- Hydraulic power can be captured when water flows downward from a higher level to a lower level which is then used to turn the turbine, thereby converting the kinetic of water into mechanical energy to drive the generator.
- The energy produced is directed to a substation, where transformers “step up” the voltage before its transmission to the electricity grid.
- Hydropower is the cheapest and cleanest source of energy but there are many environmental and social issues associated with big dams as seen in projects like Tehri, Narmada, etc. small hydropower is free from these problems.
- India has 197 Hydro Power plants. The end of the 19th century saw the development of power in India. In 1897, electricity was commissioned in Darjeeling and in 1902, a Hydro Power station at Sivasamudram in Karnataka was commissioned.
Types of hydro power stations
There are three types of hydropower facilities: impoundments, diversion, and pumped storage some hydropower plants use dams and some do not.
- Impoundment: The most common type of hydroelectric power plant is an impoundment facility. An impoundment facility, typically a large hydropower system, uses a dam to store river water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity.
- Diversion: A diversion, sometimes called a run-of-river facility, channels a portion of a river through a canal or penstock and then flows through a turbine, spinning it, which in turn activates a generator to produce electricity. It may not require the use of a dam.
- Pumped storage: It works like a battery, storing the electricity generated by other power sources like solar, wind, and nuclear for later use. When the demand for electricity is low, a pumped storage facility stores energy by pumping water from a lower reservoir to an upper reservoir. During periods of high electrical demand, the water is released back to the lower reservoir and turns into a turbine, generating electricity.
Classification of Hydro Projects based on Installed Capacity
Hydro power projects are generally categorized in two segments i.e. small and large hydro. In India, hydro projects up to 25 MW station capacities have been categorized as Small Hydro Power (SHP) projects.
- Micro: upto 100 KW
- Mini: 101KW to 2 MW
- Small: 2 MW to 25 MW
- Mega: Hydro projects with installed capacity >= 500 MW
- Thermal Projects with installed capacity >=1500 MW
While Ministry of Power, Government of India is responsible for large hydro projects, the mandate for the subject small hydro power (up to 25 MW) is given to Ministry of New and Renewable Energy.
Small hydro power (SHP)
- Small hydro is defined as any hydropower project which has an installed capacity of less than 25 MW. It is in most cases run-of-river, where a dam or barrage is quite small, usually, just a weir with little or no water is stored. Therefore run-of-river installations do not have the same kind of adverse effect on the local environment as large-scale hydro projects. Small hydropower plants can serve the energy needs of remote rural areas independently.
- India and China are the major players of the SHP sector, holding the highest number of installed projects.
Advantages of hydropower
- Hydropower is a renewable source of energy because it uses and not consumes the water for generation of electricity, and the hydropower leaves this vital resource available for other uses.
- It is a renewable source of energy with no consumables involved; there is very little recurring cost and hence no high long term expenditure.
- It is cheaper as compared to electricity generated from coal and gas fired plants. It also reduces the financial losses due to frequency fluctuations and it is more reliable as it is inflation free due to not usage of fossil fuel.
- Hydropower stations are preferred solution for meeting peak loads in grids due to its unique capabilities of quick starting and closing.
- The operational needs of hydro & thermal stations are complimentary and the balanced mix helps in optimal utilization of the capacity.
- Seasonal load curves of regional grids match with the pattern of hydro power generation. During summer/monsoon season when the generation at hydro power plants is high, the load factor of the system is high due to heavy agricultural load. During winter, the thermal stations operating at base load and hydro stations working as peak load stations will take care of weather beating loads.
Disadvantages of Hydroelectric power
- The hydropower generation is highly capital-intensive mode of electricity generation.
- Due to the fact that hydropower projects are primarily located in hilly areas, where forest cover is comparatively better than plain areas, diversion of forest land is sometimes unavoidable.
- Submergence of land, thereby loss of flora and fauna and large scale displacement, due to the hydropower projects.
- Dams can only be built at specific locations.
- A Large area of agriculture is submerged underwater.
Hydropower Scenario in India
- India is 5th globally for installed hydroelectric power capacity.
- As of 31 March 2020, India’s installed utility-scale hydroelectric capacity was 46,000 MW or 12.3% of its total utility power generation capacity.
(i) Additional smaller hydroelectric power units with a total capacity of 4,683 MW (1.3% of its total utility power generation capacity) have been installed.
(ii) India’s hydroelectric power potential is estimated at 148,700 MW at a 60% load factor. An additional 6,780 MW from smaller hydro schemes (with capacities of less than 25 MW) is estimated as exploitable.
(iii) In the fiscal year 2019–20, the total hydroelectric power generated in India was 156 TWh (excluding small hydro) with an average capacity factor of 38.71%.
- Hydropower potential is located mainly in northern and north-eastern regions.
- Arunachal Pradesh has the largest unexploited hydropower potential of 47 GW, followed by Uttarakhand with 12 GW.
- Unexploited potential is mainly along three river systems – the Indus, Ganges and Brahmaputra.
- India has over 90 GW of pumped storage potential, with 63 sites identified and recognised in national energy policies for their valuable grid services.
- India has an estimated hydropower potential of 1,45,320 MW, excluding small hydro projects (SHPs) which has 20 GW potential.
- The estimated potential of Small Hydropwer of 21135.37 MW from 7135 sites for power generation in the country from small/mini hydel projects is assessed by the Alternate Hydro Energy Centre (AHEC) of IIT Roorkee in its Small Hydro Database of July 2016.
- The hilly States of India mainly Arunachal Pradesh, Himachal Pradesh, Jammu & Kashmir and Uttarakhand, and constitute around half of this potential. Other potential States are Maharashtra, Chhattisgarh, Karnataka and Kerala.
- India also imports surplus hydroelectric power from Bhutan.
- The public sector accounts for 92.5% of India’s hydroelectric power production. The private sector is also expected to grow with the development of hydroelectric energy in the Himalayan mountain ranges and in the northeast of India.
- Load factor is an expression of how much energy was used in a time period, versus how much energy would have been used, if the power had been left on during a period of peak demand.
Issues in Hydropower generation
- In central India, the hydroelectric power potential from the Godavari, Mahanadi, Nagavali, Vamsadhara and Narmada river basins has not been developed on a major scale due to potential opposition from the tribal population.
- Hydropower’s share in the electricity mix has, however, been decreasing over the years, accounting for around 10 per cent of generation, with the majority (80 per cent) coming from thermal generation.
- Many current hydropower projects have been slow going with delays due to complex planning procedures, prolonged land acquisition and resettlement, a lack of enabling infrastructure including transmission, insufficient market scope and long-term financing.
- Several hydroelectric projects (HEPs) in India are languishing due to contractual conflicts, environmental litigations, local disturbances, financial stress and unwilling purchasers.
- Only about 10,000 MW of hydropower could be added over the last 10 years.
- As water and water power are State subjects, the construction of HEPs is often delayed due to conflicts among riparian States — the Subansiri HEP is a prime example of this.
- Environmental clearance would remain necessary for HEPs.
- Several HEPs were dropped or had their design and capacity modified due to environmental considerations.
- Parameters like e-flow, free flow stretch, eco-sensitive zone, impact on wild flora and fauna are now better defined.
- Therefore, the hydropower potential including pumped storage hydropower, should be reassessed using modern technology and environmental considerations.
- Thermal projects do not require techno-economic clearance (TEC) from the Central Electricity Authority (CEA), but for HEPs with capital expenditure above ?1000 crore, the concurrence of the CEA is required.
- Site-specific changes required during construction also need approval.
- Clearance is given in consultation with the CWC, and takes an inordinately long time.
- Processes must be revisited to reduce the time taken for the TEC. A unit of the CWC may be co-located within CEA itself.
- Hydropower projects are more than engineering ventures. They have large-scale socio-economic and environmental implications.
- HEPs often encounter geological surprises during construction. The land acquisition process is elaborate, requires public hearing and approval of the Gram Sabha. Forest clearances take time.
- Resettlement and rehabilitation (R&R) issues are not only sensitive but also entail substantial cost. It has been experienced that projects do not envisage adequate cost on these items at the approval stage.
- Subsequent arrangement means cost and time overruns. Adequate R&R cost should be made integral part of the project cost. The project management team should also include experts from social science, environment as well as communication.
- If HEPs could be allocated after obtaining requisite clearances on the pattern of Ultra Mega Power Projects, it would avoid undue delay and cost overrun.
- HEPs are located in difficult and inaccessible sites. They require the development of roads and bridges for project implementation. Roads and bridges provide higher opportunities for the development of neighbouring areas.
- Hence, the Government of India has decided to give budgetary support for them. However, the process to grant financial support needs to be streamlined. Large HEPs perform flood moderation also, but they do not get any grant unless declared a national project by the Ministry of Water Resources. The Ministry of Power has now decided to support flood moderation. These measures would certainly make the cost of power workable.
- HEPs have debt-equity ratio of 70:30 and their tariff is designed to recover debt in the initial 12 years. This frontloading of tariff makes hydro energy unviable. The government has now allowed debt repayment period and project life as 18 years and 40 years respectively, and has also introduced an escalating tariff of 2 per cent annually to reduce the initial tariff.
- Requisite changes in tariff regulations are required to operate them. Though the tariff can be rationalised, it may not address cost and time overrun. Geological surprises, R&R issues and environmental factors result in several unforeseen situations not envisaged in the construction contracts, and lead to unnecessary arbitration, litigation, and delays in implementation.
- Delayed or deferred payments incapacitate contractors financially. Therefore, a robust and reliable mechanism for quick resolution of contractual conflicts must be contrived in the system to fast-track implementation of HEPs.
Solutions for Hydropower
- India is committed to have 40 per cent of its installed capacity from non-fossil fuel sources by 2030, and is pursuing a renewable target of 175 GW by 2022 and 450 GW by 2030. Therefore, hydropower is highly relevant for grid integration of renewable energy and for balancing infirmities.
- Significant reforms made in recent years include the 2008 Hydro Power Policy encouraging private sector participation and the 2016 National Tariff Policy on frequency response markets and extended certainty of power purchase agreements.
- The Central Electricity Authority (CEA) and Ministry of Power have also been actively monitoring and fast-tracking priority schemes, notably the 50,000 MW Hydro Electric Initiative.
- The government formally recognised large hydropower as renewable in 2019. This means that these projects built after March that year will be able to benefit from the renewable purchase obligation. Previously only projects up to 25 MW were considered renewable.
- Policy proposals mooted by observers include new ancillary service markets, attributing hydropower full renewable status along with separate purchase obligation benefits, and more integrated planning.
- Draft policies under preparation are expected to support stalled hydropower projects and private sector uptake and could include measures to make hydropower tariffs more competitive.
- In 2020, the country’s hydropower sector was heralded for restoring electricity to tens of millions following a huge plunge in demand.
- In 2019, the Teesta-V hydropower station in Sikkim was rated as an example of international good practice in hydropower sustainability, following an independent assessment.
- Courtesy the Draft Electricity (Amendment) Bill 2020, hydropower purchase obligation (HPO) may appear to become a reality soon.
However, a better option is re-engineering of the power market to treat hydropower as a peaking and grid-balancing power, and also to distribute its higher tariff over the entire energy consumption on a prorated basis.
List of Hydroelectric Power Plants in India
Facts about Hydroelectric Power plants in India
- The Koyna Hydroelectric Project is the largest completed hydroelectric power plant in India. It has a power capacity of 1960 MW.
- The first hydroelectric power station was the Shivanasamudra hydroelectric power station.
- Tehri Hydro Electric Power plant is the highest hydroelectric power project in the country, also Tehri Dam is the tallest one in India. Now, NTPC has taken over the project (Since 2019).
- Srisailam Hydro Power Plant is the third largest working project in India.
- Nathpa Jhakri Hydroelectric Power Plant is the biggest underground hydroelectric power project in the country.
- Sardar Sarovar Dam is the world’s second-largest concrete dam.
- Wildlife comprises animals, birds, and insects living in forests. With large regional variations in physiographic, climate, and edaphic types, Indian forests offer a wide range of habitat types that are responsible for a large variety of wildlife in India. India boasts of more than 80,000 species of animals which is about 6.5% of the world’s total species. Indian fauna includes about 6,500 invertebrates, 5,000 molluscs, 2,546 species of fishes, 2,000 species of birds, and 458 species of reptiles, 4 species of panthers, and over 60,000 species of insects.
- The elephant is the largest Indian mammal which only a few centuries ago, was found in large numbers in vast forest tracts of India. There are about 6,000 elephants in the forests of Assam and West Bengal, about 2,000 in Central India, and nearly 6,000 in three southern states of Karnataka, Kerala, and Tamil Nadu.
- The one-horned rhinoceros, India’s second-largest mammal was once found throughout the Indo-Gangetic Plain as far west as Rajasthan, The number of this mammal has drastically deceased and now there are less than 1,500 rhinoceroses in India, confined to the restricted locations in Assam, West Bengal and UP. They survive under strict protection in the Kaziranga and Manas sanctuaries of Assam and the Jaldapara sanctuary of West Bengal.
- The Arna or wild buffalo is found in Assam and in the Bastar district of Chhattisgarh.
- The gaur or the Indian bison is one of the largest existing bovine and is found in the forests of Central India.
- The fourth cycle of the Tiger Census 2018 counted 2976 tigers which is 75% of the global tiger population. Tigers in India mainly found in the forests of eastern Himalayan foothills and in parts of peninsular India. The number of Cheetahs had fallen to less than one hundred until a successful breeding program in the Gir sanctuary in Gujarat resulted in some recovery. The arboreal clouded leopard is found in northern Assam while the Black Panther is a widely distributed predator.
- Asiatic lions living in Gujarat’s Gir forests, with their population going up from 523 in 2015 to 674 in 2020.
- Brown, Black, and Sloth Bear are found at high altitudes in the north-western and central Himalayas.
- Yak, the ox of snow, is largely found in Ladakh and is tamed to be used as a draught animal.
- Stag or Barasingha is found in Assam, Chhattisgarh, and Madhya Pradesh.
- Besides these, several species of monkeys and langur are found in almost all the forest areas of India.
- The Chinkara or the Indian gazelle, the blackbuck or the Indian antelope, the nilgai or the blue bull, the mouse deer or the Indian chevrotain, the chawstaga or the four-horned antelope, wild dog, the fox, the jackal, and the hyena, are the other mammals found in the Indian forests.
- India also abounds in the number of reptiles, although many of them are now endangered species. There are more than 200 species or subspecies of snakes, the best known being the Cobra, Krait, and Russel’s Viper. These are poisonous snakes while Dhaman is a non-poisonous large snake.
- The Blunt Nosed or Marsh Crocodile (the Magar or Mugger) and the long-nosed Gharial are important large-sized reptiles, although their number has drastically reduced. The Big Estuarine Crocodile is still found from the Ganga to the Mahanadi.
- India is extremely rich in birdlife. There are about 2,000 species of birds in India which is about three times the number of species found in Europe.
- Some birds such as ducks, cranes, swallows, and flycatchers migrate from central Asia to the wetlands of Bharatpur(Keoladeo National Park) every winter. Recently, some migratory birds have been seen near Mathura.
- Indian bird-life has all the varieties of birds which includes:
(i) Aquatic birds include a large variety of storks, herons, ducks, flamingoes, egrets, and cormorants.
(ii) Ground birds (Gallinaceous birds): The Great Indian Bustard, peafowl, jungle fowl, quail, and partridge are the main ground birds.
(iii) Arboreal birds (tree-dwelling): mynas, pigeons, parakeets, doves, cuckoos, rollers, beaters, etc. are other important birds.
Preservation of Wildlife
- Indian Board for Wildlife was constituted in 1952. The main purpose of the board was to advise the Government on the means of conservation and protection of wildlife, construction of national parks, sanctuaries, and zoological gardens as well as promoting public awareness regarding conservation of wildlife.
- Wildlife (Protection) Act, 1972 is a comprehensive law that has been adopted by all states. It governs wildlife conservation and the protection of endangered species. The Act prohibits trade in rare and endangered species.
- Project Tiger, one of the premier conservation efforts in the country was launched in 1973. It is a centrally financed scheme under which 51 Tiger Reserves have been set up in 18 states. India now has as many as 2,967 tigers in the wild (Census 2018), with more than half of them in Madhya Pradesh and Karnataka, according to the latest tiger estimation report for 2018. The population of tigers has increased by 33% since the last census in 2014 when the total estimate was 2,226. The fourth cycle of the Tiger Census 2018 counted 2976 tigers which is 75% of the global tiger population.
- Project Elephant was launched as a centrally sponsored scheme in February 1992. According to recent reports, the elephant population in India is demonstrating a stable trend across elephant reserves in India. The population of elephants in the year 2012, was estimated at 31,368 while it had fallen to 27312 in 2017. The elephant population of India was 27,682 in 2007. The average population throughout the period was about 26700.
- Crocodile Breeding Project– This project was initiated on April 1, 1974, and the project began on April 1, 1975, in Odisha. Crocodile husbandry work was undertaken with a view to sanctuary development.
- The National Wildlife Action Plan (NWAP) provides the framework of strategy as well as the program for the conservation of wildlife. The first National Wildlife Action Plan of 1983 has been revised and a new Wildlife Action Plan (2002-2016) has been adopted. The Indian Board of Wildlife is the apex advisory body overseeing and guiding the implementation of various schemes for wildlife conservation.
- National park is a relatively large land or water area which contains representative samples and sites of major natural regions, features, scenery, and/or plant and animal species of national or international significance and is of special scientific, educational and recreational interest. Usually, the national parks contain one or several entire ecosystems that are not materially altered by human exploitation or occupation. National parks are protected and managed by the government in a natural or near-natural state. Visitors enter under special conditions for inspirational, educational, cultural, and recreational purposes.
- Wildlife Sanctuary is more or less similar to a national park which is dedicated to protecting wildlife and concerned species. A wildlife sanctuary is an area constituted by the competent authority in which killing and capturing of any form of wildlife is prohibited. Grazing or movement of livestock is regulated. The chief warden is authorized to allow or disallow entry into the sanctuary or construction of roads, buildings, fences, etc. Hunting is also restricted and strictly regulated. The status of Wildlife sanctuary is equal to the IUCN category IV protected area.
- Biosphere Reserves. A biosphere reserve is a unique and representative ecosystem of terrestrial and coastal areas which are internationally recognized within the framework of UNESCO’s Man and Biosphere (MAB) program. The objectives of the Man and Biosphere Program (MAB) are as follows:
(i) Conservation function: to conserve genetic resources, species, ecosystems, and landscapes
(ii) Development function: to promote sustainable human and economic development.
(iii) Logistic support function: to provide support for research and analyzing the issues of conservation and sustainable development.