Unconventional Technologies for Sustainable Coal Energy in India

Coal is a fossil fuel and majorly satisfies our energy need. Although coal resources are depleting, it is still to be a sustainable energy source for future in terms of unutilized sources. As per the survey of “Statistical review of world energy,” India stands third position in coal production after China and the USA in the year 2015 with an increase in the growth rate of 4.7% over the last year. According to the current Geological Survey of India 2016, approximately 308.8 billion tons of coal reserves are available in India up to a depth of 1200 m. In India, 70% of the electricity production and 60% of the commercial energy production depend on coal resources. Out of the total coal reserves in India, approximately 39.4% (~121.65 billion tons) of coal lies under a depth more than 300–1200 m, which is out of human reach for exploitation in an economical way by conventional method. To match the current energy demand, there are few other alternative technologies such as underground coal gasification (UCG) and coal bed methane (CBM) to utilize deep coal seams economically. Underground coal gasification (UCG) is a method of converting coal in situ into syngas, which can be used for electricity generation and synthesis of chemicals and liquid fuels. Another energy source from coal is high calorific value CBM gas, which contains 95–98% pure methane. CBM gas formed during the coalification process gets evolved during coal mining process. Capturing this methane gas prior to mining or from unutilized deep coal seams would be a sustainable energy for future demand. In this chapter, we will discuss the estimate of available energy resources and its exploitation through these unconventional technologies for sustainable energy production in India.