The efficiencies of all modern thermal power generating system lies between 35-40% as they have to reject large quantities of heat to the environment. In all other conventional power plant, first the thermal energy of the gas is directly converted in to electrical energy. Hence it is known as direct energy conversion system.
The MHD power plants are classified in to Open and Closed cycle based on the nature of processing of the working fluid. With the present research and development programmes, the MHD power generation may play an important role in the power industry in future to help the present crisis of power.
The MHD process can be used not only for commercial power generation but also for so may other applications.The economic attractiveness of MHD for bulk generation of power from fossil fuel has been indicated in many design studies and cost estimates of conceptual plants. MHD promises a dramatic improvement in the cost of generating electricity from coal, beneficial to the growth of the national economy. The extensive use of MHD can help in saving billions of dollars towards fuel prospects of much better fuel utilization are most important, but the potential of lower capital costs with increased utilization of invested capital provides also a very important economic incentive. The beneficial environmental aspects of MHD are probably of equal or even greater significance. The MHD energy conversion process cab contribute greatly to the solution of the serious air and thermal pollution problems faced by all steam - electric power plants while it simultaneously assures better utilization for our natural resources. It can therefore be claimed that the development of MHD for electric utility power generation is an objective of national significance. The high temperature MHD process makes it possible to take advantage of the highest flame temperatures which can be produced by combustion from fossil fuel. While commercial nuclear reactors able to provide heat for MHD have yet to be developed, the combined use to MHD with nuclear heat source holds great promise for the future.In India, coal is by far the most abundant fossil fuel and thus the major energy source for fossil fueled MHD power generation. Before large central station power plants with coal as the energy source can be become commercially viable, further development is necessary..