a) Binary cycle power plantThedifference between this and the first two technologies is that, the water orsteam which is taken from the hot reservoir which is located underneath thesurface of the earth does not come into contact with the turbine 3. Insteadthis water or steam is used to heat up a secondary liquid in a secondary pipeand this liquid has a much lower boiling point than water (as low as 14°C) 3.The vapor from this liquid move upwards and passes through the turbine and thepressure of this vapor is used to rotate the turbines 3.
Once the turbine isrotated, the vapor is sent to a condensing chamber where cold water (of about19°C) is used to cool down this vapor back to its liquid form and is collectedat the bottom of the tank and the water leaves at a temperature of about 30°C3. This liquid flows down the outlet of the tank to the pump where it isre-pressurized and sent back into the exchanger for re-use 3. The water whichwas used in the process is sent to the cooling tower where it is cooled from 30°Cto 19°C 3. Figure 4 shows a binary cycle power plant.Thisreport primarily focuses on the feasibility of geothermal energy in India andhow it can provide significant amount of new energy to the energy system in thenext three decades which results in the reduction in carbon emissions.1) Energy Background in IndiaIndiais the third largest consumer of electricity.
The total installed capacity is333.11 GW 4 and the breakdown by source is as follows:· Coal – 58.5% 7· Renewables – 31.8% 7Ø Hydro– 14.8% 7Ø Wind– 9.9% 7Ø Solar– 4.
5% 7Ø Biomass– 2.5% 7· Nuclear – 2% 7· Gas – 7.6% 7· Diesel – 0.3% 7In2016, the coil consumption in India increased by 8.3% to 212.7 million tonnescompared to the 1.
5% in global increase, resulting in India being the thirdlargest consumer of oil in the world 8. Between the years of 2005 and 2015,the consumption rate increased by 4.9% in India while for the rest of theworld, it increased by 1% 8. India is the fourth largest producer of carbondioxide accounting for 6.81% of the total world emissions. In2015, the GHG emissions due to electricity production was about 2066.
01 MtCO29. For the next few decades, the use of coal and oil will continue todominate the energy sector. However emissions need to be reduced by increasingthe use of green energy/non-conventional energy sources. Currently hydro, solarand wind contribute about 29.3% of the total installed capacity 10. 30% ofthe total electricity consumption comes from residential and commercialbuilding sectors and 55% of this electricity consumption is due to HVAC 10. Morethan 65% of electricity consumption of a commercial or industrial building isdue to air-conditioning and process cooling/heating resulting in large amountof CO2 10. This can be reduced with the use of heating/coolingsystems that use geothermal energy.
The Ministry of New & Renewable Energy(MNRE) has proposed a policy in order to implement geothermal energy and someof the findings have been used in this report 10.Figure5 shows India’s projected electricity production by 20202.1) Vision and Goal of the MNREAccordingto the Geothermal Energy Development Framework, the vision is to create along-term energy supply of geothermal energy in order to reduce GHG emissionsby creating a geothermal industry that is sustainable, safe, secure, sociallyand environmentally friendly and at the same time help in creating newprospects of employment 10. The goal is to reach 1000 MW (thermal) and 20 MW(electrical) Geothermal Energy Capacity by 2022 and 10,000 MW (thermal) and1000 MW (electrical) by 2030 by collaborating with countries such as US, Philippines,Mexico and New Zealand 10. 2.
2) Geothermal Energy in IndiaIndiahas great potential of becoming a leading contributor in the generation ofeco-friendly and cost effective geothermal power 1. But one of the reasonsfor not building up geothermal power projects is due to high availability ofcoal as well as its low cost 11. However due to increasing emissions, Indianeeds to start going in the direction of alternative sources and geothermallooks to be a good way to substitute some of the coal and oil used to produceelectricity. According to the Geothermal Energy Development Framework, the growthof geothermal energy needs deeper excavation and use of energy for theproduction of electricity 10.
This was held up due to the lack of machineryand equipment needed for deep drilling 10. Only thirty one areas have beenanalyzed in detail and shallow drilling of up to a maximum depth of 728m incertain areas and less in others 10. So far bathing, swimming, balneology andin certain cases a source for cooking have been the direct-uses of geothermalenergy in the country. The annual geothermal use for these activities hasincreased from 2545 TJ in 2010 to 4152TJ in 2014 and the installed capacity is981 MWt 10. 2.3) History of Geothermal Studies in IndiaAccordingto the Geothermal Energy Development Framework, the Geological Survey of India(GSI) has performed a preliminary analysis and has showed the prospects ofdeveloping geothermal power 10. The exploration of geothermal resourcesstarted in 1973 and the preliminary analysis shows that India is in a low andmedium heat enthalpy region (100-180°C) 10.
Around 340 hot springs have beenfound is different regions of India with a surface temperature ranging between 35°Cand 98°C 10. Currentlythe geothermal resources are in its nascent stages mainly due to the abundanceof coal and its cheap price 10. However due to the increasing emissions,India needs to implementing more renewable sources of energy apart of hydro,wind and solar and geothermal looks to be one of those sources 10.2.
4) Geothermal Resources in IndiaThereare 2 enthalpy geothermal system in India as follows:a) MediumEnthalpy (100°C-200°C)Thisregion is associated with:· The geothermal fields of Puga-Chumathang,Parbati, Beas and Satluj Valley as these regions have younger intrusivegranites 10.· West coast areas of Maharashtra; along theSon-Narmada-Tapi lineament belt at Salbardi, Tapi; Satpura areas inMaharashtra; Tattapani in Chhattisgarh and Rajgir-Monghyar in Bihar, Tatta andJarom in Jharkhand and Eastern Ghat tracts of Orissa 10.· Rift and grabens of Gondwana basins ofDamodar, Godavari and Mahanadi Valleys 10.· Quaternary and tertiary deposits found ina graben in the Cambay basin of the West Coast 10.b) LowEnthalpy (<100°C)Thisregion is associated with:· Tertiary tectonism and neotectonicactivity 10.· Shield areas with localized abnormal heatflow, which is normally very low 10.Figure6 shows 7 geothermal provinces in India.
Figure6 – 7 Geothermal Provinces 12India is divided intoorogenic and non-orogenic geothermal regions. The orogenic regions are asfollows:· Himalayan Region – NorthwestØ PugaRegiono This region is about 180km from Leh inLadakh Region of Jammu and Kashmir across the Great Himalayan range at analtitude of 4400m above mean sea level (amsl) 13. The thermal phenomenon ofthis region appear in the form of hot springs, hot pools, sulphur condensates,borax evaporates that have an aerial extent of 4km 13. Figure 7a) shows a hotspring geyser at Puga and Figure 7b) shows the sulphur deposits at Puga 13.
The hotsprings have a temperature of about 30°C to 84°C and the maximum discharge ratefrom a single spring is 5litres/sec 13.o Geophysical surveys indicate that thesouthwest part of the Puga geothermal region has a really low resistivity zoneof about 2-10 ?m indicating the occurrence of thermal-water in the sub-surface 13.o The water in this region has a ph levelbetween 6 and 8.3 and is mainly of NAHCO3Cl type 13.
Geochemicalthermometers indicate (based on the concentration of Na,K,Ca and Mg) the chanceof having thermal liquids with temperatures between 220°C-260°C 13. Thetemperature gradient is high between 0.35 to 2.5°C/m and some places have agradient of about 6.8°C/m 13.o 34 boreholes with depths ranging between28.5m and 384.
7m have been dug in this region 13. The boreholes that havestruck steam-water have generated 10-15% steam with a temperature of 140°C 13.Wellhead measurements was taken for 8 boreholes and the total discharge forthese 8 boreholes was found to be 190 tones/hour consisting of steam/water 13.The maximum discharge of a single drill hole was found to be 30 tones/hour 13.
o Using the geothermal fluids in thisregion, space heating for a 5m*5m*2.5m hut was successful heated to atemperature greater than 20°C and maintained. Borax and sulphur refinement wasalso able to be done 13. o Currently, this region is the only capableregion of producing either primary cycle electrical power or binary power butreservoir simulation studies indicates that a power of 3 MW can be generated ifdeeper levels are investigated up to at least 500m 13. Ø ChhumathangRegion:o This region is located 40km north of Puga.Magnetic, seismic refraction and resistivity assessments have been done in thisregions 13. The assessment indicates that region has low resistivity of about13-30 ?m up to a depth of 300m 13.
o The thermal manifestations appear in theform of a carbonate plateau with a diameter of about 100m and height of about6-10m as shown in Figure 8 13.