Hydro power[edit]

Main article: Hydroelectric power in India

Indira Sagar Dam partially completed in 2008

Nagarjuna Sagar Dam and the 810 MW hydroelectric power plant on the Krishna River.

The hydro-electric power plants at Darjeeling and Shivanasamudram were established in 1898 and 1902 respectively and were among the first in Asia.
India is endowed with economically exploitable and viable hydro potential assessed to be about 84,000 MW at 60% load factor. In addition, 6740 MW in terms of installed capacity from Small, Mini, and Micro Hydro schemes have been assessed. Also, 56 sites for pumped storage schemes with an aggregate installed capacity of 94,000 MW have been identified. It is the most widely used form of renewable energy. India is blessed with immense amount of hydro-electric potential and ranks 5th in terms of exploitable hydro-potential on global scenario.
The present installed capacity as of 31 May 2014 is approximately 40,661.41 MW which is 16.36% of total electricity generation in India.^[91] The public sector has a predominant share of 97% in this sector.^[92] National Hydroelectric Power Corporation (NHPC), Northeast Electric Power Company (NEEPCO), Satluj jal vidyut nigam (SJVNL), Tehri Hydro Development Corporation, NTPC-Hydro are a few public sector companies engaged in development of hydroelectric power in India.
Pumped storage schemes are perfect centralised peaking power stations for the load management in the electricity grid. Pumped storage schemes would be in high demand for meeting peak load demand and storing the surplus electricity as India graduates from electricity deficit to electricity surplus. They also produce secondary /seasonal power at no additional cost when rivers are flooding with excess water. Storing electricity by other alternative systems such as batteries, compressed air storage systems, etc. is more costlier than electricity production by standby generator. India has already established nearly 6800 MW pumped storage capacity which is part of its installed hydro power plants.^[93]

Solar power[edit]

Main article: Solar power in India

Price history of silicon PV cells (not modules) since 1977. The great thing about solar power is that it is a technology and not a fuel. It is unlimited and the more it is deployed the cheaper it would be.^[94] While the more limited fossil fuels are used, the more expensive they become.

India is endowed with vast solar energy. The solar radiation of about 5,000 trillion kWh per year is incident over its land mass with average daily solar power potential of 0.25 kWh per m² of used land area with the available commercially proven technologies.^[95] As of 31 August 2016, the installed capacity was 8.1 GW. Solar installations in India is expected to reach 4.8 GW in 2016 with a 21 GW development pipeline.
Installation of solar power plants require nearly 2.4 hectares (0.024 km²) land per MW capacity which is similar to coal-fired power plants when life cycle coal mining, consumptive water storage & ash disposal areas are also accounted and hydro power plants when submergence area of water reservoir is also accounted. 1.33 million MW capacity solar plants can be installed in India on its 1% land (32,000 square km). There are vast tracts of land suitable for solar power in all parts of India exceeding 8% of its total area which are unproductive barren and devoid of vegetation.^[96] Part of waste lands (32,000 square km) when installed with solar power plants can produce 2,000 billion Kwh of electricity (two times the total generation in the year 2013-14) with land annual productivity/yield of ₹1.0 million (US$15,000) per acre (at 4 Rs/kwh price) which is at par with many industrial areas and many times more than the best productive irrigated agriculture lands.^[97] Moreover, these solar power units are not dependent on supply of any raw material and are self productive. There is unlimited scope for solar electricity to replace all fossil fuel energy requirements (natural gas, coal, lignite, nuclear fuels and crude oil) if all the marginally productive lands are occupied by solar power plants in future. The solar power potential of India can meet perennially to cater per capita energy consumption at par with USA/Japan for the peak population in its demographic transition.^[98]
In the year 2016, the levelized tariff in US$ for solar electricity has fallen below 3 cents/kWh which is far cheaper than the fuel cost incurred by coal based power plants in India.^[99][100]

Canal Solar Power Project in Kadi, Gujarat

Land acquisition is a challenge to solar farm projects in India. Some state governments are exploring means to address land availability through innovation; for example, by exploring means to deploy solar capacity above their extensive irrigation canal projects, thereby harvesting solar energy while reducing the loss of irrigation water by solar evaporation.^[101] The state of Gujarat was first to implement the Canal Solar Power Project, to use 19,000 km (12,000 mi) long network of Narmada canals across the state for setting up solar panels to generate electricity. It was the first ever such project in India.
Synergy with irrigation water pumping and hydro power stations
The major disadvantage of solar power (PV type) is that it can not produce electricity during the nighttime and cloudy daytime also. In India, this disadvantage can be overcome by installing pumped-storage hydroelectricity stations. Ultimate electricity requirement for river water pumping (excluding ground water pumping) is 570 billion Kwh to pump one cubic meter of water for each square meter area by 125 m height on average for irrigating 140 million hectares of net sown area (42% of total land) for three crops in a year.^[102] This is achieved by utilising all the usable river waters by interlinking Indian rivers.^[103] These river water pumping stations would also be envisaged with pumped-storage hydroelectricity features to generate electricity during the night time. These pumped-storage stations would work at 200% water pumping requirement during the daytime and generate electricity at 50% of total capacity during the nighttime. Also, all existing and future hydro power stations can be expanded with additional pumped-storage hydroelectricity units to cater night time electricity consumption. Most of the ground water pumping power can be met directly by solar power.^[104]

Wind power[edit]

Main article: Wind power in India

Wind farm in Rajasthan.

Wind turbines midst India's agricultural farms.

Wind farms midst paddy fields in India.

India has the fifth largest installed wind power capacity in the world. In the year 2015-16, wind power accounted for 8.5% of India's total installed power capacity, and 2.5% of the country's power output. India targets to install an additional 60 GW of wind power capacity by 2022^[105]
The development of wind power in India began in the 1990s by Tamil Nadu Electric Board near Tuticorin, and has significantly increased in the last decade. As of 31 March 2016, the installed capacity of wind power was 26.74 GW, spread across many states of India.^[88] The largest wind power generating state is Tamil Nadu accounting for nearly 30% of installed capacity, followed in decreasing order by Maharashtra, Gujarat, Rajasthan and Karnataka.^[106]

Biomass power[edit]

Biomass is organic matter derived from living, or recently living organisms. As an energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel. Conversion of biomass to biofuel can be achieved by different methods which are broadly classified into: thermal, chemical, and biochemical methods.^[107] In this system biomass, bagasse, forestry, domestic organic wastes, industrial organic wastes and agro residue & agricultural wastes are used as fuel to produce electricity.^[108] Nearly 750 million tons of non edible (by cattle) biomass is available annually in India which can be put to use for higher value addition.^[109] Biomass is a renewable energy source as it is generated by extracting the carbon dioxide gas from the atmosphere. Its use for electricity generation is carbon-neutral fuel because it would also release global warming green house gasses like methane and carbon dioxide when it is left to decay / degenerate without using as an energy source. The total biomass traditional use in India is nearly 177 Mtoe in the year 2013.^[110]
Two thirds of house holds in India use biomass and charcoal for cooking purpose. As traditional use of biomass is being replaced by LPG in rural areas at faster pace, biomass burning in agriculture fields would become major source for causing higher level air pollution.^{[citation needed]} According to the International Energy Agency‌, 819 million Indians, or 63% of the total population, rely on traditional uses of biomass.^[111]

Torrefied biomass

Huge quantity of imported coal is being used in pulverised coal-fired power stations. Raw biomass is not suitable for use in the pulverised coal mills as they are difficult to grind into fine powder due to its caking problem. However 100% biomass can be fired after Torrefaction in the pulverised coal mills for replacing imported coal.^[112] Torrefied biomass plants can be integrated with existing pulverised coal-fired power stations using the available hot flue gas as heat source. Cofiring dry biomass up to 20% heat input with coal is possible directly in pulverised coal-fired power stations without facing caking problem.^[113] North west and southern regions can replace imported coal use with biomass where surplus agriculture/crop residue biomass is burnt in the fields causing pollution problems.

Biomass gasifier

India has been promoting biomass gasifier technologies in its rural areas, to utilise surplus biomass resources such as rice husk, crop stalks, small wood chips, other agro-residues. The goal was to produce electricity for villages with power plants of up to 2 MW capacities. During 2011, India installed 25 rice husk based gasifier systems for distributed power generation in 70 remote villages of Bihar. The largest biomass-based power plant in India is at Sirohi, Rajasthan, having the capacity of 20 MW, i.e., Sambhav Energy Limited. In addition, gasifier systems are being installed at 60 rice mills in India. During the year, biomass gasifier projects of 1.20 MW in Gujarat and 0.5 MW in Tamil Nadu were successfully installed.^[90]

Biogas

This pilot programme aims to install small-scale biogas plants for meeting the cooking energy needs in rural areas of India. During 2011, some 45000 small-scale biogas plants were installed. Cumulatively, India has installed 4.44 million small-scale biogas plants.
In 2011, India started a new initiative with the aim to demonstrate medium size mixed feed biogas-fertiliser pilot plants. This technology aims for generation, purification/enrichment, bottling and piped distribution of biogas. India approved 21 of these projects with aggregate capacity of 37016 cubic metre per day, of which 2 projects have been successfully commissioned by December 2011.^[90]
India has additionally commissioned 158 projects under its Biogas based Distributed/Grid Power Generation programme, with a total installed capacity of about 2 MW.
India is rich in biomass and has a potential of 16,881 MW (agro-residues and plantations), 5000 MW (bagasse cogeneration) and 2700 MW (energy recovery from waste). Biomass power generation in India is an industry that attracts investments of over INR 6 billion every year, generating more than 5000 million units of electricity and yearly employment of more than 10 million man-days in the rural areas.^{[citation needed]}
As of 2010, India burnt over 200 million tonnes of coal replacement worth of traditional biomass fuel every year to meet its energy need for cooking and other domestic use. This traditional biomass fuel – fuelwood, crop waste and animal dung – is a potential raw material for the application of biomass technologies for the recovery of cleaner fuel, fertilisers and electricity with significantly lower pollution.
Biomass available in India can and has been playing an important role as fuel for sugar mills, textiles, paper mills, and small and medium enterprises (SME). In particular there is a significant potential in breweries, textile mills, fertiliser plants, the paper and pulp industry, solvent extraction units, rice mills, petrochemical plants and other industries to harness biomass power.^[114]

Geothermal energy[edit]

Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. India's geothermal energy installed capacity is experimental. Commercial use is insignificant.
According to some ambitious estimates, India has 10,600 MW of potential in the geothermal provinces but it still needs to be exploited.^[115] India has potential resources to harvest geothermal energy. The resource map for India has been grouped into six geothermal provinces:^[116]

• Himalayan Province – Tertiary Orogenic belt with Tertiary magmatism
• Areas of Faulted blocks – Aravalli belt, Naga-Lushi, West coast regions and Son-Narmada lineament.
• Volcanic arc – Andaman and Nicobar arc.
• Deep sedimentary basin of Tertiary age such as Cambay basin in Gujarat.
• Radioactive Province – Surajkund, Hazaribagh, Jharkhand.
• Cratonic province – Peninsular India

India has about 340 hot springs spread over the country. Of this, 62 are distributed along the northwest Himalaya, in the States of Jammu and Kashmir, Himachal Pradesh and Uttarakhand. They are found concentrated along a 30-50-km wide thermal band mostly along the river valleys. Naga-Lusai and West Coast Provinces manifest a series of thermal springs. Andaman and Nicobar arc is the only place in India where volcanic activity, a continuation of the Indonesian geothermal fields, and can be good potential sites for geothermal energy. Cambay graben geothermal belt is 200 km long and 50 km wide with Tertiary sediments. Thermal springs have been reported from the belt although they are not of very high temperature and discharge. During oil and gas drilling in this area, in recent times, high subsurface temperature and thermal fluid have been reported in deep drill wells in depth ranges of 1.7 to 1.9 km. Steam blowout have also been reported in the drill holes in depth range of 1.5 to 3.4 km. The thermal springs in India's peninsular region are more related to the faults, which allow down circulation of meteoric water to considerable depths. The circulating water acquires heat from the normal thermal gradient in the area, and depending upon local condition, emerges out at suitable localities. The area includes Aravalli range, Son-Narmada-Tapti lineament, Godavari and Mahanadi valleys and South Cratonic Belts.^[116]
In a December 2011 report, India identified six most promising geothermal sites for the development of geothermal energy. These are, in decreasing order of potential:

• Tattapani in Chhattisgarh
• Puga in Jammu & Kashmir
• Cambay Graben in Gujarat
• Manikaran in Himachal Pradesh
• Surajkund in Jharkhand
• Chhumathang in Jammu & Kashmir

India plans to set up its first geothermal power plant, with 2–5 MW capacity at Puga in Jammu and Kashmir.^[117]

Tidal power[edit]

Tidal power, also called tidal energy, is a form of hydropower that converts the energy obtained from tides into useful forms of power, mainly electricity. The potential of tidal wave energy becomes higher in certain regions by local effects such as shelving, funnelling, reflection and resonance.
India is surrounded by sea on three sides, its potential to harness tidal energy is significant. Energy can be extracted from tides in several ways. In one method, a reservoir is created behind a barrage and then tidal waters pass through turbines in the barrage to generate electricity. This method requires mean tidal differences greater than 4 metres and also favourable topographical conditions to keep installation costs low. One report claims the most attractive locations in India, for the barrage technology, are the Gulf of Khambhat and the Gulf of Kutch on India's west coast where the maximum tidal range is 11 m and 8 m with average tidal range of 6.77 m and 5.23 m respectively. The Ganges Delta in the Sunderbans, West Bengal is another possibility, although with significantly less recoverable energy; the maximum tidal range in Sunderbans is approximately 5 m with an average tidal range of 2.97 m. The report claims, barrage technology could harvest about 8 GW from tidal energy in India, mostly in Gujarat. The barrage approach has several disadvantages, one being the effect of any badly engineered barrage on the migratory fishes, marine ecosystem and aquatic life. Integrated barrage technology plants can be expensive to build.
In December 2011, the Ministry of New & Renewable Energy, Government of India and the Renewable Energy Development Agency of Govt. of West Bengal jointly approved and agreed to implement India's first 3.75 MW Durgaduani mini tidal power project. Indian government believes that tidal energy may be an attractive solution to meet the local energy demands of this remote delta region.^[117]
Another tidal wave technology harvests energy from surface waves or from pressure fluctuations below the sea surface. A report from the Ocean Engineering Centre, Indian Institute of Technology, Madras estimates the annual wave energy potential along the Indian coast is between 5 MW to 15 MW per metre, suggesting a theoretical maximum potential for electricity harvesting from India's 7500 kilometre coast line may be about 40 GW. However, the realistic economical potential, the report claims, is likely to be considerably less.^[118] A significant barrier to surface energy harvesting is the interference of its equipment to fishing and other sea bound vessels, particularly in unsettled weather. India built its first seas surface energy harvesting technology demonstration plant in Vizhinjam, near Thiruruvananthpuram.
The third approach to harvesting tidal energy consists of ocean thermal energy technology. This approach tries to harvest the solar energy trapped in ocean waters into usable energy. Oceans have a thermal gradient, the surface being much warmer than deeper levels of ocean. This thermal gradient may be harvested using modified Rankine cycle. India's National Institute of Ocean Technology (NIOT) attempted this approach over the last 20 years, but without success. In 2003, with Saga University of Japan, NIOT attempted to build and deploy a 1 MW demonstration plant.^[119] However, mechanical problems prevented success. After initial tests near Kerala, the unit was scheduled for redeployment and further development in the Lakshadweep Islands in 2005. The demonstration project's experience have limited follow-on efforts with ocean thermal energy technology in India.

Nuclear power[edit]

Main article: Nuclear power in India

Kudankulam Nuclear Power Plant (2 x 1000 MW) under construction in 2009.

As of Apr 30, 2016, India had 5.78 GW of installed nuclear electricity generation capacity^[86] or 1.91% of total installed electricity generation capacity in India. India's Nuclear plants generated 37,835 million units in year 2014-15.^[120]
India's nuclear power plant development began in 1964. India signed an agreement with General Electric of the United States for the construction and commissioning of two boiling water reactors at Tarapur. In 1967, this effort was placed under India's Department of Atomic Energy. In 1971, India set up its first pressurized heavy water reactors with Canadian collaboration in Rajasthan. In 1987, India created Nuclear Power Corporation of India Limited to commercialize nuclear power.
Nuclear Power Corporation of India Limited is a public sector enterprise, wholly owned by the Government of India, under the administrative control of its Department of Atomic Energy. Its objective is to implement and operate nuclear power stations for India's electricity sector. The state-owned company has ambitious plans to establish 63 GW generation capacity by 2032, as a safe, environmentally benign and economically viable source of electrical energy to meet the increasing electricity needs of India.^[121]
India's nuclear power generation effort satisfies many safeguards and oversights, such as getting ISO-14001 accreditation for environment management system and peer review by World Association of Nuclear Operators including a pre-start up peer review. Nuclear Power Corporation of India Limited admits, in its annual report for 2011, that its biggest challenge is to address the public and policy maker perceptions about the safety of nuclear power, particularly after the Fukushima incident in Japan.^[120]
In 2011, India had 18 pressurized heavy water reactors in operation, with another four projects of 2.8 GW capacity launched. The country plans to implement fast breeder reactors, using plutonium based fuel. Plutonium is obtained by reprocessing spent fuel of first stage reactors. India is in the process of launching its first prototype fast breeder reactor of 500 MW capacity in Tamil Nadu.
India has nuclear power plants operating in the following states: Maharashtra, Gujarat, Rajasthan, Uttar Pradesh, Tamil Nadu and Karnataka. These reactors have an installed electricity generation capacity between 100 MW and 540 MW each. KKNPP Unit-1 with a capacity of 1,000 MWe was commissioned in July, 2013 while KKNPP Unit-2, also with a capacity of 1,000 MWe is nearing first approach to criticality in 2016.
In 2011, The Wall Street Journal reported the discovery of uranium in a new mine in India, the country's largest ever. The estimated reserves of 64,000 tonnes, could be as large as 150,000 tonnes (making the mine one of the world's largest). The new mine is expected to provide India with a fuel that it now imports. Nuclear fuel supply constraints had limited India's ability to grow its nuclear power generation capacity. The newly discovered ore, unlike those in Australia, is of slightly lower grade. This mine is expected to be in operation in 2012.^[122]
India's share of nuclear power plant generation capacity is just 1.2% of worldwide nuclear power production capacity, making it the 15th largest nuclear power producer. India aims to supply 9% of it electricity needs with nuclear power by 2032.^[120] India's largest nuclear power plant project is planned to be implementedat Jaitapur, Maharashtra in partnership with Areva, France.
India's government is also developing up to 62, mostly thorium reactors, which it expects to be operational by 2025. It is the "only country in the world with a detailed, funded, government-approved plan" to focus on thorium-based nuclear power. The country currently gets under 2% of its electricity from nuclear power, with the rest coming from coal (60%), hydroelectricity (16%), other renewable sources (12%) and natural gas (9%). It expects to produce around 25% of its electricity from nuclear power.^[123]