Comparative techno-economic assessment of superhot rock and conventional geothermal energy feasibility for decarbonizing India

The commercial viability of low-temperature geothermal basins is still a major stumbling block for field implementation of geothermal projects in India. Though there are several low-temperature basins, the presence of high-temperature gradient in few regions of India led to the hypothesis of testing the advanced geothermal potential in India. Therefore, this study holistically investigates the prospect of superhot rock geothermal potential in India vis-à-vis the techno-economical prospect and reservoir characteristics. Additionally, a comparative study is conducted with respect to the conventional geothermal system in the Son-Narmada-Tapti field to understand the effects of technical and economic parameters.

The geothermal provinces in India can be utilized to reduce the use of fossil fuels for direct use and heating applications. However, geothermal resources suffer a setback due to high capital cost and risks associated with the feasibility of extraction process of heat energy. This study investigates the possibility of a superhot rock site to drive down the cost. To assess the technical feasibility, a comprehensive study is conducted using the reservoir heat and flow simulation for the proposed site. The study is conducted using the commercial package to obtain the heat energy that can be generated over the thirty years of injection and production. The feasibility analysis cannot be complete without the study of economic aspects. Hence, the market cost of electricity (LCOE) is estimated to understand the economic feasibility of the proposed superhot rock project. To get a better insight into the superhot rock potential, the resource potential and economic feasibility is compared with the similar system for the conventional geothermal prospect.

The reservoir simulation study suggests that the dual superhot rock well system has capacity to provide 170 – 175 MWe in the region which is much higher than that of the conventional system (12 – 15 MWe). Also, it was observed that the dual well geothermal system, the waterfront does not reach the producer well over the thirty years of cold-water injection in both systems. The economic feasibility study shows that the levelized cost of electricity is most likely to be $67/MWh which is significantly less than the conventional geothermal system ($122/MWh).