Geothermal energy potential in relation to black carbon reduction and CO₂ mitigation of Himalayan geothermal belt - A review

We have compiled geochemical dataset of springs (Thermal and Cold) from the Himalayan Geothermal Belt (HGB), shows slightly acidic to moderately alkaline (pH = 4.5 - 9.4) in nature with an emerging surface temperature of 27 degrees C - 96 degrees C. The calculated reservoir temperature ranged in between 78 degrees C - 159 degrees C categorize the HGB as a low- to a moderate-enthalpy geothermal system. It was observed that geochemical facies of thermal springs dominated by the Ca-HCO3, Na-HCO3 and Na-Cl composition while cold springs are abundant in Ca-Mg-HCO3 and Ca-Mg-SO4. Interestingly, Piper diagram inferred that Puga, Chumathang, and Gaik thermal springs, lies in the western part of HGB that correlate with the Yangbajing thermal spring in Tibet (eastern part of HGB). Tectonically, the HGB is associated with the continental collision zone, shallow crustal melting, and high heat-producing younger granite (70 mW/m(2) to > 400 mW/m(2)); therefore, the resultant geothermal gradient along the HGB is more than 200 degrees C/km. The present research documents that HGB have potential to reduce CO2 and BC emissions by taping the geothermal energy for power generation and we have projected that the power potential of HGB is 23,622 MWe that can help to mitigate 1.4 x 10(8) tCO(2).