecules looses or gains one or more electron.
• Loosing one electron gives the atom overall positive charge and gaining an electron gives negative charge.
• Water can be ionised into hydroxyl ion(-) and hydrogen ion(+) when two dissimilar metal electrodes like sodium, zinc, cadmium is placed in a solution containing ions. Voltage is developed between positively charged electrode.
• In fuel cell the reactants are continuously fed to the cell and electrically it is extracted.
• Therefore the fuel cell is like a storage battery but with regular supply of fuel and oxygen.
Anode Cathode
Fuel Cell
H2 O2
H+
Overall: H2 + ½ O2 H2O
½ O2 + 2H+ + 2e- H2OH2 2H+ + 2e-
Electrolyte
e-
Fuel Cell Components• Components
– Electrolyte (Membrane)
• Transport ions
• Block electrons, gases
– Electrodes
• Catalyze reactions
• Transport
– Ions, electrons, gases
• May be a composite
– (electro)Catalyst +
– Conductors +
– Pore former Membrane-Electrode Assembly (MEA)
electrolyte
catalyst
electrodes
sealant
Fuel Cells
• Some of the fuel cells are hydrogen, oxygen(H2O2), hydrazine (N2H4O2), Carbon/coal(C,O2),, methane (CH4,O2).
• Hydrogen, oxygen (Hydroxy) fuel cells, are efficient and highly developed.
• In the hydrox cell, catalyst is embedded in Nickel electrode.The electrolyte is typically 30% KOH because of its high electrical conductivity and it is less corrosive than acids.
• Cell reactions are,
Anode reaction : 2H2 4H+ + 4e-
Cathode reaction : 2H2 + O2 2H2O (vapour) + Energy
• H2 is fed to one electrode and is absorbed. It gives off free electrons and also reacts with hydroxyl ions of the electrolyte to form water.The free electrons travel towards oxygen electrode through the external circuit.
• The two electrons at the external circuit combine with one molecule of water to form 2OH- ions.
• These OH- ions migrate towards H2 electrode and are consumed there.
• The electrolyte remains invariant. The cell operates at or slightly above atmospheric pressure and at temperature of about 90ºC.These types of cells are called low temperature cells. In high-pressure cells pressure is upto about 45 atmosphere and temperature is upto 300ºC.
• A single hydrogen, oxygen fuel cell can produce an emf of 1.23 Volt at atmospheric pressure and at 25ºC.By connecting number of cells, it is possible to create useful potential of 100 to 1000 volts and power levels of 1 kW to nearly 100MW.
• The overall efficiency of the cell is the ratio of the power generated and the heating value of the hydrogen consumed.
Aspects PEMFC AFC PAFC MCFC SOFC
Type of electrolyte
H+ ions (With anion bound in
polymer membrane)
OH- ions (Typically
aqueous KOH solutions)
H+ ions (H3PO4
solutions)
CO32- ions (Typically
molten LiK2CO3
eutectics)
O2- ions (Stabilized ceramic matrix with
free oxide ions)
Typical construction
Plastic, metal or carbon
Plastic, metal Carbon, porous ceramics
High temperature metals, porous
ceramic
Ceramic, High temperature metals
Internal Reforming
No No No Yes, Good Temperature match
Yes, Good Temperature match
Oxidant Air to O2 Purified Air to O2
Air to enriched air Air Air
Operational Temperature
65 – 85 ºC 90 - 260 ºC 190 - 210 ºC 650 - 700 ºC 750 - 1000 ºC
Distributed Generation system level
(η %)
25 - 35 32 - 40 35 - 45 40 - 50 45 - 55
Primary contaminate sensitivities
CO,NH3 and
sulphur
CO,CO2 and
sulphur
CO < 1% sulphur Sulphur Sulphur
Comparison between different types of fuel cells
Types of Fuel Cell
• PEMFC – Proton Exchange Membrane Fuel Cell or
Polymer Electrolyte Membrane• AFC – Alkaline Fuel Cell• PAFC – Phosphoric Acid Fuel Cell• MCFC – Molten Carbonate Fuel Cell• SOFC – Solid Oxide Fuel Cell
Fuel Cell Choices
• Ambient Temperature
Rapid start-up
H2 or CH3OH as fuels
Catalysts easily poisoned
• Applications
– Portable power
– Many on/off cycles
– Small size
• High Temperature
Fuel flexible
Very high efficiencies
Long start-up
• Applications
– Stationary power
– Auxiliary power in
portable systems
Temperature sets operational parameters & fuel choice
How Fuel Cells Work
• A fuel cell is a device that uses hydrogen (or hydrogen-rich fuel) and oxygen to create electricity by an electrochemical process.
• A single fuel cell consists of an electrolyte sandwiched between two thin electrodes (a porous anode and cathode).
Types of Fuel Cells
• Polymer Electrolyte Membrane (PEM)• Phosphoric Acid• Direct Methanol• Alkaline• Molten Carbonate• Solid Oxide• Regenerative (Reversible)
PEM
• Also called SPEFC (Solid Polymer Electrolyte Fuel Cells)
• Use a proton exchange membrane as an electrolyte.
• Low temperature fuel cells (85-1050C)• Nafion® membranes (developed by DuPont)
consists of a polyterrafluoreethylene (PTFE) based structure
Polymer Electrolyte Membrane (PEM)
Alkali Fuel Cell• Electrolyte: KOH in H2O
– Liquid in a matrix, or liquid recirculated
• Mobile species: OH-
• Half cell reactions
– anode: H2 + 2OH- 2H2O + 2e-
– cathode: ½ O2 + H2O + 2e- 2OH-
• Catalysts
– anode: Ni, Ni-Pt, Ni-Co, etc.
– cathode: NiO, Ag, etc.
– unlike other fuel cells, rapid cathode kinetics, slower anode
• Features
– High power output due to rapid electrocatalysis rates
– Inexpensive materials
– Highly sensitive to CO2: KOH(aq) + CO2 K2CO3 (ppt)
– Used by NASA for manned missions
H2O available in electrolyte
Alkaline
Phosphoric Acid Fuel Cell
• Electrolyte: H3PO4 + H2O (~20%)
– Liquid in a SiC matrix
• Mobile species: H+
• Half cell reactions
– anode: H2 2H+ + 2e-
– cathode: ½ O2 + 2H+ + 2e- H2O
• Catalysts
– anode + cathode: Pt/Vulcan carbon
– Pt coarsens with time, phosphate adsorbs to surface
– like most fuel cells, slow cathode kinetics, faster anode
• Features
– Low power output due to slow cathode kinetics
– Expensive catalysts, and very high cost per power output
– Catalyst relatively insensitive to CO (due to high temp)
– “Commercialized” in 1990’s, then abandoned, now on again
Phosphoric Acid
Molten Carbonate Fuel Cell
• Electrolyte: K2CO3, Na2CO3, Li2CO3 eutectic liq (500-700°C)
– Liquid in a LiAlO2 matrix
• Mobile species: CO3=
• Half cell reactions
– anode: H2 + CO3= CO2+ H2O + 2e-
– cathode: ½ O2 + CO2 + 2e- CO3=
• Catalysts
– anode: Ni-Al, Ni-Cr alloys
– cathode: NiO
– like most fuel cells, slow cathode kinetics, faster anode
• Features
– High temperature in situ hydrocarbon fuel reforming
– Highly corrosive environment
– NiO dissolution at cathode & precipitation at anode as Ni
– Largely abandoned in the US, but Japan and Europe continue
CO2 recirculated
Molten Carbonate
PEM Fuel Cell• Electrolyte: Sulfonated, perfluorinated polymer [Nafion]
– “water–polymer composite”
• Mobile species: H(H2O)n+ [not H+]
• Half cell reactions
– anode: H2 + 2nH2O 2H(H2O)n+ + 2e-
– cathode: ½ O2 + 2H(H2O)n+ + 2e- H2O
• Catalysts
– anode: Pt/Vulcan carbon ~ 0.1 mg/cm2
– cathode: Pt/Vulcan carbon ~ 1 mg/cm2
– like other fuel cells, slow cathode kinetics, fast anode
• Features
– High power output due to rapid electrocatalysis rates
– Expensive materials
– Catalyst highly sensitive to impurities: CO
– Corrosive environment degradation, e.g. Pt coarsening
H2O recirculated
Polymer Electrolyte Membrane (PEM)
Solid Oxide Fuel Cell
• Electrolyte: yttria stabilized zirconia, YSZ, Zr0.92Y0.08O1.96
– true solid electrolyte
• Mobile species: O= [or oxygen vacancy]
• Half cell reactions
– anode: H2 + O= H2O + 2e-
– cathode: ½ O2 + 2e- O=
• Catalysts
– anode: Ni + YSZ
– cathode: (La,Sr)MnO3-
– like other fuel cells, slow cathode kinetics, fast anode
• Features
– Relatively high power output
– Expensive manufacturing, auxiliary component materials
– In principle, hydrocarbon fuels can be directly oxidized
– Under steady conditions, little degradation
Solid Oxide
Advantages
Some of the advantages of fuel cells are:• It is a direct conversion process and does not
involve a thermal process, so it has high operating efficiency. Present day fuel cell efficiency is 38% and is expected to reach 60%.
• The unit is lighter, smaller and needs less maintanence.
• Fuel power plants may further cut generation costs by reducing transmission losses.
• Little pollution, little noise so that it can be readily acceptable in resident areas.
Benefits of Using Fuel Cells
• They produce much small quantities of greenhouse gases that contribute to global warming.
• None of the air pollutants that create smog and cause health problems.
• If pure hydrogen is used as a fuel, ONLY heat and water are emitted.
Drawbacks
The drawbacks are: Low voltage High initial cost Low service life
Applications
Fuel Cell Generator
Fuel Cell Bus
Power Generation/ConversionFuel Cell Car
Hydrogen as a future energy source
Reasons for change
Environment Energy shortages Energy security
Reduction in greenhouse gases (CO2, NOx, SOx)
Eco friendly use of waste products
Desire to use renewable energy
Desire to meet emissions goals (eg: Kyoto)
Peak oil running out Hydrocarbon gas supplies a long
way from point of use Emergence of rapidly developing
economies greatly increasing World’s energy requirement
A long term energy solution
Minimising reliance on Imported energy
Changing political climate increases dependence on unstable regimes
Hydrogen can be produced from multiple sources
EnvironmentEnergy
shortage
Energy security
Energy Efficiency
• Maximum 80% efficient for conversion to H2 from other fuels.• Liquefying H2 uses up to 1/3 rd of it’s energy value!• Liquid storage losses can be 2-3% per day• Compression requires significant energy input input
It’s not energy efficient!
Environmental issues
• Steam Methane reforming produces more CO2
than current Hydrocarbon fuels for vehicles.• Electrolysis can be environmentally friendly
depending on how the electricity is produced.
It may not be Environmentally friendly !
So why Hydrogen?
• It will never run out – unlike Oil and Gas.• It can be produced in several ways from different
sources.• It provides energy security - any country can make
their own.• It can be used in either Fuel Cells (FC’s) or Internal
Combustion Engines (ICE’s)• The world wants an environmentally friendly fuel –
Hydrogen has the potential.• At some point, Hydrogen will be cheaper than
Hydrocarbons.• Clean at point of use
Hydrogen as a future energy source
• The use of energy may lead to climate changes. It is thus necessary to make the transition to cleaner and environmentally favourable energy carriers.
• Hydrogen has the best potential of becoming the fuel of the future. Hydrogen can be produced from sustainable, renewable sources and may contribute to meet the growth in world energy demand.
• Hydrogen is an energy carrier for the future. It is a clean fuel that can be used in places where it is hard to use electricity. Sending electricity a long way costs four times as much as shipping hydrogen by pipeline.
Hydrogen as a future energy source
• Hydrogen is a carbon-free energy carrier. When used in fuel cells, there are no harmful emissions.
• The current production of hydrogen is 500 billion m3/year,equivalent to 3.3 million barrels of oil per day. This again is equivalent to 10% of the energy currently used in transportation.
• Presently, hydrogen production represents only about 1 percent of worldwide oil production. The only place it has been used for fuel in significant quantity is the NASA space shuttle.
as a component of water, a resource available in large quantities
environmentally compatible as part of the biological life cycle
its oxidation creates pure water
easily transported and stored in compressed gas form or as a supercooled liquid
releases chemically stored energy in the form of heat, or in the form of electricity and heat in fuel cells
high energy content = suitable as fuel for cars
H2 as the energy source of tomorrow A storage medium for heat and electricity:
• hydrogen = ideal energy source to bridge the time and distance gaps between supply and demand:
H2 as the energy source of tomorrow
H2 as the energy source of tomorrow
On the way to our energy source of the future
On the way to our energy source of the future
Advantages of Sustainable Energy: fossil fuel resources no longer burnt
cyclical system: hydrogen as well as the energy required to generate it are derived from
renewable sources
combustion of hydrogen emits no greenhouse gases
local power supply in the home and cars
• The following hurdles may be overcome if hydrogen is to be a viable source of energy in the future:
The long-term nature of the transition may be recognized and a strategy developed now.
Durable and affordable fuel cells must be developed. On-board storage and safety issues must be resolved for
hydrogen – powered cars. Hydrogen has to be produced cheaply and in such a way
that doesn’t use more than it is produced.
Energy Conservation and Energy Management
Conservation is the reduction of usage.
Management is the judicious and effective use of utilities to maximize profits (minimize costs) and enhance competitive positions.
Energy Management vs Energy Conservation
EM is strikingly similar to FINANCIAL management:
• Identify goals;• Select the investments needed to reach the goals;• Establish a blueprint & strategy for goal attainment;• Start early, if only with small efforts; • Maintain regular contributions over time;• Keep track of earnings; and • Defeat risk through reinvestment and diversification of
earnings.
Energy and Financial Management
Initial Effort (First two years)
• 5-15% cost savings
• Little or no capital expenditure
Long-Term Effort
• 25% or higher cost savings
• Requires management commitment
• A never ending process
Energy Management Benefits
• Focus on COST not USAGE• Pareto Principle
– 20% of loads account for 80% of costs– Identify these 20% loads
• Control and meter these loads• Develop a “Cost Center” mentality
– Don’t treat utilities as overhead
Focusing Energy Management
•Designate an Energy Management Coordinator•Establish the Energy Management Team•Evaluate cost saving opportunities•Prioritize implementation•Implement•Evaluate success (e.g. benchmarking) and promote
Starting Your Energy Action Plan
• A single person
• Dynamic
• Goal oriented
• Good manager
• Wears other hats
Energy Management Coordinator
• Architect of the “Energy Action Plan”
• Provide effective energy reporting and analysis (energy accounting)
• Secure management commitment
• Establish “cost center” mentality
• Establish energy cost/usage standards
• Provide EM training
• Set EM objectives (defined goals)
GOALS OF THE EMC
• Reduce electric cost per unit of production by 10% the first year and 5% in the second
• Within 2 years all tenants will be separately metered
• Facility will have a contingency plan for gas curtailment by end of first year
• All boilers will be examined for waste heat recovery potential the first year
EXAMPLE ENERGY MANGEMENT GOALS
Energy Management Coordinator
Technical Support
Steering Group
ENERGY MANAGEMENT TEAM
Energy Management
Which factors does Energy Management deal with?
•People•Building•Energy type used•Installed equipment•External factors•Legislation – ‘One will have to comply’
Energy Conservation
Energy Conservation• In economic terms, energy is termed as a demand- derived
good.That is, energy is an intermediate good whose demand depends on the demand of the final (end-use) goods and services it produces.
• Energy conservation can be defined as the substitution of energy with capital labour or material and time.
• Energy conservation can also be defined as the substitution of this generation’s energy with that of future generations, known as “intertemporal substitution” (substitution of this generation energy with that of future generations).
• Energy conservation invokes avoiding wastage of energy and adopting methods to save energy without affecting the productivity and comforts of machine / labour.
The two points to be considered before demanding more
conservation efforts are:• Whether the depletion of the given resource can be offset
by new exploration and findings. That is, is the resource really limited, and hard to replace in a short time.
• The intertemporal welfare of consuming this type of energy. That is, is the marginal utility of consuming this energy in this generation larger than the utility of consuming it in the next generation.
Principles of Energy Conservation
The two principles governing energy conservation are• Maximum thermodynamic efficiency.• Maximum cost-effectiveness in energy use.
We can maximize this efficiency by the following conservation measures
• Using condensers to recapture the heat discharged as many times as possible
• Reducing heat loss with better heat exchangers
Maximum cost-effectiveness in energy use is achieved if the production factor or intertemporal substitution is made to maximize energy efficiency at the least cost. From this, maximum cost-effectiveness in energy use is determined by two cost components:
• Conservation costs (Costs for implementing energy conservation efforts in order to save energy)
• Energy costs (Unit energy cost will decline as more conservation measures are implemented to reduce energy use)
• Energy consumption in India is low, though efficiency of use is reasonable
– Per capita energy consumption is 530 kgoe; world average is 1770
– Energy intensity of Indian economy was 0.18 kgoe/$-GDP(PPP) in 2004; compared to 0.14 in Japan and 0.19 in the EU
• Energy demand is increasing due to rising incomes, accelerated industrialization, urbanization and population growth
– 2003-04 : 572 Mtoe
– 2016-17 : 842-916 Mtoe
– 2026-27 : 1406-1561 Mtoe
• Meeting the increasing demand only through increases in supply may lead to:
– Reduced energy security due to volatility in availability and prices of imported fuels
– Adverse environmental impacts
– Strain on balance of payments
• Energy conservation and energy-efficiency are an essential part of national energy strategy
Energy Use in India
IMPORTANCE OF ENERGY CONSERVATION
• Energy efficiency/conservation measures can reduce peak and average demand.
.• One unit saved avoids 2.5 to 3 times of fresh capacity. • Also avoids investment in fuel, mining, transportation etc.
• Keeping the above factors in view and also to provide a policy guidance, Government of India enacted the Energy Conservation Act,2001
Application of waste heat for energy conservation
Case study 1 : Distilled water from Engine exhaust heat
• CHP delivers electrical and thermal energy in such a way that much more of the energy content of the input fuel is used - by utilizing waste heat.
• Diesel engine operates with a thermal efficiency of 40%. So waste heat is 60% of the available heat.
For example, diesel car having the Air, Fuel ratio of 1: 15
• Mass of Exhaust gas leaving from the engine = 16 kg/kg of fuel
• Engine exhaust gas temperature = 600 C• Specific heat of flue gas = 0.25 kcal / kg K
• Quantity of heat available if we reduce the flue gas temperature 600 to 300 C
Q = m Cp (T2-T1)
= 1200 kcal• Quantity of heat required making the water into steam • (Sensible heat + Latent heat) = 594.5 kcal / kg We are able to get 2 lt of distilled water for every
liter of Diesel
Application of Renewable energy systems for energy conservation
Case study 2 : Solar water heater for fuel savings 1% fuel can be saved for every 6ºC rise in temperature
of boiler feed water. 100 LPD (Litres per day) solar water heater can rise the
temperature from 32ºC to 62ºC (ΔT = 30°C), costs around Rs 18,000.
5% fuel saving can be achieved with the help of solar water heater.
100 MW thermal power plant requires 60 tons/hr of coal 5% of fuel saving is 3 tons/hr so Rs 9000/hr is saved.
• 8000 working hours in a year, saves Rs 7,20,00,000.• 100 MW thermal power plant requires 10 tons/hr (2,40,000
lt/day) of feed water.• So 2400 Nos of 100 LPD solar water heater is needed for 100
MW thermal power plant which can rise the boiler feed water to 62°C.
• Initial investment for 2400 nos of solar water heater is Rs.4,32,00,000.
• Payout time is less than one year. (4,32,00,000 / 7,20,00,000).• Life of the solar water heater is 10 yrs.• The energy conservation method could be thought of wherever
there is a demand for process heat.
Optimum Utilization of Heat and Power
Waste Heat Recovery
• Waste heat is defined as the heat rejected from a process which is sufficiently at a higher temperature than the ambient temperature.
• Waste heat could include exhaust steam from process industries, heat from power plants and heat generated from various other streams such as agricultural crops, food process waste, waste tyres etc.
• Approximately two-thirds of industrial energy is used in process steam and heat, and this is in the form of thermal energy, rather than in the form of power. Consequently, the opportunities for waste heat recovery are plentiful.
• However in establishing the opportunities, process energy requirements and waste streams technology of recovery need to be evaluated. Their costs and energy savings are vital to the determination of the economic viability of waste heat recovery.
• Three temperature ranges are used to classify waste heat.
The high temperature range - above 1200°F The medium temperature range - between 450°F and
1200°F The low temperature range - below 450°F
Sources of waste heat• High temperature waste heat - Aluminium refining furnace, cement kiln, solid waste incinerators• Medium temperature waste heat - Steam boiler exhausts, gas turbine exhausts, heating furnaces• Low temperature waste heat - Cooling water from internal combustion engines, process steam condensateThere are two basic ways to recover heat from the sources:o Using heat exchangers to transfer heat in one fluid stream to
another. e.g. from flue gas to feed water (economizer) or combustion air (air
preheater).o Waste heat boilers to produce steam.
Waste Heat Recovery
Combined Heat and Power• Scheme which combines electrical power generation with
utilization of heat for space heating and / or specific industrial process.
• The maximum efficiency of the thermal power plant is 30-40%.• The application of the Carnot principle to any heat engine
cycle shows that however efficient the cycle may be, the maximum efficiency is given by
carnot = 1-(T2/T1) T1 = Maximum temperature available (e.g. the metallurgical limit) T2 = Lowest temperature available• In a steam power plant, if the heat rejected in the condenser
were utilized the overall efficiency would be increased to about 75-80%.
• The existing power plants, scope for use the heat rejected from the condenser is limited-the reason.
– The temperature of heat rejection is low (Lower grade Heat)
– Power stations are far away from the recipients of thermal energy
Benefits of CHP
• Local generation of electricity• Improvement in national energy efficiency and
preservation of non-renewable energy sources• Cogeneration• Employment opportunities
Energy Management and Energy Audit
Energy Management & Audit
Energy Management can be divided into 3 process • Analysis, Action & Monitoring• Energy Audit is a part of the Action step. An
energy audit is the collection and analysis of data on present energy use, the choice of energy management objectives and of specific measures to meet these objectives and the process used to monitor progress towards these objectives
• To convert data into information
ENERGY MANAGEMENT
....INVOLVES A COMBINATION OF
- MANAGERIAL
&
- TECHNICAL/TECHNOLOGICAL- SKILLS/KNOWLEDGE
GLOBAL/NATIONAL BENEFITS
• immediate results• lower power plant capacity• reduced load shedding• reduced energy imports• lower foreign exchange needs• use of local equipment• job creation• lower inflation• reduced emissions/pollution• conservation of scarce/limited resources
GLOBAL ISSUES
• ENERGY USE
• ENVIRONMENTAL DAMAGE
• NUCLEAR SAFETY/HEALTH
• SO2, NO - ACID RAIN, OZONE DEPLETION
• CO2 - GREENHOUSE EFFECT.
BARRIERS/OBSTACLES TO MANAGEMENT OF ENERGY
• Artificially low energy prices.• Little energy consciousness.• Higher priority to “more important” issues (eg., keep plant
running).• Automation seen as more important than energy cost
management, in plant modernisation of plant.• Lack of energy management expertise• Lack of knowledge of own energy consumption
patterns/costs/ potential for saving
• Old, high-energy plant.• Lack of capital.• Other investment priorities.• Local energy infrastructure may not encourage energy
saving.• Apathy on the part of managers and staff.
• Lack of awareness of energy engineers, technological possibilities, and economics.
BARRIERS/OBSTACLES TO MANAGEMENT OF ENERGY
ENERGY MANAGEMENTThe objective of Energy Management is to achieve and maintain
optimum energy procurement and utilisation, throughout the
organisation:
- To minimise energy costs/waste...
- Without affecting production.
- To minimise environmental effects.
ENERGY MANAGEMENT INVOLVESFOUR MANAGERIAL FUNCTIONS
... PLANNING
... LEADING
... ORGANISING
... CONTROLLING
THE TOTAL ENERGY MANAGEMENT PROCESS
Awareness of Potential Savings
Top Management Commitment
Preliminary Energy Audit
Detailed Energy Audit
Implement No-Cost/Low-Cost Measures
Training Monitor
Implement Higher-Cost
Measures
Feasibility Studies-Capital Intensive Projects
Conducting An Energy Audit
OUTLINE
Initiating an Energy Management Program Goals of the Energy Audit Energy Bills Steps in the On-Site Energy Audit Degree Days, Layout, Operating Hours Equipment List Systems to Consider Energy Audit Report
Starting an Energy Management Program
Conduct an energy audit
An energy audit (or energy survey) is:
A study of how energy is used in a facility and an analysis of what alternatives could be used to reduce energy costs
improve profits
Goals of the Energy Audit are to:
Clearly identify types and costs of energy useUnderstand how that energy is being used – and
possibly wastedIdentify and analyze more cost-effective ways of
using energy- improved operational techniques
- new equipment
Perform an economic analysis on those alternatives and determine which are cost-effective for your business or industry
Steps in the On-site Energy Audit
1. Identify layout and operating schedule for facility.
Make a plan or sketch of the building(s) which shows building size, room sizes, window areas, and wall and roof composition and insulation (offices, prod, maint,…)
2. Compile an equipment inventory.
List all energy consuming equipment, with hours of use each year and energy ratings or efficiencies.
3. Determine the pattern of building use to show annual needs for heating, cooling, & lighting.
4. Conduct a room-by room lighting inventory
- light fixtures
- lamp types, sizes and numbers
- levels of illumination
- uses of task lighting
Steps in the On-site Energy Audit
Responsibilities and Duties of Energy Auditor
• Carry out a detailed energy audit • Quantify energy consumption and establish base line energy
information • Construct energy and material balance • Perform efficiency evaluation of energy & utility systems • Compare energy norms with existing energy consumption
levels • Identify and prioritization of energy saving measures • Analyse technical and financial feasibility of energy saving
measures • Recommend energy efficient technologies and alternate
energy sources • Report writing, presentation and follow up for implementation
Responsibilities and Duties of Energy Manager
• Establish an energy conservation cell & prepare an annual activity plan
• Develop and manage training programme for energy efficiency at operating levels
• Develop integrated system of energy efficiency and environmental improvement
• Initiate activities to improve monitoring and process control to reduce energy costs
• Co-ordinate implementation of energy audit/efficiency improvement projects through external agencies
• Establish / participate in information exchange with other energy managers of the same sector through association
• Provide information to BEE and Designated Agency of the respective States as demanded in the Act
Industrial and Building Energy Management
Industrial and Building Energy Management
• Optimum uses of thermal, Electrical energy in industrial & building activities
• In industrial activities, the following is the key elements for energy management
• The efficiency improvement• Waste heat recovery potential • Optimum use of steam• Cogeneration• Optimum thickness of insulation • Optimum of natural lighting & ventilation
• In Building energy management, the key elements are– Lighting– Heating & Cooling– Construction
Some important points in Building Energy Management• Switch off the fans, light and TV whenever they are not
in use • Clean the tube light for every fortnight to get a good level
of illumination • Clean the dust settled over the fan blade to get a
designed amount of air• Use CFL (Compact Fluorescent Lamp) – lead to energy
conservation• CFL lamps can be used where maximum duration of
lighting is essential • For Street lightings, CFL gives more benefit than our
incandescent lights
• If you use Electronic choke instead of regular choke in Tube light, you can save 16% of Electricity
• Use electronic regulator instead of ordinary regulator for fans
• Keep your refrigerator 7” away from the wall to save 7% of electricity
• Decide the level of cooling you required for the operation of the refrigerator to save power (Low, Medium or High Cool)
• Choose the required size of the refrigerator in order to avoid the power for cooling the empty space of the refrigerator
Bulb (Watt)CFL lamp
(Watt)Lumens Amount (Rs)
40 8 400 215
75 14 900 235
100 18 200 400
Comparison in cost saving of CFL lamp – basis: 8 hours operation /day
40 Watt Lamp 8 Watt CFL Lamp
40 W 8 hours 30 days = 9.6 Units 8 W 8 hours 30 days = 1.92 Units
For 1 year = 115.2 Units For 1 year = 23 Units
Cost = 115.2 Rs. 2.20 = Rs. 253.44 Cost = 23.0 Rs. 2.20 = Rs. 50.60
Cost saving for one year=Rs 202.84
Payout Time = l year
Energy Management in Lighting
Lighting• When a metallic material becomes hot, it emits radiation.
This happens in an incandescent bulb when it is switched on. The thin filament is heated to such a high temperature by the electrical energy fed into it that it begins to glow and emit radiation. Some of the radiation is invisible (heat radiation) and some visible (light)
Sources of light:• Light source can be classified as• Natural light – Varies constantly with changing
metrological conditions, time of the day, seasons and specific location on earth– Sunlight – light received directly from the sun– Skylight – scattered light received from other
luminous parts of the sky
Artificial light • Flame based – they evolved from firelight, oil
lamps, modern kerosene, gas lamps, candles etc.,
• Electrical light – incandescent and discharge lamps
Light and Energy
– A source of light needs energy, either electrical or heat
– Input to lighting – for the flame based systems it is necessary to know the net heating value and rate of consumption of the fuels used or for electrical lighting systems, the power ratings of the lamps
– Output energy – it is also possible to measure the quantity of energy that is contained in the output of lighting system, i.e., in the light
– It is possible to measure how the emitted energy of a 100W incandescent lamp is distributed over the radiation spectrum
– These measurements take the spectral sensitivity of the eye in to account
- Total light energy emitted by a 100W bulb is 1700 lumen, which is only a fraction of the 10W energy in the visible range. This quantity is called by definition the luminous flux
Energy
UV Visible Infrared
0 0.4 0.8 1 2 3 4
Wave length (micrometers)
Photometric Quantities
Illuminance - unit Lux (lx)• The luminous flux falling on unit area of a surface and is
expressed in lux• Office desk - 300/500 lx• Corridor - 100/500 lx• Classroom - 300 lx• Restroom - 150 lx• Living room - 50/300 lx• Bedroom - 50 lxLuminous intensity – unit candela (cd)The luminous flux per unit of solid angle in a given direction
Luminous flux – unit lumen (lm)• Total amount of light emitted by a source or received by a
surface• Candle – 5 lm• 100W incandescent lamp – 1700 lm• 60W fluorescent lamp – 3600 lm
Luminance – unit (cd/m2)• Express how bright the source appears
Luminous efficacy – unit (lm/W)• It is the energy to light conversion• In incandescent bulb, it gives 17 lm/W (i.e., 1700 lm/100W)
Average illuminance on an area:• It is expressed as,E = lu/swhere, E – Average illuminance (lx)
lu – Average luminous flux (lm) s – Surface area (m2)Illuminance at a point:• The illuminance at a point can be
calculated easily when the size of the source is small compared with its distance from the surface
E point = (Li / d2) cosine b
where• E point – illuminance at a point (lx)• Li – luminous intensity (cd)• d – distance between the source of light and the point
(m) • b – angle between the beam and a line perpendicular to
plane of the surface
b
Spot light
d
Epoint
Colour and Colorimetry
• A distinction is made between the colour temperature of a light source when you look at the light itself and the colour rendering that it gives to surface when it shines onto them
• The colour-rendering index expresses how a light source compares with natural light or daylight in its ability to make objects appear to their natural colours. Put more precisely, it is a measure of the degree to which the colour of surfaces illuminated by a given light source confirm to those of the same surfaces under a reference light. Some form of daylight is taken as the reference source
• Perfect agreement between the source being judged and the reference source is given a value of 100
CIE colour rendering % Typical applications Example of lamps
90 (Good) Accurate colour matching Incandescent lamps
80-90 (Good) Accurate colour judgment or good colour rendering for reasons of appearance
Fluorescent tubes (with triphosphor fluorescent coating)
60-80 (Medium) Moderate colour rendering
Standard Fluorescent tubes
40-60 (Medium) Little significant colour rendering, but marked distortions of colours unacceptable
High-Pressure mercury lamps
20-40(Poor) Colour rendering not important and colour distortion acceptable
Low-Pressure sodium lamps.
Illuminance for different purposes
• The following table gives the scale of illuminance recommended by CIE for use in working interiors:
• These standards illuminances are based on consideration of the performance of the respective tasks, the comfort of people doing the tasks, and the time, which the space is occupied
Comparison of lighting systemsType of
light sourceEnergy source
Rate of consumption
Total power
Luminous flux
Luminous efficacy
Color rendering
Equivalent number of lamps(*)
W lm lm/W
Candle Wax 5.50 g/h 55 1 0.02 Good 75
7.20 g/h 72 16 0.22
Kerosene lantern
Kerosene 0.02 l/h 200 10 0.05 Good 12
0.05 l/h 488 100 0.25
Pressure lamp
Kerosene 0.06 l/h 563 220 0.39 Poor 1
0.08 l/h 813 1300 1.60
Gas lamp LPG 28 l/h 350 330 0.94 Poor 1
34 l/h 425 1000 2.35
Biogas lamp Biogas 0.10 m3/h 639 330 0.48 Poor 1
0.20 m3/h 1385 1300 0.94
Examples of electrical lamps
Incandescent lamp
Electrical 100W 100 1200 12 Good 1
Halogen lamp Electrical 25W 25 500 20 Good 2
Fluorescent tube
Electrical 13W 13 585 45 Good 2
(*) – The equivalent number of lamps is the number of lamps required to produce the same luminous flux as the reference of 100W incandescent electrical bulb (i.e. 1200 lm)
