ENERGY AND ENVIRONMENTS. Dharumarajan Scientist National Bureau of soil survey and land use planning Regional Centre, Hebbal, Bangalore-24 The Industrial Revolution of the 19th century ushered in new technologies. The spurt in inventions in that century was unprecedented in many ways. Some of these inventions involved use of natural resources like coal and oil. The thought of exhaustible nature of these resources and the environmental damage from the use of these resources never occurred either to the inventors or the subsequent generations. In the quest to sustain galloping economic activity, the dependence on coal and oil has soared at a phenomenal rate over the years. The burnt fuels result in the release of carbon dioxide and other gases into the atmosphere causing environmental damage. It has become imperative to look at energy technology with a new perspective. There are abundant renewable sources of energy such as wind, sun, water, sea, biomass apart from even daily wastes. These sources are pollution free and hence clean energy apart from being unlimited/ inexhaustible. The country is endowed with large amount of sustainable resource base and nonconventional energy technologies, which are well suited for grid connected power generation; energy supplies in remote areas which are not/ could not be connected to the grid and for captive consumption. Nonconventional energy sources like wind energy, solar energy through thermal as well as photovoltaic system, biomass and hybrid sources will help to a great extent in enhancing power generation capacity. Hence appropriate policies and programmes that optimize the use of available energy resources with new technologies have to be propagated, promoted and adopted, if necessary, by budgetary support. 1 Renewable energy is derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources The threat of global warming is causing a lot of concern. While there are controversies and differences of opinion about it there is a general consensus that, as a precautionary measure, emission of greenhouse gases should be restrained as much as possible. This consensus is, however, qualified in two ways: (1) The measures undertaken must not impede economic development in the present developing countries and delay fulfilling the basic needs of that 40% of mankind now without access to commercial energy. (2) They must not prevent the maintenance of a strong and healthy economy in the present industrialized countries. For it is only by mitigating the present poverty and misery that hopes of a peaceful world can be realised in the long term and only in a strong and healthy global economy can a sound world environment thrive. Basically, a slow-down in the growth of carbon dioxide emissions can be achieved in the following ways: by more efficient energy use (achieving the same results with less energy); by fuel switching, from carbon-rich fossil fuels to others with lower carbon content, e.g. from coal to natural gas; by switching from fossil fuels to nuclear and renewables; by the capture and disposal of CO2 to prevent it from reaching the atmosphere Electricity Generation from Four "New" Energy Resources in 1993 Energy Resource Generation GWh/a Geothermal 37,976 % 85.6 Generation in 1993 Capacity MW 6,456 % 60.9 Capacity factor % 67.1 2 Wind Solar Tidal Total 4,878 897 601 44,352 11.0 2.0 1.4 3,517 366 261 33.2 3.4 2.5 15.8 28.0 26.3 100.0 10,600 100.0 47.8 Survey of Energy Resources 17th Edition, WEC 1995 (Geothermal in 1994). Wind power Airflows can be used to run wind turbines. Modern wind turbines range from around 600kW to up to 5 MW of rated power, although turbines with rated output of 1.53 MW have become the most common for commercial use. The power output of a turbine is a function of the cube of the wind speed, so as wind speed increases, power output increases dramatically. Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms. Wind power is the fastest growing of the renewable energy technologies, though it currently provides less than 0.5% of global energy. Over the past decade, global installed maximum capacity increased from 2,500 MW in 1992 to just over 40,000 MW at the end of 2003, at an annual growth rate of near 30%.Due to the intermittency of wind resources, most deployed turbines in the EU produce electricity an average of 25% of the hours in a year (a capacity factor of 25%), but under favourable wind regimes some reach 35% or higher. Capacity factors are a function of seasonal wind fluctuations and may be higher in winter. It would mean that a typical 5 MW turbine in the EU would have an average output of 1.7 MW. Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand. This could require large amounts of land to be utilized for wind turbines, particularly in areas of higher wind resources. Offshore resources experience mean wind speeds of ~90% greater than that of land, so offshore resources could contribute substantially more energy. This number could also increase with higher altitude ground-based or airborne wind turbines. Wind strengths near the Earth's surface vary and thus cannot guarantee continuous power unless combined with other energy sources or storage systems. Some estimates 3 suggest that 1,000 MW of conventional wind generation capacity can be relied on for just 333 MW of continuous power. While this might change as technology evolves, advocates have suggested incorporating wind power with other power sources, or the use of energy storage techniques, with this in mind. It is best used in the context of a system that has significant reserve capacity such as hydro, or reserve load, such as a desalination plant, to mitigate the economic effects of resource variability. Wind power is renewable and produces no greenhouse gases during operation, such as carbon dioxide and methane. Environmental challenges Environmental Issues Wind plants produce no air pollutants or GHGs. However, concerns have been raised about bird kills. Bird kills are not likely to be a problem in most areas; where they are a problem, this will probably be dealt with largely by restrictions on wind-farm sitting in bird migration pathways or in dense avian population centers, although technical fixes (e.g., use of tubular towers to reduce perching) can also reduce the bird-kill potential. Other concerns are noise and aesthetic impacts. Engineering innovations have reduced noise levels to the extent that noise is a problem only if turbines are sited within a few hundred yards of a residence. Aesthetic concerns will tend to be offset—in many areas— by the royalty payments from wind power producers, which in the Great Plains could be comparable to land rents for croplands. Biofuel Plants use photosynthesis to grow and produce biomass. Also known as biomatter, biomass can be used directly as fuel or to produce liquid biofuel. Agriculturally produced biomass fuels, such as biodiesel, ethanol and bagasse (often a by-product of sugar cane cultivation) can be burned in internal combustion engines or boilers. Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work. Liquid biofuel is usually either a bioalcohol such as ethanol or a bio-oil such as biodiesel and straight vegetable oil. Biodiesel can be used in modern diesel vehicles with little or no modification to the engine and can be made from waste and virgin vegetable and animal oil and fats (lipids). Virgin vegetable oils can be used in modified diesel engines. In fact the Diesel engine was originally designed to run 4 on vegetable oil rather than fossil fuel. A major benefit of biodiesel is lower emissions. The use of biodiesel reduces emission of carbon monoxide and other hydrocarbons by 20 to 40%. In some areas corn, cornstalks, sugarbeets, sugar cane, and switchgrasses are grown specifically to produce ethanol (also known as grain alcohol) a liquid which can be used in internal combustion engines and fuel cells. Ethanol is being phased into the current energy infrastructure. E85 is a fuel composed of 85% ethanol and 15% gasoline that is sold to consumers. Biobutanol is being developed as an alternative to bioethanol. In the future, there might be bio-synthetic liquid fuel available. It can be produced by the Fischer-Tropsch process, also called Biomass-To-Liquids (BTL). Direct use is usually in the form of combustible solids, either wood, the biogenic portion of municipal solid waste or combustible field crops. Field crops may be grown specifically for combustion or may be used for other purposes, and the processed plant waste then used for combustion. Most sorts of biomatter, including dried manure, can actually be burnt to heat water and to drive turbines. Sugar cane residue, wheat chaff, corn cobs and other plant matter can be, and are, burned quite successfully. The net carbon dioxide emissions that are added to the atmosphere by this process are only from the fossil fuel that is often currently consumed to plant, fertilize, harvest and transport the biomass. Processes to harvest biomass from short-rotation poplars and willows, and perennial grasses such as switchgrass, phalaris, and miscanthus, require less frequent cultivation and less nitrogen than from typical annual crops. Pelletizing miscanthus and co-firing it with coal for generating electricity is being studied and may be economically viable.[27] The higher heating value of cellulose is about 17.4 MJ/kg. The estimated yield of ethanol from dry cellulose is about 0.2 kg of ethanol per kg of cellulose (60 gal/ton). Since the higher heating value of ethanol is 29.7 MJ/kg of ethanol it would be 5.94 MJ/kg of the cellulose that it is made from. Thus the ethanol contains only about 1/3 as much energy as the cellulose that it was made from. Co-firing cellulose with coal would replace about three times as much fossil fuel as using the cellulose to make ethanol. The replaced coal would produce 0.0946 kg CO2/MJ while the replaced liquid fuel would produce only about 0.0733 kg CO2/MJ so co-firing the cellulose with coal is about 3.8 times more effective at reducing CO2 emissions than using it to make ethanol. 5 Environmental Issues When biomass is grown at the rate it is used for energy, there are no net CO2 emissions from the biomass; life-cycle CO2 emissions (associated mainly with fossil fuel use for biomass growing, harvesting, transport, and processing) can be relatively high for options with poor economic prospects (e.g., cornderived ethanol) but are generally low for options with good economic prospects (e.g., ethanol derived from cellulosic feedstocks). When perennial grasses or short rotation woody crops (SRWCs) are grown as energy crops on excess agricultural lands the local environment can be improved relative to prior land use growing annual row food crops. Such energy crops, well managed, can help control erosion, can act as filters to reduce runoff of agricultural chemicals, and can offer better wildlife protection—with energy croplands potentially serving directly as habitat or as buffers around, or corridors between, fragments of natural habitat. But environmental conditions would improve even more if excess croplands were instead converted into natural wildlife habitat. Likewise, conversion of natural habitat to the production of biomass energy crops would harm local habitat. Air pollutant emissions in conversion to useful energy forms and energy services depend on the conversion technologies involved, except that biomass conversion is generally characterized by very low SO2 emissions, owing to the low sulfur content of biomass. Gasification-based power-generating technologies now under development will have low emissions of all local pollutants, except in some cases NOx emissions arising from fuel-bound nitrogen, which might require the use of emission control equipment. Ethanol blends with gasoline in internal combustion engine vehicles are not expected to provide air quality benefits in excess of what can be provided by reformulated gasoline, and neat ethanol used in internal combustion engine cars would be only marginally better. But dramatic reductions in local airpollutant emissions relative to gasoline internal combustion engine cars would probably be realizable with alcohol-powered fuel cell cars, and air pollutant emissions would be zero for fuel cell cars powered by biomass-derived hydrogen. Geothermal energy 6 Geothermal energy is energy obtained by tapping the heat of the earth itself, usually from kilometers deep into the Earth's crust. It is expensive to build a power station but operating costs are low resulting in low energy costs for suitable sites. Ultimately, this energy derives from heat in the Earth's core. The government of Iceland states: "It should be stressed that the geothermal resource is not strictly renewable in the same sense as the hydro resource." It estimates that Iceland's geothermal energy could provide 1700 MW for over 100 years, compared to the current production of 140 MW.The International Energy Agency classifies geothermal power as renewable. Three types of power plants are used to generate power from geothermal energy: dry steam, flash, and binary. Dry steam plants take steam out of fractures in the ground and use it to directly drive a turbine that spins a generator. Flash plants take hot water, usually at temperatures over 200 °C, out of the ground, and allows it to boil as it rises to the surface then separates the steam phase in steam/water separators and then runs the steam through a turbine. In binary plants, the hot water flows through heat exchangers, boiling an organic fluid that spins the turbine. The condensed steam and remaining geothermal fluid from all three types of plants are injected back into the hot rock to pick up more heat. The geothermal energy from the core of the Earth is closer to the surface in some areas than in others. Where hot underground steam or water can be tapped and brought to the surface it may be used to generate electricity. Such geothermal power sources exist in certain geologically unstable parts of the world such as Iceland, New Zealand, United States, the Philippines and Italy. The two most prominent areas for this in the United States are in the Yellowstone basin and in northern California. Iceland produced 170 MW geothermal power and heated 86% of all houses in the year 2000 through geothermal energy. Some 8000 MW of capacity is operational in total. There is also the potential to generate geothermal energy from hot dry rocks. Holes at least 3 km deep are drilled into the earth. Some of these holes pump water into the earth, while other holes pump hot water out. The heat resource consists of hot underground radiogenic granite rocks, which heat up when there is enough sediment between the rock and the earths surface. Several companies in Australia are exploring this technology. 7 Solar energy use In this context, "solar energy" refers to energy that is collected from sunlight. Solar energy can be applied in many ways, including to: Generate electricity using photovoltaic solar cells. Generate electricity using concentrated solar power. Generate electricity by heating trapped air which rotates turbines in a Solar updraft tower. Heat buildings, directly, through passive solar design. Heat foodstuffs, through solar ovens. Heat water or air for domestic hot water and space heating needs using solarthermal panels. Heat and cool air through use of solar chimneys. Generate electricity in geosynchronous orbit using solar power satellites Electricity is produced with zero pollutant and GHG emissions. Emissions associated with the manufacture of PV systems are small for the most promising PV technologies, largely because the energy required for manufacture is a small fraction of the energy produced over the system lifetime. Constraints and opportunities Critics suggest that some renewable energy applications may create pollution, be dangerous, take up large amounts of land, or be incapable of generating a large net amount of energy. Proponents advocate the use of "appropriate renewables", also known as soft energy technologies, as these have many advantages. There is no shortage of solar-derived energy on Earth. Indeed the storages and flows of energy on the planet are very large relative to human needs. The amount of solar energy intercepted by the Earth every minute is greater than the amount of energy the world uses in fossil fuels each year. Tropical oceans absorb 560 trillion gigajoules (GJ) of solar energy each year, equivalent to 1,600 times the world’s annual energy use. The energy in the winds that blow across the United States each year could produce more than 16 billion GJ of electricity—more than one and one-half times the electricity consumed in the United States in 2000. 8 Annual photosynthesis by the vegetation in the United States is 50 billion GJ, equivalent to nearly 60% of the nation’s annual fossil fuel use. The challenge of variable power supply may be further alleviated by energy storage. Available storage options include pumped-storage hydro systems, batteries, hydrogen fuel cells, and thermal mass. Initial investments in such energy storage systems can be high, although the costs can be recovered over the life of the system. Wave energy is continuously available, although wave intensity varies by season. A wave energy scheme installed in Australia generates electricity with an 80% availability factor. India is a growing giant facing the critical challenge of meeting a rapidly increasing demand for energy. With over a billion people, a fifth of the world population, India ranks sixth in the world in terms of energy demand. Its economy is projected to grow 7%-8% over the next two decades, and in its wake will be a substantial increase in demand for oil to fuel land, sea, and air transportation. While India has significant reserves of coal, it is relatively poor in oil and gas resources. Its oil reserves amount to 5.9 billion barrels, (0.5% of global reserves) with 9 total proven, probable, and possible reserves of close to 11 billion barrels. The majority of India's oil reserves are located in fields offshore Bombay and onshore in Assam. Due to stagnating domestic crude production, India imports approximately 70% of its oil, much of it from the Middle East. Its dependence is growing rapidly. The World Energy Outlook, published by the International Energy Agency (IEA), projects that India's dependence on oil imports will grow to 91.6% by the year 2020. Concerned about its growing reliance on oil from the Persian Gulf - 65% of its energy is imported from the region - India is following in the footsteps of other major oil importing economies, and seeking oil outside the Gulf. Indian firms' investment in overseas oilfields is projected to reach $3 billion within a few years. Of particular interest is Africa, especially Sudan, where India has invested $750 million in oil, and Nigeria, with which India reached a deal last November enabling it to purchase about 44 million barrels of crude oil per year on a long term basis. Additionally, India recently finalized a contract in Syria for the exploration, development and production of petroleum with a Syrian company. Sakhalin, in Russia, and Vietnam and Myanmar in Southeast Asia are also potential suppliers to the Indian market. Hydrogen (H2) is being aggressively explored as a fuel for passenger vehicles. It can be used in fuel cells to power electric motors or burned in internal combustion engines (ICEs). It is an environmentally friendly fuel that has the potential to dramatically reduce our dependence on foreign oil, but several significant challenges must be overcome before it can be widely used. Produced Domestically. Hydrogen can be produced domestically from several sources, reducing our dependence on petroleum imports. Environmentally Friendly. Hydrogen produces no air pollutants or greenhouse gases when used in fuel cells; it produces only NOx when burned in ICEs. Ocean energy Tidal Energy Tides are caused by the gravitational pull of the moon and sun, and the rotation of the earth. Near shore, water levels can vary up to 40 feet. Only about 20 locations have 10 good inlets and a large enough tidal range- about 10 feet- to produce energy economically. The simplest generation system for tidal plants involves a dam, known as a barrage, across an inlet. Sluice gates on the barrage allow the tidal basin to fill on the incoming high tides and to empty through the turbine system on the outgoing tide, also known as the ebb tide. There are two-way systems that generate electricity on both the incoming and outgoing tides. Tidal barrages can change the tidal level in the basin and increase turbidity in the water. They can also affect navigation and recreation. Potentially the largest disadvantage of tidal power is the effect a tidal station can have on plants and animals in the estuaries. There are currently two commercial sized barrages in operations. One is located in La Rance, France; the other is in Annapolis Royal, Nova Scotia, Canada. The US has no tidal plants and only a few sites where tidal energy could be produced economically. France, England, Canada, and Russia have much more potential. Tidal fences can also harness the energy of tides. A tidal fence has vertical axis turbines mounted in a fence. All the water that passes is forced through the turbines. They can be used in areas such as channels between two landmasses. Tidal fences have less impact on the environment than tidal barrages although they can disrupt the movement of large marine animals. They are cheaper to install than tidal barrages too. A tidal fence is planned for the San Bernardino Strait in the Philippines. Tidal turbines are a new technology that can be used in many tidal areas. They are basically wind turbines that can be located anywhere there is strong tidal flow. Because water is about 800 times denser than air, tidal turbines will have to be much sturdier than wind turbines. They will be heavier and more expensive to build but will be able to capture more energy. Wave Energy Waves are caused by the wind blowing over the surface of the ocean. There is tremendous energy in the ocean waves. The total power of waves breaking around the world’s coastlines is estimated at 2-3 million megawatts. The west coasts of the US and Europe and the coasts of Japan and New Zealand are good sites for harnessing wave 11 energy. One way to harness wave energy is to bend or focus the waves into a narrow channel, increasing their power and size. The waves can then be channeled into a catch basin or used directly to spin turbines. There are no big commercial wave energy plants, but there are a few small ones. Small, on-shore sites have the best potential for the immediate future; they could produce enough energy to power local communities. Japan, which imports almost all of its fuel, has an active wave-energy program. Ocean Thermal Energy Conversion (OTEC) The energy from the sun heats the surface water of the ocean. In tropical regions, the surface water can be 40 or more degrees warmer than the deep water. This temperature difference can be used to produce electricity. The OTEC system must have a temperature difference of at least 25 degrees Celsius to operate, limiting use to tropical regions. Hawaii has experimented with OTEC since the 1970’s. There is no large-scale operation of OTEC today. There are many challenges. First, the OTEC systems are not very energy efficient. Pumping water is a giant engineering challenge. Electricity must also be transported to land. It will probably be 10 to 20 years before the technology is available to produce and transmit electricity economically from OTEC systems. Hydrogen fuel The best pollution-free alternative to batteries while still using clean electric motors is the hydrogen fuel cell. Hydrogen-powered "fuel cells hold enormous promise as a power source for a future generation of cars" They do not have the restraints that batteries do, either. Hydrogen is consumed by a pollution-free chemical reaction--not combustion--in a fuel cell. The fuel cell simply combines hydrogen and oxygen chemically to produce electricity, water, and waste heat (MacKenzie 62-3). Nothing else. And hydrogen is the most abundant element in the universe, constituting about 93% of all atoms. "It is found in water (H20), fossil fuels (basically, compounds of hydrogen and carbon), and all plants and animals" (61). "What better replacement for finite, nonrenewable gasoline?" 12 (Zygmont 20). "Hydrogen has often been called the perfect fuel. Its major reserve on earth (water) is inexhaustible. The use of hydrogen is compatible with nature, rather than intrusive. We will never run out of hydrogen" (NHA). Hydrogen can be obtained from water by the process of electrolysis, or splitting water molecules using electricity. We cannot, however, forget the external effects of getting the electricity from power plants. Many power plants across the country, producing electricity to charge batteries or to produce hydrogen, run on carbon-based fuels, such as coal, and therefore produce emissions (MacKenzie 61-2). Here in Spokane, however, where our electricity comes from the water-powered generators at Washington Water Power, this is not a problem, and hydrogen-fuel-cell-powered vehicles can be truly emission free. The fuel cells are compatible with the cold winters we have in Spokane. There are several types of fuel cells, but the one most suited for cars is called the proton-exchange membrane (PEM) fuel cell. Some of its main features are its ability to start quickly and to run at moderate temperatures (150° instead of 1,900°, like some other versions), which will help because it does not need to heat up very much in order to run. The PEM fuel cell is compact and lightweight: a big advantage for cars. Furthermore, its maximum efficiency of 60% (energy delivered from hydrogen to motor as electricity) is about 3 times greater than the efficiency of internal combustion engines (most of the energy from combustion is lost in heat and friction before it even pushes down on the pistons) (Cannon 119, 112). The range of fuel-cell-powered vehicles is not limited by batteries, but by the amount of fuel in the storage tank. Recent developments in hydrogen storage technology have come up with "carbon-adsorption" systems. These are refrigerated and pressurized tanks that can store massive amounts of hydrogen. Calculations estimate that over 7 gallons of hydrogen could be stored in a single gram of this new material. This allows a range of nearly 5,000 miles from a single tank! (Hill 20). These tanks would weigh less than 200 pounds, occupy about half the amount of space used by current gasoline tanks (H&FCL), 13 and could be refueled in 4-5 minutes (MacKenzie 75). The carbon-adsorption tanks would also work well in Spokane's cold winters, as the process improves greatly as the temperature decreases. This tank could easily become the storage method of choice if research, improvements, and advancements continue (75). Even if nothing came from these or future developments, the current "range for hydrogen fuel cell vehicles is comparable to that for gasoline internal combustion engine vehicles" (Winkler). Reference Casten et al. 1997: S. Casten, M. Laser, J. Romero, B. Hirokawa, J. Braciak, R. Ross, R.G. Herst, andL. Lynd: “Costs and features of advanced biomass ethanol/electricity generation technology”. Poster paper presented at Making a Business from Biomass in Energy, Environment, Chemicals, Fibers, and Materials, Third Biomass Conference of the Americas, Montreal, Canada, 24-29 August 1997. Mock et al. (1998): J.E. Mock, J.W. Tester, and P.M. Wright, “Geothermal Energy From the Earth: Its Potential Impacts as an Environmentally Sustainable Resource,” Annual Reviews of Energy and the Environment 22: 305-356 AR-039-10 (1998). WEC 1994: World Energy Council, New Renewable Energy Resources)A Guide to the Future, (London, UK: Kogan Page, 1994). India Ministry of Non-Conventional Energy Sources (MNES) http://mnes.nic.in/ The Energy & Resources Institute (TERI) http://www.teriin.org/ Centre for Wind Energy Technology www.cwet.tn.nic.in 14 15