Sun ray heat can be absorbed in water of the Solar Pond. The surface of water is covered with thin layer of oil to prevent heat loss due to evaporation. Heat absorbed by water is used for various purposes.
Atomic energy: Tremendous energy in the form of heat is released during nuclear fission while the atom is split by neutron collision. This heat is used for producing steam and running turbine generator set to get electricity. Suitable material like uranium is available under the earth. It is processed to make it suitable for use in atomic reactors. Normally it is not operated in regulation mode for safety reasons.
Hydrogen energy: Raw energy source is hydrogen gas. It can be obtained by electrolysis of water. Ample water is available freely. So, it may be cheaper, but production, storage and handling cost are hurdles for economic viability. It is used in two ways.
Hydrogen cell: Hydrogen cell converts it directly to electricity by chemical reaction.
Hydrogen fuel: Hydrogen is used as fuel in IC engines. This mechanical energy is used to run vehicles or as prime mover to run generator to get electricity.
Biomass energy: Raw energy source is waste like agricultural, industrial, municipal, animal manure, etc. These are either burned directly to produce heat to electricity by conventional way. Sometimes it is converted to biogas in gasifier or by bacterial decomposition and is used for electricity or other heating purposes. Some special crop is grown to get oil like bio diesel from Jojoba. Sometimes it is converted to solid pellets to burn with other fuels. This is possible on a small scale due to the limitation of inputs.
Ocean wave energy: Ocean wave is a continuous process and is use or lose type source. There are two types of wave movements and accordingly devices are designed to trap the energy.
- Up down movement: Floaters at fixed place on surface of water moves up and down with crest and trough passing under it. This movement is ultimately converted to electricity.
- Travelling movement: Water wheel half submerged in water at fixed place rotates by push of travelling wave. This movement is ultimately converted to electricity.
Ocean Tidal Energy: Ocean water rises and falls regularly over the day and month. A specially built tank at the bank of sea will get in water by spilling over during tide. The water turbine is run by this water during ebb as water level of sea is lower than tank. Energy available is for short period.
In case of double tank set up, the first tank gets in water during tide period as above. During tide period when water in the first tank reach particular level, water turbine between first tank to second tank is operated to get electricity. So, generation is possible during tide period also. During ebb period when water level difference between second tank and sea is sufficient, the turbine between second tanks to sea is operated and energy is available. This is an impermanent source of energy.
Geothermal: Heat from the deep earth is utilized to get energy. Suitable liquid is injected through pipe in the deep bore on the earth. The bottom of pipe remains submerged in the liquid at bottom. This liquid is converted to vapour and comes up through other pipelines to run turbine generator set to get electricity.
Ocean thermal: Surface water temperature is high compared to deep sea temperature. Liquid of low boiling point like ammonia is evaporated in heat exchanger using surface water. Vapour is used to run turbine generator set and exhaust is cooled down in heat exchanger using deep sea water.
Lightning: Lightning is also a source of energy. But tremendous energy is available only for very short period. Location, quantity and time when it is available is uncertain and unpredictable. Hence capturing it is very difficult. One option can be floating collector and converters in the sky can collect and convert to high frequency electromagnetic wave targeting to receiving station on earth.
Concluded
Natvar D. Makwana is a Retired Engineer from SLDC, Gotri Baroda, Gujarat. Post retirement, he has been working as a visiting faculty of Parul Institute of Engineering and
Technology. He was associated with various taskforces /committees related to power system operation at state/ regional/national level. He is a Fellow of Institution of Engineers, India (IE) and a Fellow of Society of Power Engineers (CBIP).
Paresh R. Modha is working as an Assistant Professor in the Department of Electrical Engineering, ADIT, New Vallabh Vidyanagar. He received his M.E. in Electrical Engineering,
specialized in Electrical Power Systems, from Birla Vishwakarma Mahavidyalaya (BVM), Gujarat Technological University, Ahmedabad in 2011. At present he is perusing Ph D from CVM University, Vallabh Vidyanagar.
