Following the UN Climate Change Conference 2023 (COP 28) and New Delhi summit of G20 leaders (held in September 2023) and in line with the suggestions made by IEA and IRENA, the global renewable energy capacity needs to be tripled to at least 11,000 GW by the year 2030.

As variable renewables (VRE) grow to substantial levels, electricity systems will require greater flexibility. At very high shares of VRE, electricity will need to be stored over days, weeks or months. By providing these essential services, electricity storage can drive serious electricity decarbonization and help transform the whole energy sector.

Ancillary grid services, such as primary (fast) frequency regulation, secondary frequency regulation, voltage support, capacity reserve and spinning reserve, among others, will grow in significance as VRE penetration increases.

Pumped hydro storage currently dominates total installed storage power capacity, with 96% of the total of 176 gigawatts (GW) installed globally in mid-2017. The other electricity storage technologies already in significant use around the world include thermal storage, with 3.3 GW (1.9%); batteries, with 1.9 GW (1.1%) and other mechanical storage with 1.6 GW (0.9%).

Pumped hydro storage is a commercially mature technology that dominates both the total installed power capacity (in GW) and the energy storage capacity (in GWh). Over three- quarters of energy storage power capacity was installed in only ten countries, with only three – China (32.1 GW), Japan (28.5 GW) and the United States (24.2 GW) – accounting for almost half (48%) of global energy storage capacity. These countries are home to the largest capacities of pumped hydro storage, although they are emerging as significant locations for new and emerging electricity storage technologies.

In this context, India has set up an ambitious target of achieving 500GW of renewable energy by the year 2030. With current capacity of RE power from various sources including conventional hydropower as 175GW, 325GW RE capacity will need to be added in the next 6-7 years. A significant proportion of this 325GW will be addressed from PSP. In the last 3 years, there has been a significant impetus by various stakeholders towards development of PSPs in India.

Ministry of Power (Government of India) issued guidelines for development of PSP projects in 2022. Central Electricity Authority (CEA) came out with guidelines for appraisal and concurrence of DPRs of PSP projects in June 2023. Several state governments have allocated the PSP project sites to the private developers on MoU basis.

About 90 PSP projects with each having installed capacity ranging from 500MW to 3000MW with average installed capacity of 1200MW have been allocated. The aggregate capacity of the projects allocated is in the order of 100GW.

Most of these projects have applied and obtained the scoping clearance from Ministry of Environment, Forest and Climate Change (MoEF & CC) as per EIA notification 2006.

Thus, most of these projects are in survey or investigation stage. It takes at least 2 years to complete mandatory DPR studies, CEA concurrence, environmental approval, forest clearance and land acquisition processes. Therefore, several of these projects will be in execution from 2026 onwards.

Considering that it takes 4 years to execute a PSP project, several of these projects will be commissioned by 2030. However, several other projects may spill beyond 2030 as well.

Meanwhile, it seems that the further identification and allotment of PSP sites to private and public developers will continue and, in the process, another 100GW capacity may be identified and located for development beyond 2030. It is interesting to note that most of the PSP projects for which studies are in progress are closed loop type and some of the projects are open loop off stream type utilizing one of the existing reservoirs.

The preliminary studies on the pre-feasibility of these PSPs indicate project cost of the order or Rs. 5cr/MW. This results in Tariff of the electricity stored as Rs. 5.5 per unit without considering the price of input power. Considering the input power cost as Rs 2 per unit, the output cost works out to be Rs. 7.75Cr/MW. However, these costs may see a further increment with time.

Processes of project approval and implementation of such large number of projects in such a compressed and ambitious time frame shall propel the ecosystem of Energy Transition. However, various regulatory agencies, funding agencies, construction and manufacturing agencies together with the availability of trained manpower to achieve such a big national agenda could be challenged. The project design features will have to be tailor made to suite the topography and geology and the environmental and social setup of the site.