India has committed to an ambitious target of developing 175 GW of renewable electricity capacity by 2022, of which it had already installed 90.39 GW by November 2020. Currently, environmentally conscious governments have instituted policies favouring renewable energy and benchmark tariffs of solar electricity have declined below those of thermal power. Hence, with economics and policy favouring renewables and their development, it is inevitable that wind and solar electricity are going to comprise a greater proportion of the Indian energy mix. Correspondingly, renewable energy suffers from twin drawbacks of slow ramp rate and intermittency issues leading to inelastic electricity supply. These issues can only be mitigated by parallel development and investment in various electricity storage technologies such as batteries, pumped hydro storage, flywheels, supercapacitors, compressed air and thermal energy storage, facilitating storage of excess electricity generated and withdrawal during off-peak hours. Coupled with unimpeded growth of renewable energy, energy storage technology is anticipated to be equivalent to 16 TWh by 2030, with battery storage being among the most preferred choices of energy storage owing to its viability, rapidity of installation, innovative edge and uniform usability.
Recent developments in battery storage
In January 2020, Power Grid Corporation of India Limited (Powergrid) in collaboration with the United States Agency for International Development under the Greening the Grid programme project commissioned a pilot battery energy storage system (BESS) of 1.25 MW in Puducherry on a trial basis. The project intends to verify of the techno-economic viability and to determine salutary modes of policy recommendations, regulatory framework and financing methodology that could incentivise BESS installation, conditional on the success of its techno-economic viability tests. The pilot project comprises three packages and the technologies tested were lithium-ion, advanced lead acid and flow battery. All the BESSs are connected to the 22 kV distribution grid. The major functionalities tested in this project were frequency regulation, energy time shift, renewable energy firming, reactive power compensation, voltage support and load following. The technical specifications of the project are given in the table.
Meanwhile, central agencies such as the Solar Energy Corporation of India (SECI) have been working even amidst Covid-19 to come up with multiple energy storage-integrated tenders. Recently, in December 2020, SECI floated a tender for the development of a 20 MW solar power project with a 50 MWh BESS. The project will be installed in Phyang in Leh district of the Union Territory of Ladakh. Earlier, in September 2020, SECI floated a tender for the development of a 100 MW solar project along with a 40 MW/120 MWh BESS in Rajnandgaon, Chhattisgarh. As of December 2020, SECI has issued 373 MW of storage-integrated solar tenders.
Earlier, in August 2020, Bharat Heavy Electricals Limited (BHEL) won its first commercial order for BESS from The Energy and Resources Institute (TERI). The company has signed a contract with TERI for the setting up of a cumulative 410 kWh BESS in the National Capital Territory of Delhi. The tender was issued by TERI on a turnkey basis under UI-ASSIST (US-India Collaborative for Smart Distribution System with Storage) initiative with BSES Rajdhani Power Limited. BHEL’s scope of work in the contract includes design, supply, testing, installation and commissioning, along with a comprehensive five-year annual maintenance contract of the systems at three different locations. BHEL has already commissioned a 1 MWh BESS at its corporate research and development centre located in Hyderabad. The state-of-the-art system is commissioned with three different battery technologies – lithium-ion, advanced lead-carbon and flow batteries.
In terms of viability, there is a strong business case for storage technologies at the utility level. That said, India would have to formulate specific policies intended to encourage the indigenous production of batteries and installation of BESSs, considering that lithium-ion with its high energy density, which is used in most of the batteries, is scarce and batteries would remain expensive without high demand. In addition, there is the virtuous loop created from widespread availability of BESSs, since it will, in turn, push the adoption of rooftop solar and decentralised grids. Addressing these issues will help increase the demand for the BESSs in India.