Why Alternative Sources • Fossil fuels are limited • They add to pollution • The carbon dioxide concentration has gone up by -50 % over the past 100 years Alternate Energy Sources In addition to the conventional sources, we now have some more sources, even if with limited production: Solar energy: The present efficiency of the conversion of solar energy into electricity being low, the cost of solar panels and batteries being high and free space shrinking, there are limitations. The disposal of the old panels and batteries is an additional problem but the generation is quite pollution free. Wind energy: Germany leads (rather than Denmark whose name seems to remind everyone of wind turbines) and India has a huge potential of 45,000 MW of wind driven units. In Gujarat and Maharashtra, major projects have been undertaken. Bio Fuels: Ethanol and methanol are being used as additives, independent energy sources or fuel for the cells. But the dilemma of farmers remains: To grow corn or wheat! Tidal energy: The tapping of tidal energy is an attractive idea but so far very limited efforts have been made. Fuel cells using ethanol: In fuel cells, hydrogen is flown to the anode where a platinum catalyst (platinum powder coated on cloth or paper) breaks it into electrons and positive ion. Polymer Electrolyte Membrane is used to filter the positive ions through. These two travel through different parts of circuit and meet with oxygen at cathode to form water and energy. Hydrogen: Burning of hydrogen as fuel produces energy and water. So obviously it's a 100% pollution- free fuel. Scenario. The process of producing hydrogen is itself quite polluting and the over -all- efficiency is not very different from hydrocarbons. Gas hydrates: At the ocean bottom, there are huge frozen deposits of gas hydrates made of gases like methane. These are valuable as fuel and hydrogen source. Coal Bed Methane: By virtue of being highly porous, coal has tremendous gas absorption potential. Under the surface,there are coal deposits storing huge amount of methane. Tapping it can be a precious energy source. Geochemical energy, Geothermal energy etc. are also promising. While nuclear fusion is the most promising, it's still a long way. For a common man, planting trees,sharing vehicles, saving on consumption of electricity, more efficient public transport system are the best routes to take. The scientists and technologists will continue to search for more energy- efficient gadgets, more environment friendly ways to produce hydrogen and make fuel efficient cars.