Prof. R. Shanthini 10 March 2012 Module 10 Energy Management Energy management basics Energy audit Demand-side management Life-cycle assessment Exergy

Prof. R. Shanthini 10 March 2012

Module 10

Energy Management

Energy management basics

Energy audit

Demand-side management

Life-cycle assessment

Exergy analysis

Carbon and ecological footprints

Clean development mechanism


Remarks by Bob Dudley, Group Chief Executive, BP at launch of BP Energy Outlook 2030, London, 18 January, 2012:

I think most people would agree on the objectives.

- We want the world to have enough energy for growth and development (affordability).

- We want that energy to come from sources we can rely on (security).

- We want it to be produced and consumed in a way that is safe and compatible with the health of the environment (sustainability) .

But we need to be clear about what is possible and what is not.

http://www.bp.com/genericarticle.do?categoryId=98&contentId=7073056



Five realities:

- continue to anticipate strong growth in demand for energy

- fossil fuels continue to provide around 80% of the world’s energy in 2030

- oil will remain the dominant transport fuel (87% of transport fuel in 2030 will still be petroleum-based)

- industry needs to go to new frontiers to find oil - and indeed alternatives.

- significant rise in greenhouse gas emissions (in the most likely case)



Energy Production (million tonnes oil equivalent):

http://www.bp.com/energyoutlook2030

liquidsliquids

Natural GasNatural Gas

Coal Coal

Nuclear Nuclear

Hydro Hydro

Renewables biofuels Renewables biofuels

London, 18 January, 2012

Prof. R. Shanthini 10 March 2012 http://www.bp.com/energyoutlook2030


Australia Austria

Belgium Canada

Chile Czech Republic

Denmark Estonia

Finland France

Germany Greece

Hungary Iceland

Ireland Israel

Italy Japan

Korea Luxembourg

Mexico Netherlands

New Zealand Norway

Poland Portugal

Slovak Republic Slovenia

Spain Sweden

Switzerland Turkey

United Kingdom United States

Organisation for Economic Co-operation and Development

http://www.oecd.org/country/0,3731,en_33873108_33873229_1_1_1_1_1,00.html

































First opportunity: Efficiency

Saving energy through greater efficiency addresses several issues at once.

It helps with affordability (because less energy is needed).

It helps with security (because it reduces dependence on imports).

It helps with sustainability (because it reduces emissions).

Efficiency can be achieved through improving processes or reducing waste, but it is also frequently enabled by technology.




Second opportunity: Technology

Example: Supply of gas has been accelerated as a result of technologies that unlock shale gas and tight gas.

In the transport sector, we believe the efficiency of the internal combustion engine is likely to double over the next 20 years. And that will save roughly a Saudi Arabia’s worth of production.

By 2030, we expect hybrids to account for most car sales and roughly 30% of all vehicles on the road.

Technological innovation is driven by many factors – economic, scientific, political and personal – but the primary driver is frequently competition.




Third opportunity: Competition

Last year average oil prices reached an all-time high. However, high prices stimulate competition, which leads to innovation, as we strive to find lower cost solutions.




Fourth opportunity: Natural gas

Natural gas typically generates fewer than half the emissions of coal when burned for power.




Fifth opportunity: Biofuels

We have an optimistic view on the future of biofuels - but production needs to be scaled up.

The world needs to focus on biofuels that do not compete with the food chain and are produced in a sustainable way.

The greatest promise is offered by next generation biofuels such as those derived from cellulosic plants.




So this study highlights some clear opportunities for accelerating progress towards secure and sustainable energy.

The first three are linked:

competition helps to drive technology, which in turn helps to drive efficiency,

and the second two are examples of this process at work – the growth of natural gas and biofuels.



Energy Management aims to lower the cost by

- eliminating unnecessary energy use

- improving the efficiency of needed energy use

- buying energy at lower net prices

- adjusting operations to allow purchasing energy at lower prices

www.EnergyBooks.com


What is Energy Management?

http://africa-toolkit.reeep.org/modules/Module14.pdf

Energy management is the process of

monitoring,

controlling and

conserving (saving) energy.


Why should energy be conserved (or saved)?

- To reduce our dependence on fossil fuels that are becoming increasingly limited in supply (peak oil phenomenon)

- To reduce the damage that we are doing to our plant (global warming, and other energy related pollution)

- To ensure a sustainable energy future

- To be able to continue to afford energy

- To reduce the risk of energy dependence

http://www.energylens.com/articles/energy-management


The four steps of effective energy management

1) Identify ALL your opportunities (by carrying out an

energy audit using competent people)

2) Prioritize your actions rationally (by considering all

the criteria that matter, not just the economic criteria)

3) Accomplish your activities successfully.

4) Maintain your activities endlessly (failure is the largest cost of energy conservation)

www.EnergyBooks.com


Step 1: Identify all your opportunities

- Carry out an “energy audit” to find all your opportunities.

- The energy auditor requires scientific and engineering education, broad practical experience, and solid judgement.

- The energy auditor needs a thorough understanding of ALL opportunities, not just a few.

- A good “energy audit” takes time and costs money.

- Even today, competent energy audits are rare.

- Lack of competent energy audits is the greatest deficiency of present energy management, which results in continued high energy costs, and waste of money on ineffective action.

- The energy audit is the foundation on which the entire energy management program rests. A deficient energy audit WILL cause a deficient energy management program

www.EnergyBooks.com


Step 2: Prioritize your activities rationally

- The sequence of activities is a major factor in the economic benefit of energy management program.

- Consider all the criteria that matter, not just the economic criteria. Cost, by itself, is almost never a significant selection factor. Because, IF the measure works as expected, it provides a higher rate of return than most other investments. So, you can borrow the money, if necessary.

- Calculate with realistic numbers.

- Limit consideration to measures of proven reliability.

- Consider the ability of your staff to accomplish and maintain each measure.

www.EnergyBooks.com


- Each cost saving activity is an independent project that requires its own knowledge, equipment, and people.

- The key to success is doing the homework before initiating each activity.

www.EnergyBooks.com

Step 3: Accomplish your activities successfully

Prof. R. Shanthini 10 March 2012 www.EnergyBooks.com

Step 4: Maintain your activities endlessly

- Almost nothing continues to operate successfully by itself.

- Each energy management activity requires continuing support.

- Integrate the maintenance of each activity seamlessly into your overall operations.


The largest cost of energy conservation is FAILURE.

If an activity does not work, it will not pay back.

Keep tuning the program. There is always room for improvement.

Energy management NEVER ENDS.

www.EnergyBooks.com


Selected topics in Energy Management:

Energy audit



Exergy analysis




Energy audit


- What type of energy is being used?

- How much energy is used?

- What is the consumption pattern?

- How much does it cost?

- What are the areas of priority?

Try to answer the above questions in an energy audit.


Energy Audit

at a Processing Plant

(example)


Methodology of Energy Audit

Pre-audit presentation.

Collection of data / information.

Measurements and monitoring with instruments.

Computation and in-depth analysis.

Post-audit presentation to discuss the Energy Conservation Opportunities identified by the audit team.


Scope of Energy Audit

ELECTRICAL

Electrical Distribution Network and Transformers

Motive Loads

Illumination System

Compressed Air System

Cooling Tower

Refrigeration System

THERMAL

Boilers

Steam Traps

Steam Distribution

Insulation


Electrical System Network & Transformers

• This would include detailed study of all the transformer operations of various ratings / capacities, their operational pattern, loading, no load losses, power factor measurement on the main power distribution boards and scope for improvement if any.

• The study would also cover possible improvements in energy metering systems for better control and monitoring.


Motive Load

• Study of above 10 HP motors in terms of measurement of voltage (V), current (I), power (kW) and power factor in a complete cycle.

• Suggestion of measures for energy saving like reduction in size of motors or installation of energy saving device in the existing motors.

• Study of mechanical power transmission systems (pumps, fans, blower, etc.) to evolve suitable recommendations wherever feasible for energy efficiency improvements.


Illumination System

• Study of the illumination system, LUX level in various areas, area lighting etc.

• And, suggest measures for improvements and energy conservation opportunity wherever feasible.


Compressed Air System

• The audit would involve analysis of various parameters like free air delivery (FAD) capacity of the air compressors, leakages in the system, feasibility of pressure optimisation etc. wherever feasible /appropriate.


Cooling Towers

• This would include detailed study of the operational performance of the cooling towers through measurements of temperature differential, air/ water flow rate, to enable evaluate specific performance parameters like approach, efficiency etc.


Refrigeration System

• The audit would involve analysis of various parameters like co-efficient of performance (COP), tonnage delivered, effectiveness of the ducting and allied systems, measurement of specific energy consumption, study of refrigerant compressors, chilling units etc.

• Further, various measures would be suggested to improve its performance.


Boiler Operations

• Study of steam generating systems, their combustion performance, heat balance, air to fuel ratios, blow down losses etc.

• Suggest suitable recommendations for improvements.


Steam Distribution Network (including Traps & Insulation)

• Study of steam distribution network including layout of the steam pipelines, estimation of losses etc. to suggest suitable recommendations for improvements.

• The steam traps would be checked for its proper functioning.

• The study would also include evaluation of the radiation losses, steam leakages and insulation effectiveness.


Diesel Generator (DG) Sets

• Study the operations of DG Sets to evaluate their average cost of power generation, specific energy generation and subsequently identify areas wherein energy savings could be achieved after analysing the operational practices etc. of the DG Sets.


Instruments Used

Flue Gas Analyser

Power Analyser, Tachometer

Ultrasonic Flow Meter

Trap Man (For Steam Trap Survey)

Raytech Gun & Digital Thermometer (Non-contact and Contact type both)

Anemometer, pH/TDS/Conductivity meter

LUX Meter, Digital Manometer


Boilers

Observations:1. Condensate recovery is not being done.2. Feed water temperature presently is 50C.

Recommendations:1. Recover condensate to raise feed water temperature

to upto 85C2. Install de-aerator head on feed water tank and

recover condensate.3. Install steam operated condensate recovery pump

Savings Estimated / year Investment Payback Period

Rs 2,834,000 Rs 2,500,000 11 Months


Refrigeration SystemObservations:1. Pumps connected to silos are of higher capacity of 15 kW.2. Cooling water pumps of 45 kW are under loaded.3. Glycol pumps of 15 kW are under loaded. 4. Water cooled condensers have poor performance

Recommendations:1. Replace 15 kW pumps connected to silos with 11 kW pumps.2. Install variable frequency drive (VFD) for cooling water pumps

to save 40 kW. 3. Install VFD for glycol pumps to save 8 kW.4. Install air cooled condensers to save 6 kW.


Rs 572,000 Rs 480,000 9 Months


Illumination

Observations:1. High pressure mercury vapour (HPMV) lamps are used

for street lighting.2. 36 Watt tubelights with copper chokes are used.

Recommendations:1. Replace HPMV lamps by High pressure sodium vapour

(HPSV) lamps2. Replace 36 Watt tubelights with T-5 28 Watt with

electronic choke in a phased manner.


Rs 344,000 Rs 400,000 16 Months


Steam Traps & Condensate

Observations:

1. All steam traps are working properly.

2. But, there is no condensate recovery from steam traps.

Recommendations:

1. Recover the condensate and use it as boiler feed water and thereby increase the boiler feed water temperature.


Motive Load

Observations:

1. Diffuser & disposable pumps motors are loaded only 27% & 36% respectively.

2. Boiler feed pump motors are overloaded to 125%.

Recommendations:

1. Running the diffuser pump and disposable pump motors in STAR mode.

2. Checking the condition of boiler feed pumps & repairing the same.


Rs 110,000 Nominal Immediate


Air Compressors

Observations:

1. The loading and unloading pressure of air compressors is 7.5 kg/cm2 and 8.5 kg/cm2 which is high.

2. The air leakages are 37%.

Recommendations:

1. Reducing the loading and unloading pressure to 6 kg/cm2 and 7 kg/cm2 as the working pressure is 6 kg/cm2

2. Plugging the air leakage.


Rs 260,000 Nominal Immediate


Cooling Tower

Observations:1. CT fan is operating continuously without taking into

account the inlet and outlet temperature variation ( T)

Recommendations:1. Installation of Automatic Temperature Controller (ATC) on

the CT fan


Rs 40,000 Rs 15,000 4 Months


Types of audit strategy:

3-stage audit:

- Historical data collection

- Preliminary survey

- Detailed investigation and Report



4-stage audit:

- Preliminary survey

- Walk-through

- Operator’s input

- Report



5-stage audit:

- Study and evaluation

- Detailed real-time measurement

- Analysis

- Quantification

- Report



6-stage audit:

- Meet up with Facility Personnel

- Site walk-through

- Discuss with Facility Personnel

- Analyze historical data

- Short-term measurement

- Report



10-stage audit:

- Interview with key Facility Personnel

- Facility tour

- Document review

- Facility inspection

- Staff interviews

- Utility analysis

- Identify/Evaluate feasible ECMs

- Economic analysis

- Report

- Review



Energy audit



Exergy analysis




Demand-side Management (DSM)


DSM modifies or reduces energy demand by end-users.






DSM is mostly used to reduce peak electricity demand, which helps in reducing the number of blackouts and in delaying the construction of new power plants.

DSM is also used for changes that can be made to demands for all types of energy (used transport and industries, and so on).




Possible benefits of DSM can also include - reducing dependency on expensive imports of fuel, - reducing energy prices, and - reducing harmful emissions to the environment.




The main types of DSM activities may be classified in three categories:

Energy reduction programmes

Load management programmes

Load growth and conservation programmes




Energy reduction programmes—reducing demand through more efficient processes, buildings or equipment:

- Boilers- Steam systems- Lighting - Energy efficient motors (and drive systems) - Compressed air systems- Efficient lightings




Load management programmes—changing the load pattern and encouraging less demand at peak times and peak rates:

- Load levelling- Load control- Tariff incentives and penalties




Load growth and conservation programmes.



Energy audit


Life-cycle assessment (ISO 14000 series)

Exergy analysis





Energy audit


Life-cycle assessment (ISO 14000 series)

Exergy analysis




First law of thermodynamics states that energy is neither produced nor destroyed.

That is, the energy contained in all of the input streams to a process must be accounted for somewhere in the output streams from the same process or accumulated within the system in which the process is occurring.

An output stream could be a loss to the atmosphere or other heat sink.

Exergy Analysis:

Applied Thermal Engineering 24 (2004) 525–538


As a fundamental measure of the thermodynamic deviation of a considered system from its environment, exergy is equal to the maximum amount of work the system can perform when brought into thermodynamic equilibrium with its reference environment.

Unlike energy, exergy is not subject to a conservation law with the exception of ideal or reversible processes.

The exergy consumption during a process is proportional to the entropy created due to irreversibilities associated with the process.

Exergy Analysis:



The first law (energy) efficiency

= energy of the useful streams leaving the process

/ the energy of all input streams

Exergy Analysis:






The second law (exergy) efficiency

= exergy contained in the products of a process

/ the exergy in all input streams

Exergy Analysis:






The second law (exergy) efficiency

= exergy contained in the products of a process

/ the exergy in all input streams

Exergy is the quality of energy which is destroyed by the

irreversibilities in a real process.

Therefore, exergy efficiency < energy efficiency

Exergy Analysis:



Energy and exergy balances for an unsteady-flow process in a system during a finite time interval:

Exergy Analysis:




Since energy is conserved,

Energy input = Energy output + Energy accumulation

Exergy Analysis:






Since exergy (quality of energy) is consumed due to irreversibilities,

Exergy input = Exergy output + Exergy consumption + Exergy accumulation

Exergy Analysis:






Since exergy (quality of energy) is consumed due to irreversibilities,

Exergy input = Exergy output + Exergy consumption + Exergy accumulation

For any real process, exergy is destroyed or lost.

Exergy Analysis:



The total exergy of a system E is divided into four components:

physical exergy EPH

kinetic exergy EKN potential exergy EPT

chemical exergy ECH

E = EPH + EKN + EPT+ ECH

Exergy Analysis:

Energy Policy 39 (2011) 2475–2481


Process Energy (First Law) Exergy (Second Law) efficiency (%) efficiency (%)

Residential heater (fuel) 60 9

Domestic water heater (fuel) 40 2–3

High-pressure steam boiler 90 50

Tobacco dryer (fuel) 40 4

Coal gasification (high heat) 55 46

Petroleum refining 90 10

Steam-heated reboiler 100 40

Blast furnace 76 46

Exergy Analysis:



When high-temperature energy resources, such as fossil fuels are used for relatively low-temperature applications (residential heating and domestic hot water), exergy loss is large.

This will make exergy e ciencies much smaller than their ffirespective energy e ciencies. ffi

Therefore, it is important to note that high-temperature energy resources should be used for high-temperature applications.

Exergy Analysis:



Exergy analysis appears to be a potential tool in:

• addressing the impact of energy resource utilization on the environment,

• furthering the goal of more e cient energy resource utilization,ffi

• determining locations, types and true magnitudes of wastes and losses,

• revealing whether or not and how much it is possible to design more e cient energy systems by reducing the ine ciencies,ffi ffi

• providing a sustainable developments as a result of sustainable supply of energy resources, and

• distinguishing the high-quality and low-quality energy resources.

Exergy Analysis:



Exergy Efficiencies (%) of Railways in Turkey:

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

1985 1990 1995 2000 2005

Hard coal

Lignite

Oil

Electricity

Energy Policy 35 (2007) 1238–1244


Exergy Efficiencies (%) of Transport Sector in Turkey:

0

5

10

15

20

25

1985 1990 1995 2000 2005

Railways

Seaways (oil)

Airways (oil)

Highways (oil)

Energy Policy 35 (2007) 1238–1244


Overall Exergy Efficiency (%) of the Transport Sector in Turkey:

0

5

10

15

20

25

1985 1990 1995 2000 2005

Energy Policy 35 (2007) 1238–1244


Overall Exergy Efficiency (%) of the Transport Sector:

Energy Policy 35 (2007) 1238–1244

Country Year Efficiency

Norway 1985 16

Sweden 1980 10

1994 13

Italy 1990 10

Japan 1985 10

Turkey 1995 15

Brazil 1987 10

Canada 1986 23

Finland 1985 10

USA 1970 20


Overall Exergy Efficiency (%) of the Transport Sector:

Energy Policy 35 (2007) 1238–1244

Country Year Efficiency

Norway 1985 16

Sweden 1980 10

1994 13

Italy 1990 10

Japan 1985 10

Turkey 1995 15

Brazil 1987 10

Canada 1986 23

Finland 1985 10

USA 1970 20

Exergy Efficiency is 16% for the World in 1990

Exergy Efficiency is 15% for OECD in 1990


Exergy efficiency of solar collectors :Solar collector system Exergy efficiency

- glazed PV/T water collector 13.30%- coverless PV/T water collector 11–12.87% - unglazed PV/T air collector 10.75% - (glass-to-glass) PV/T air collector 10.45% - glazed PV/T water collector 8–13% - PV array 3–9% - unglazed PV/T air collector

integrated greenhouse withearth air heat exchanger 5.50%

- unglazed PV/T air collectorintegrated greenhouse 4%

- double glazed flat-platewater collector 3.90%

- double glazed air heater 2%

Energy and Buildings 2010;42:2184–99


Overall exergy efficiency of different sectors in Greece in 2000 :

Energy Policy 39 (2011) 2475–2481

Transport 22%

Residential 34%

Industrial 51.6%

Documents

Prof. R. Shanthini 10 March 2012 Module 10 Energy Management Energy management basics Energy audit Demand-side management Life-cycle assessment Exergy