Renewable energy and sustainability expert Dr Ajay Mathur has been a key player in India’s energy transition. The former Director General of the International Solar Alliance (ISA) and currently Professor of Practice at the School of Public Policy, IIT Delhi, describes the last decade of solar development in India as a solar revolution. He says India has moved from being roughly marginal in 2014, when it had about 2.8 gigawatts, or 2,800 megawatts, of (installed) solar capacity, to crossing the 150-gigawatt mark today.
He says this 50-fold increase is the result of very strong policy signals and the ability of policymakers to learn from conditions on the ground and make appropriate policy adjustments. Mathur notes that the Production Linked Incentive (PLI) scheme has enabled domestic manufacturing and improved the reliability of supply chains. He adds that the competitive bidding process has been one of the major reasons behind the 50-fold increase in solar capacity.
Mathur further points out that solar prices have fallen dramatically to the extent that solar electricity combined with batteries, providing round-the-clock power, is now equal to or even cheaper than coal-based electricity.
On the government’s recently announced targets for 2035, he says the key issue is not how the targets are reached but how the additional capacity is integrated efficiently. Mathur notes that future expansion cannot rely on vanilla solar alone and must be supported by access to batteries, adequate land availability, timely construction of transmission lines alongside solar projects and sufficient upfront financial resources, as the initial cost of solar installations remains higher than that of fossil-fuel-based systems.
Referring to NITI Aayog’s estimate that approximately 5,000 gigawatts of solar capacity will be required to achieve net zero by 2070, Mathur says states will have to take the lead in developing new sites. He explains that states need policies under which farmers find it beneficial to transfer land for large-scale solar projects.
He adds that floating solar can be deployed wherever water bodies such as dam reservoirs are available. Mathur also says there needs to be much greater focus on agrivoltaics, alongside efforts to aggregate solar plants and connect them efficiently to the grid. He stresses that rooftop solar must be given much greater importance.
On the issue of installed capacity versus generation mix, Mathur says that while installed solar capacity is high, solar contributes only about 17% to electricity generation. He argues that the focus going forward should be on creating enough capacity so that daytime solar generation can charge batteries or support pumped-storage systems.
Mathur emphasises that storage is essential. Addressing concerns about the duck curve challenge already emerging in the Indian grid despite solar accounting for less than 20% of generation, he says the only way to address the issue is by adding more storage.
He notes that battery energy storage costs have fallen dramatically to the point where solar combined with batteries can produce electricity at a lower cost than coal. However, Mathur says the main challenge remains the upfront capital requirement. He believes government subsidies and viability gap funding are making projects much more viable.
He further says that a market needs to be created for battery storage, including decisions on when battery power is used, how it is valued and paid for, and the provision of contracts that combine solar and battery storage.
On financing the large investments needed for storage and transmission infrastructure, Mathur says that if the levelised cost of new technologies is lower, as it currently is, adoption will happen. However, he notes that the initial cost remains higher.
Mathur says it would greatly help if guarantee-type instruments were established to make projects more attractive for banks to finance and to support the higher upfront investment requirements.
Discussing perovskites, which he notes remain at a niche stage, Mathur says laboratory experiments have demonstrated efficiencies of more than 30% using perovskite-based cells. However, he points out that perovskite degrades very quickly when exposed to air and moisture. He says the major challenge is therefore durability, but adds that there is a belief that, in the future, solar cells could be based entirely on perovskite technology.
