India Can Meet All New Power Demand Through Solar and Storage, Not Coal

India can legitimately be proud of its success in developing renewable energy, solar and wind power for the generation of electricity. The non-fossil fuel-based generating capacity has become about half of the total power-generating capacity. As electricity generated by the sun’s rays and wind is variable and inflexible, the challenge of getting supply to match demand at every moment grows as the share of renewables increases. Storage of electricity becomes a necessity. This realisation has led to storage getting more attention in the world as the energy transition gathers momentum. India has been forward looking to putting together the right policies and programmes for storage.

Looking into the medium to long-term future there has been the legitimate concern about our having enough land to put up solar power projects to meet our growing demand. A study by The Energy and Resources Institute (Teri) has, taking a somewhat conservative approach, assessed the solar power potential in the country at over 10,000GW.

A Future Powered By Abundance

To see this in perspective, our total capacity now is around 500GW out of which solar and wind are around 200GW. This potential is more than enough for meeting all our electricity needs as we become a developed Viksit Bharat.

The capacity to store electricity and use it to meet full demand which fluctuates and has sharp peaks must come up along with renewable energy capacity. This is the new emerging electricity supply system. Would meeting additional demand fully with renewables and storage be more expensive? The answer now is a clear “no”.

First, the cost of solar power fell so rapidly that it has been the cheapest source of electricity by a wide margin for some years, around ₹2.50 per unit now. Then, the costs of Battery Energy Storage Systems (BESS) began to fall and have declined by over 90%. The winning bids in recent tenders for BESS have been declining and are now well below ₹2 lakh per megawatt (MW) hour.

A theoretical cost comparison of meeting full demand on four representative days across the seasons in 2022-23 of the BRPL Distribution Company in Delhi from renewables and storage, or, with new thermal power was undertaken using current prices. The results revealed a clear cost advantage of over fifty paise per unit for solar power with storage over new thermal power. The comparison has been done for both battery (BESS) as well as pump storage projects (PSPs). The implication is stark. On purely cost considerations no new thermal power plant should be built.

The scale of capacity creation needed, however, becomes much larger. A Teri study found that for supplying carbon-free electricity on a selected peak summer day, 16,270MW of solar power capacity would be needed. The rule-of-thumb number has been that 4MW of solar capacity gives the same energy as 1MW of thermal capacity. Can we create solar and storage capacity on the large scale that would be needed if the commercial logic of meeting all additional demand from solar and storage is accepted? The answer is yes.

BESS systems can be put up anywhere. The time for installation of grid-scale storage systems is about 20 months, making it attractive for immediate scaling up of storage capacity. The response to the bids that are being invited for these have been highly competitive. New firms, including start-ups, are entering the market.

PSPs, the mature technology of the last century, are being promoted by the government and the response of private developers has been enthusiastic. These projects use electricity to pump up water to a reservoir at a height and this water is released to generate hydropower whenever needed. These can be developed on rivers and at off-river sites. The potential for river sites has been identified at around 190GW. The off-river potential is huge. The first commercially bid off-river project has recently commissioned its first phase in around four years. This is a bit better than the time taken to develop a new thermal plant.

Pathways to a Storage Revolution

Then there are concentrated solar projects (CSPs) which store solar energy in molten salt by using large mirrors to concentrate solar radiation to a molten salt container. The molten salt stores heat which can be used to run a conventional thermal turbine at night and generate electricity. This is now a mature cost-effective technology. The low cost of 7 cents per unit has been achieved in a recently commissioned project in Dubai. CSPs are best installed adjacent to large solar projects. They can use the solar radiation in the area with the transmission capacity being fully utilised, carrying solar power in the day and CSP power at night. India should now begin developing these to increase the pace of storage capacity creation.

Developments in technology and cost reduction of storage require that we move to the new electricity system where all additional demand is met by solar power and storage. This is now the cheapest way of meeting additional demand. The consequential benefit lies in the peaking of carbon emissions from power generation and saving money at the same time. This would be a major milestone for the achievement of the goal of becoming net zero announced by Prime Minister Modi at COP 26 in a major act of global climate leadership.

The author is distinguished fellow at The Energy and Resources Institute.