SUSTAINABLE ENERGY Unit 2.

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

Comparison of various energy sources
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 Priority Power Agricultural

Non-Renewable Energy Sources
Conventional Petroleum Natural Gas Coal Nuclear Unconventional (examples) Oil Shale Natural gas hydrates in marine sediment Non-renewable energy sources include fossil fuels and nuclear sources that are essentially finite in the earth’s crust. These represent the energy resource endowment for current and future generations. These resources can be classified further as conventional and unconventional. Unconventional resources are not currently exploited at significant levels generally because they can not be economically extracted and/or refined. Oil shale is source rock that has not yet released its oil. In the 1970’s it was thought to be the answer to US energy self-sufficiency. Oil shale is pulverized and heated to C (pyrolyzed, but the oil requires further upgrading before a refinery can use it as a feedstock. Natural gas hydrates in marine sediment are a mixture of methane and H2O frozen into solid crystalline state at water depths of approximately 500m. It is derived from the decay of organic matter trapped in the sediment. It has been estimated that this resource is as large as 2x all known fossil fuels.

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

Demand comparison of 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 based on calorific value (100% efficiency)
Fuel Wood (kg) Char Coal Kerosene Petrol Diesel Furnace Oil LPG Biogas m3 Electricity Unit 1 0.6 0.4 0.3 0.25 0.27 0.28 0.15 0.48 3.33 Charcoal 1.66 0.66 0.5 0.42 0.45 0.47 0.8 5.55 2.5 1.5 0.75 0.63 0.68 0.71 0.37 1.2 8.33 2 1.33 0.85 0.90 0.95 1.6 11.11 3.91 2.35 1.56 1.17 1.06 1.11 0.58 1.88 13.05 3.66 2.2 1.46 1.1 0.93 1.04 0.55 1.76 12.22 Furnace Oil 3.5 2.1 1.4 1.05 0.89 0.52 1.68 11.66 6.66 4 2.66 1.70 1.81 1.90 3.2 22.22 Biogas 2.08 1.25 0.83 0.67 0.53 0.56 0.59 0.31 6.94 0.18 0.12 0.09 0.07 0.081 0.085 0.04 0.14

Demand comparison based on calorific value (Actual efficiency)
Fuel Wood (kg) Char Coal Kerosene Petrol Diesel Furnace Oil LPG Biogas m3 Electricity Unit (12%) 1 0.36 0.16 0.07 0.06 0.03 0.11 0.44 Charcoal (20%) 2.77 0.2 0.17 0.18 0.19 0.1 0.32 1.23 (30%) 6.25 2.25 0.45 0.38 0.40 0.42 0.22 0.72 (50%) 13.88 5 2.22 0.85 0.90 0.95 0.5 1.6 6.17 16.31 5.87 2.61 1.17 1.06 1.11 0.58 1.88 7.25 15.27 5.5 2.44 0.93 1.04 0.55 1.76 6.79 Furnace Oil (50%) 14.58 5.25 2.33 1.05 0.89 0.52 1.68 6.48 LPG (50%) 27.77 10 4.44 2 1.70 1.81 1.90 3.2 12.34 Biogas (50%) 8.68 3.12 1.38 0.62 0.53 0.56 0.59 0.31 3.85 (90%) 0.81 0.13 0.14 0.15 0.08 0.25

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

Potential of renewable energy sources in India
Cumulative achievements as on Potential of renewable energy sources in India No. Sources / Systems Achievements during Cumulative Achievements I. Power From Renewables A. Grid-interactive renewable power 1. Biomass Power (Agro residues) 77.50 MW MW 2. Wind Power MW MW 3. Small Hydro Power (up to 25 MW) MW MW 4. Cogeneration-bagasse MW MW 5. Waste to Energy 3.66 MW MW 6. Solar Power 2.12 MW Sub Total (in MW) (A) 1, MW 13, MW B. Off-grid/Distributed Renewable Power (including Captive/CHP plants) 7 Biomass Power / Cogen.(non-bagasse) 60.92 MW MW 8. Biomass Gasifier 8.98 MWeq. 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 MWeq Total ( A + B ) MW 14, MW

300/NIL Villages/Hamlets
II. Remote Village Electrification 300/NIL Villages/Hamlets 4254 villages 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 energy from the Sun
Coal is the remains of prehistoric trees.

Solar Photovoltaic Lighting
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 pumping Solar 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 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.

Biomass 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-gas Two models of bio-gas plants are being constructed. Low cost “Deenabandu” model for individual families Floating 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-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 ,000 M.W. Biomass ,000 M.W. Co-generation ,000 M.W. Mini Hydel ,000 M.W. Municipal / Industrial waste - 5,000 M.W. 1,22,000 M.W.

Alternative Energy

What do we mean by Alternative Energy?
Electric Utilities Wind Energy Fuel Cells Today I will provide you with insights to the five key drivers of market demand for alternative energy, the ways available to you to participate in alternative energy investment, and why Calvert’s approach to investing stands apart from the others. Before we discuss the five key drivers of demand for alternative energy, you might have the simple question: what is alternative energy? When we refer to alternative energy, we’re generally speaking about companies involved in developing technologies that reduce our reliance on traditional fossil fuels. This could include companies involved with 1) new energy sources (e.g., wind, solar, bioenergy, geothermal,wave/tidal power, and small-scale hydro), 2) conservation and efficiency technologies (e.g., energy efficient lighting, efficient engines/turbines), or 3) storage mechanisms (e.g., fuel cells, hydrogen generation and storage batteries). Calvert believes the alternative energy sector is comprised of eight distinct categories or industries that appear poised for growth (some of the most well-known are pictured here on the slide). The eight categories are: WIND, SOLAR, FUEL CELLS, BIOFUELS, GEOTHERMAL, OCEAN, HYDRO, CONSERVATION/EFFICIENCY Solar Energy Bio Energy

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 currently very energy expensive
and very inefficient ……....but someday soon…..…

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.

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 ENERGY Tidal energy is the result of the Moon’s Gravitational attraction on Earth and the way the moon’s gravity pulls the oceans in a bulge as the Moon orbits Earth – the tide must raise the water at least 10 feet

Tides Governed by Earth-Moon-Sun
Greatest range occurs when sun and moon pull in same direction (spring tide) 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 Weakest when sun and moon in opposition (neap tide) North Pole Earth rotates counter-clockwise Tidal in stream energy occurs due to the moving mass of water with speed and direction as caused by gravitational forces of the sun and the moon on the earth's waters. Due to its proximity to the earth, the moon exerts roughly twice the tide raising force of the sun. Although the resource is intermittent, the occurrence of the resource is dependent only on the positions of the Earth, Moon and Sun and therefore is known indefinitely into the future. Therefore, owners will be able to sell Power with a firm guarantee Resource Variable but Predictable MOON’S ORBIT

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 Turbines Bulb turbine used at La Rance tidal plant on the Brittany coast in France

TIDAL ENERGY

TIDAL ENERGY ADVANTAGES: Reliable and Predictable
Clean Energy Alternative – Needs no Fuel Renewable 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 In 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 The largest increase in geothermal use in the United States in the past five years was in aquaculture pond and raceway heating.

How is geothermal energy created?
Wells are drilled into the geothermal reservoirs The first step is drilling wells into the geothermal reservoirs to bring the hot water to the surface. Then, once the hot water and/or steam travels up the wells to the surface, they can be used to generate electricity in geothermal power plants or for energy saving non-electrical purposes.

How is geothermal energy created?
Steam, heat, or hot water from reservoirs spin the turbine Used water is returned down an injection well In geothermal power plants steam, heat or hot water from geothermal reservoirs provides the force that spins the turbine generators and produces electricity. The used geothermal water is then returned down an injection well into the reservoir to be reheated, to maintain pressure, and to sustain the reservoir.

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.

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 Clean. Geothermal power plants, like wind and solar power plants, do not have to burn fuels to produce steam. Generating electricity with geothermal energy helps to conserve nonrenewable fossil fuels, and by decreasing the use of these fuels, we reduce emissions that harm our atmosphere. There is no smoky air around geothermal power plants . The land area required for geothermal power plants is smaller per megawatt than for almost every other type of power plant. Geothermal installations don't require damming of rivers or harvesting of forests Geothermal plants are always running 24/7 Power plants are build on top of the geothermal reservoir and there is no need to import fuels. Economic benefits remain in the region and there are no fuel price shocks.

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 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 The Challenges we will face are the high prices and the risky operations. Although geothermal project prices have decreased in the past drilling cost up to half the total price of the project. Discovering potentially geothermal reservoirs is difficult, Only about one in every five exploratory wells drilled being a valuable resource. Also plants must be located right above the reservoirs because energy will be lost when moving hot water and steam. Many of the best potential resources are located in remote or rural areas normally on federal or state lands. The productivity of geothermal wells may decline over time. As a result, it is crucial that developers manage the geothermal resource efficiently.

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 residents.

Magneto Hydro Dynamics (MHD)

-- provides insulation
INTRODUCTION Magnetic Field Effects: -- exerts a force (creates structure) -- provides insulation -- stores energy (released in flare)

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.

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

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.

Emitter Collector Heat Out Heat In Electron Current Load

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

SUMMARY Developments making TECs more feasible
Advances in electronic emitter materials New methods of plasma analysis by computer simulation Application of microminiaturisation techniques

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.

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

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 S 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.

Fuel Cell e- H+ H2 O2 H2  2H+ + 2e- ½ O2 + 2H+ + 2e-  H2O Anode
Cathode e- H+ H2 O2 H2  2H+ + 2e- ½ O2 + 2H+ + 2e-  H2O Electrolyte Overall: H2 + ½ O2  H2O

Membrane-Electrode Assembly (MEA)
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 electrolyte catalyst electrodes sealant Membrane-Electrode Assembly (MEA)

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 : 2H H+ + 4e- Cathode reaction : 2H2 + O H2O (vapour) + Energy

H2 is fed to one electrode and is absorbed
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
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.

Comparison between different types of fuel cells
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 Yes, Good Temperature match Oxidant Air to O2 Purified Air to O2 Air to enriched air Air Operational Temperature 65 – 85 ºC ºC ºC ºC ºC Distributed Generation system level (η %) Primary contaminate sensitivities CO,NH3 and sulphur CO,CO2 and sulphur CO < 1% sulphur Sulphur

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 Temperature sets operational parameters & fuel choice 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

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 ( C) 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 ( °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-d 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/Conversion Fuel Cell Car

Hydrogen as a future energy source

Reasons for change Reduction in greenhouse gases (CO2, NOx, SOx)
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

It’s not energy efficient!
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!

It may not be Environmentally friendly !
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

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 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.

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:  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

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

Energy Management vs Energy Conservation
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 and Financial Management
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 Management Benefits
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

Focusing Energy Management
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 Energy is used to achieve some benefit. Find the lowest cost means to reap that benefit.

Starting Your Energy Action Plan
Designate an Energy Management Coordinator Establish the Energy Management Team Evaluate cost saving opportunities Prioritize implementation Implement Evaluate success (e.g. benchmarking) and promote

Energy Management Coordinator
A single person Dynamic Goal oriented Good manager Wears other hats

GOALS OF THE EMC 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)

EXAMPLE ENERGY MANGEMENT GOALS
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

ENERGY MANAGEMENT TEAM
Energy Management Coordinator Technical Support Steering Group

Energy Management Conservation - reducing the amount we use by insulating, reducing the amount we use and additional control technology Recovery - using the so called waste - developed patent to recover heat from flue gasses on boiler flue systems Substitution - renewable technologies - wind (Scarborough), PV arrays (west campus)

Which factors does Energy Management deal with?
People Building Energy type used Installed equipment External factors Legislation – ‘One will have to comply’ People - the individuals who make choices about energy use and control the energy systems Building - insulation level, building type Energy type used - oil or gas …….emission factors Installed equipment - is the equipment energy efficient, condensing boilers, CFL lamps External factors - weather, wind speed, solar gain 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 Use in India 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 : Mtoe : Mtoe : 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 190

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) = kcal Quantity of heat required making the water into steam (Sensible heat + Latent heat) = 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

Waste Heat Recovery 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 condensate There are two basic ways to recover heat from the sources: 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). Waste heat boilers to produce steam.

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

BARRIERS/OBSTACLES TO MANAGEMENT OF ENERGY
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.

ENERGY MANAGEMENT The 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 INVOLVES FOUR 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 Feasibility Studies -Capital Intensive Projects Training Monitor Implement Higher-Cost Measures

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 use Understand how that energy is being used – and possibly wasted Identify 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.

Steps in the On-site Energy Audit
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

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

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 = Units For 1 year = 23 Units Cost =  Rs = Rs Cost = 23.0  Rs = Rs Cost saving for one year=Rs 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

Wave length (micrometers)
UV Visible Infrared Energy 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 /500 lx Corridor /500 lx Classroom lx Restroom lx Living room - 50/300 lx Bedroom lx Luminous 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/s where, 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

Spot light d b 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 (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 systems
Type of light source Energy 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 12 0.05 l/h 488 100 0.25 Pressure lamp 0.06 l/h 563 220 0.39 Poor 0.08 l/h 813 1300 1.60 Gas lamp LPG 28 l/h 350 330 0.94 34 l/h 425 1000 2.35 Biogas lamp Biogas 0.10 m3/h 639 0.48 0.20 m3/h 1385

Examples of electrical lamps
Incandescent lamp Electrical 100W 100 1200 12 Good 1 Halogen lamp 25W 25 500 20 2 Fluorescent tube 13W 13 585 45 (*) – 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 lm)

SUSTAINABLE ENERGY Unit 2.

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