India is quickly increasing its share of renewable energy sources, but still depends on carbon-emitting coal, oil and natural gas for 80 per cent of its electricity needs. The renewable energy industry in India has shown the ability to scale up rapidly, while delivering at a significantly lower cost. India has an ambitious plan to achieve 175 GW renewables by 2022, including 40 GW of rooftop solar, 60 GW of grid-scale solar and 60 GW of wind. According to the Ministry of New and Renewable Energy (MNRE), as of June 30, 2019, India had an installed renewable energy capacity of 80.47 GW, of which solar and wind comprised 29.55 GW and 36.37 GW respectively. The Power and new and renewable energy minister R.K. Singh has said that about 29 GW of renewable energy is under installation.
Large-scale deployment of renewable energy and its use require technical as well as commercial solutions and a variety of policy decisions around minimising the impact of intermittency and enabling grid integration of renewable energy. The falling costs and rising efficiencies of supporting technologies, such as energy storage are already making renewable energy generation compete with conventional thermal power. Such technological advancements and cost reductions in both renewable energy and energy storage options will facilitate the exploitation of abundant renewable resources. The main challenge in meeting the national renewable energy targets is the ability of the Indian electricity grid to integrate these variable resources.
Energy storage technologies can provide an array of services to the modern grid, such as peak load management, grid balancing and renewable energy integration. Historically, storage systems such as pumped hydro were deployed for energy arbitrage; however, emerging distributed energy storage technologies are currently used in many other areas such as grid balancing and renewable energy integration, in addition to energy arbitrage.
Globally, renewable energy plus energy storage is being increasingly seen as an alternative to building peaking power plants. Energy storage integrated with renewable energy generates a smooth and firm output that is controllable, which subsequently optimises transmission investments. A key application for energy storage in transmission is to defer investments on upgrades for new capacity projects required to reduce renewable energy curtailments.
Applications for energy storage related to renewable energy include renewable energy smoothing and renewable energy firming. Renewable energy smoothing addresses the short duration variability in the output of wind or solar energy (typically within 15–30 minutes). Renewable energy firming is the shifting of renewable energy output to times when the grid requires it most (typically two to four hours). Examples of renewable energy firming include shifting part of the solar photovoltaic output from 11 a.m.-2 p.m. to 6-9 p.m. to meet the evening peak or shifting peak and wind output from the early morning hours to 7 a.m. to 10 a.m. to meet the morning ramp-up on the grid. Apart from this, energy storage can be used to provide reactive power support to improve renewable integration, particularly on weaker distribution feeders.
With the technology becoming affordable, renewable energy developers need to explore new business models and start deploying hybrid projects that can help India capture the true potential of renewable energy in the country. The MNRE released the National Solar-Wind Hybrid Policy in May 2018. This policy aims at providing a framework for the promotion of a large grid-connected wind-solar PV hybrid system for efficient utilisation of transmission infrastructure and land. It also aims at reducing the variability in renewable power generation and achieving better grid stability through the integration of energy storage with such hybrid projects. One of the key constraints in the development of solar and wind projects is access to land and evacuation infrastructure. By co-locating wind and solar projects, the capacity utilisation of power evacuation increases. These two modules make up around 25 per cent of the cost of a renewable energy plant. Using hybrid projects, the wind and solar modules will feed power into the same transmission lines, allowing firms to have almost twice the capacity on each site and obtain better returns on their investments. Hybrid renewable energy projects can also ensure greater contribution in meeting the peak load.
The key challenge for reaching these ambitious targets would be the ability of the grid to integrate the variability associated with renewables, as well as the huge investment required for upgrading the transmission and distribution (T&D) infrastructure. Energy storage can help in better integration of these renewables by providing multiple values to the system such as optimising T&D investments, addressing forecasting errors in wind and solar generation for more accurate scheduling, addressing local reliability issues by providing reactive power support and enabling end-users to manage peak loads and ensuring more efficient utilisation of distributed renewables. With the rapid reduction in the cost of both solar and storage, customers can see solar plus storage as an alternative for peak power from the grid; at the same time, utilities can avoid investments in peaker capacity or eliminate load shedding by utilising these resources.
By supplying power when and where it is needed, energy storage improves the reliability of electricity supply, reduces variability and uncertainty, and increases stability. Better integration of renewables into the system increases efficiency (economic and utilisation) of the existing generation and transmission facilities. It reduces the need for additional transmission assets, and can be the preferred supplier of ancillary services. In 2018, Hero Future Energies commissioned India’s first solar-wind hybrid project in Karnataka to better utilise the available power evacuation facilities. The project’s evacuation capacity remains at 50 MW since the primary aim is to address grid integration concerns around variable power coming from renewable energy. The Solar Energy Corporation of India has recently issued multiple tenders for exploring hybrid projects with energy storage systems (ESSs), including a 1,200 MW renewable energy project with up to 400 MWh of ESS.
Solar plus storage is anticipated to become a viable solution for managing peak loads in the next 12-18 months. For commercial and industrial (C&I) customers who wish to integrate rooftop solar, solar plus storage can provide an economic option in states with higher tariffs for C&I customers. This can fuel exponential growth in storage. Depending on policy developments and implementation by various government agencies, we anticipate that renewable energy and storage hybrid projects will drive growth over the next decade. With the enforcement of grid discipline and penalties for deviations, energy storage will prove to be a valuable asset in grid integration by smoothing intermittencies and will provide ancillary services for improving grid reliability.
With the impending launch of NITI Aayog’s National Mission for Battery Manufacturing, the country is looking to target 50 GWh of annual cell production capacity. The India Energy Storage Alliance is working towards making India a global hub for research and development, and manufacturing of advanced energy storage technologies by 2022. The pace of adoption of renewable energy plus storage is a critical factor that will help India achieve this dream. If we learn from the experience of global leaders such as AES, NextEra, RES Americas and Tesla, I am confident that the Indian renewable energy industry has the potential to meet or exceed the targets set by the government, with support from the emerging energy storage industry.