Hydro Electricity Power in India

Hydro is a Greek word, which means water. Hydro electricity is the conversion of the mechanical energy in flowing water into electricity. Hydro electricity is generated when the force of falling water from dams, rivers or waterfalls is used to turn turbines, which then drives generators that produce electricity. The energy produced is directed to a substation, where transformers "step up" the voltage before its transmission to the electricity grid.

Process of energy generation in Hydroelectric Power Plant

The first step in the generation of energy in a hydropower plant is the collection of run-offs of seasonal rain and snow in lakes, streams and rivers, during the hydrological cycle. The run-off flows to dams downstream. The water falls through a dam, into the hydropower plant and turns a large wheel called a turbine. The turbine converts the energy of falling water into mechanical energy to drive the generator After this process has taken place electricity is transferred to the communities through transmission lines and the water is released back into the lakes, streams or rivers.

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.

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.

Challenges related to hydropower

• 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

Hydropower potential in India

The hydropower potential of India is around 1,45,000 MW and at 60% load factor, it can meet the demand of around 85, 000 MW. The estimated potential for power generation from small hydropower projects is about 20,000 MW.

In 1947, hydropower capacity was about 37 percent of the total power generating capacity and over 53 percent of power generation. In the late 1960s, coal-based power generation started displacing hydropower in India and hydropower's share in both capacity and generation fell dramatically. In August 2023, hydropower capacity of about 46,865 MW (megawatt) accounted for roughly 11 percent of power generation capacity. In 2022-23, hydropower accounted for 12.5 percent of power generation in India. India had about 4745.6 MW pumped storage capacity in operation in 2023 with about 57,345 MW of pumped storage capacity under various stages of investigation and construction.

Globally, 4,250 TWh (terawatt hour) of clean electricity was generated from hydropower, one and a half times the entire electricity consumption of the EU (European Union) and more than all renewable generation combined.

Globally, hydropower is the dominant renewable energy source to date, providing over two-thirds of all renewable electricity. Global installed hydropower capacity rose by 26 GW (gigawatt) to 1360 GW in 2021. Globally, 4,250 TWh (terawatt hour) of clean electricity was generated from hydropower, one and a half times the entire electricity consumption of the EU (European Union) and more than all renewable generation combined. But this falls well short of the 45 GW of annual capacity addition that the International Energy Agency (IEA) says is required to meet net-zero goals by 2050 and keep global temperature rises to 1.5°C. To keep temperature rises to 2°C would require 30 GW annually. Around 80 percent of new hydropower capacity installed in 2021 was in China. 4.7 GW of pumped storage hydropower was added to the grid, triple the amount added in 2020. Global growth in hydropower generation capacity was just over 1.9 percent in 2021 which is close to the 2 percent annual average growth required to meet targets set by the Paris Agreement.

Challenges

Large storage hydro-power projects produce low carbon electricity but they also impose huge environmental and social costs. They displace thousands of people, disrupt river ecology, result in large scale deforestation, initiate loss of aquatic and terrestrial biodiversity, negatively alter food systems, water quality and agriculture. These environmental and social costs have led to dam removals in North America and Europe that used to be big dam builders until the 1970s. Now more dams are being removed in North America and Europe than are being built. Even in developing countries where dam building continues, the pace is slowing down because most of the best sites have been taken and also because other sources of renewable energy such as solar and wind are monopolising policy attention and investment.

In the fragile Himalayan mountains where most of India's new hydro-power projects are being developed, devastating floods and landslides have raised risk levels for hydro-projects. In February 2021, sudden flooding in the Dhauliganga, Rishiganga and Alaknanda rivers in Uttarakhand's Chamoli district in took many lives and severely damaged many hydropower projects. Heavy rains in July 2023 and the consequent shut down and damage to hydropower projects resulted in total revenue loss over INR 1.6 billion according to the central electricity authority (CEA). Though there is disagreement over the cause of the 2021 flash floods (glacier crash, avalanche, landslide), there is general agreement that carrying out development projects including hydropower projects, highways, railway lines and mining without adequate appraisals and the disregard for cumulative impact and disaster potential assessments contributed to the scale of the loss.

Widespread indifference for environmental concerns among project developers and the absence of credible monitoring and compliance from regulatory bodies have considerably increased exposure to risks. But this does not mean hydropower projects must be abandoned. There are examples of hydropower projects in India that have met the best international standards. The Teesta-V hydropower station, located in Sikkim was rated as an example of international good practice in hydropower sustainability in 2019. The 510 MW power station, owned and operated by NHPC Limited (National Hydropower Corporation), met or exceeded international good practice across all 20 performance criteria.

For hydropower planning to become sustainable in India the government and industry must prioritize transparency by engaging the civil society, especially those who are directly affected by the project. Research suggests that modular solutions that combine wind, solar, and hydropower provide alternative energy sources that are environmentally, socially, and financially desirable. Instream turbine parks are a much less disruptive alternative to dams and produce energy at a much lower cost. Large, 'smart' hydropower projects may be developed, taking into account the economic, environmental and social concerns of local and downstream communities, in addition to national economic benefits. Technical provisions in smart projects can minimize the impacts on aquatic life and terrestrial ecosystems.

To support hydropower projects, the government of India has included large projects above 25 MW under renewable energy category and has notified hydropower purchase obligation (HPO) as a non-solar renewable purchase obligation (RPO). To facilitate viability, tariff rationalisation with backloading of tariff after increasing project life to 40 years, increasing debt repayment period to 18 years and introducing escalating tariff of 2 percent, budgetary support to building enabling Infrastructure such as roads and bridges and also for flood moderation services have been introduced.

Contribution to grid stability

The most important advantage of hydropower in contrast to other renewable energy sources, like wind and solar, is that it can be dispatched quickly at any time, enabling utilities to balance load variations on the electric distribution system. In India, hydropower's flexibility was best demonstrated on 5 April 2020 when the country's operators restored grid stability following a 31-GW (gigawatt) plunge in demand when most households switched off electrical lights for nine minutes from 21.00 hours to 21.09 hrs. As the event unfolded, generation from hydropower decreased by over 68 percent in a short period without which grid stability would have been compromised.

Pumped hydro storage (PHS) facilities store energy in the form of water in an upper reservoir, pumped from another reservoir at a lower elevation. During periods of high electricity demand, power is generated by releasing the stored water through turbines in the same manner as a conventional hydropower station. During periods of low demand, the upper reservoir is recharged by using lower-cost electricity from the grid to pump the water back to the upper reservoir. PHS projects are unlike traditional hydroelectric stations in that they are a net consumer of electricity, due to hydraulic and electrical losses incurred in the cycle of pumping from lower to upper reservoirs. However, these plants are typically highly efficient and can prove very beneficial in terms of balancing load within the overall power system. Pumped-storage facilities can be very economical due to peak and off-peak price differentials and their potential to provide critical ancillary grid services.

Globally, about 161 GW of PHS acts as the world's largest 'water battery' accounting for over 94 per cent of installed global energy storage capacity. It supports grid stability, reduces overall system costs and sector emissions. India has eight PHS plants with a combined capacity of 4,745 MW, and four PHS plants of 2,780 MW are under construction. Currently out of the total 4,745 MW capacity, only five plants with combined capacity of around 2,600 MW, are being operated in pumping mode. 63 sites have been identified for PHS with total potential of about 96,500 MW. In 2020 the Solar Energy Corporation of India (SECI) concluded the world's largest renewable-cum-energy storage power purchase tender through a reverse auction method. Greenko Group won the auction with a peak power tariff rate of INR 6.12/kWh (kilowatt hour) pairing solar power with PHS.