1. BasisTypes Availability and usage with respect to time and economical viability. Conventional and non- conventional energy resources. Possibility of renewability.Renewable and non renewable energy resources. Classification of energy sources: Energy can be classified into several types based on the following criteria as: Primary and Secondary energy Commercial and Non commercial energy Renewable and Non-Renewable energy

3. Advantages and Disadvantages of Renewable energy Advantages Available in plenty in nature and inexhaustible. These can be built as close as possible to the point of consumption and transmission losses can be minimised. The available technologies are more flexible and highly diverse. A good amount of variation is possible in the energy quality. Locally available renewable energy can be fully utilised

4. Disadvantages Concentration of these resources is limited to certain regions. Supply is intermittent and also varies seasonally. Cost of the equipment to harness these resources is comparatively higher than those of the conventional energy sources. Some of the components like solar cells, auto tracking systems, concentrators etc., all require very high technology. Need for storage system to store energy when the supply is available in plenty and to use when the supply is inadequate or absent.

5. Advantages and disadvantages of conventional energy sources Advantages: Fully developed technology is available to harness this energy. Cost of generation has been brought down to affordable levels. They can be easily transported to any place. Ideal for small applications.

6. Disadvantages: They are polluting because of their emissions. Their availability is reducing as they are in limited quantity in nature and these sources are depleting at a fast pace. They are leading to lot of ecological imbalances. They are usually far off from the point of consumption

8. Coal 1)Peat : a) Spongy humified substance. b) 80% moisture; upon air drying 20%. c) burns with odour and smoky flame. d) free burning fuel 2) Lignite: a) Brown in colour, woody structure. b) 40 % moisture; upon drying 10% c) brown coal

9. 3)Bituminous coal: a) Most popular form of coal. b)4 to 6 % moisture; 75 to 90 % Carbon c) weather resisting and burns with yellow flame d) 20 to 30% volatiles. Coking and non-Coking Coking: softens and swells upon heating. Turns into Pasty mass. Coke and gas production. Non-Coking: 78 to 84% carbon; does not become soft. Burns with little or no smoke.; steam power plants.

10. 4)Anthracite Coal: a) 90 % carbon; b) no volatiles ; so difficult to burn compared to bituminous coal. c) burns with short flame ; does not fuse.

12. R/P Ratio of a non-renewable energy resource: The Reserves-to-production ratio (RPR or R/P) is the remaining amount of a non-renewable resource, expressed in years. While applicable to all natural resources, the RPR is most commonly applied to fossil fuels, particularly petroleum and natural gas. RPR = (amount of known reserves) / (amount used per year) The reserve portion of the ratio is the amount of a resource known to exist in an area and to be economically recoverable (proved reserves). The production portion of the ratio is the amount of resource used in one year at the current rate.

13. Coal The proven global coal reserve was estimated to be 9,84,453 million tonnes by end of 2003. The USA had the largest share of the global reserve (25.4%) followed by Russia (15.9%), China (11.6%). India was 4th in the list with 8.6%.

14. Oil The global proven oil reserve was estimated to be 1147 billion barrels by the end of 2003. Saudi Arabia had the largest share of the reserve with almost 23%. (One barrel of oil is approximately 160 litres)

15. Gas The global proven gas reserve was estimated to be 176 trillion cubic metres by the end of 2003. The Russian Federation had the largest share of the reserve with almost 27%. (*Source: BP Statistical Review of World Energy, June 2004) World oil and gas reserves are estimated at just 45 years and 65 years respectively. Coal is likely to last a little over 200 years

17. Fuel cell

21. Solar Energy