solar thermal power plants, many solar panels are used to concentrate sun rays, to heat up water into steam. The steam is used to run the turbines to produce electricity. A capacity of litres solar heater can save upto units of electricity per year. Advantages of Solar Energy (i) It is available in abundance in our country and is free of cost.
(ii) It is a renewable source of energy. (iii) It can be used for generating electricity or heat. (iv) It does not cause pollution. .
. Biogas Biogas is the mixture of methane (nearly %), hydrogen sulphide, carbon dioxide and hydrogen. It is produced by the decomposition of animal wastes (cow dung) and plant wastes in the absence of oxygen. It is also commonly called as ‘ Gobar gas ’ since the starting material used is cow dung which means gobar in Hindi.
Uses of biogas (i) It is used as fuel for cooking . (ii) It is used to run motors and pump sets. (iii) It is used to generate electricity. Advantages of biogas (i) It burns without smoke and therefore causes less pollution.
(ii) An excellent way to get rid of organic wastes like bio-waste and sewage material. (iii) Left over slurry is a good manure rich in nitrogen and phosphorus (iv) It is safe and convenient to use (v) It can reduce the amount of greenhouse gases emitted. Environmental Management . .
Shale gas Shale refers to the soft finely stratified sedimentary rock that is formed from the compaction of small old rocks containing mud and minerals – such as quartz and calcite, trapped beneath earth’s surface. These rocks contain fossil fuels like oil and gas in their pores. The fuel is extracted by a technique called hydraulic fracturing (drilling or well boring of sedimentary rocks layers to reach productive reservoir layers ) . Environmental concerns of shale gas (i) Shale drilling could affect groundwater reserves, which can contaminate the drinking water resources and also affect the fertility of the soil.
(ii) Million gallons of water is