Discoms, state govts bet on storage technology to stabilise power supply

To bring about reliable power supply amid increased use of renewable energy, discoms and state governments are investing in storage technologies.

Tata Power Delhi Distribution Company (TPDDL), one of the power distribution companies (discoms) in Delhi, for instance, recently inaugurated a ‘community energy storage system’ in collaboration with Nexcharge.

The project entails setting up a 150 Kw battery storage system at the Ranibagh sub-station of the company in north Delhi.

Though small in size, the project signifies a paradigm shift in the planning of power suppliers.  

TPDDL, in 2019, joined hands with AES and Mitsubishi to set up a 10 Mw grid storage project at its Rohini sub-station.

The project is the largest grid-scale battery-based energy storage system in South Asia. This system charges itself when cheaper power is available and also when frequency is low. It supplies when there is a shortfall.

“Storage systems help improve supply reliability, especially during outage and maintenance. Rather than disconnecting supply to consumers, we shift it to the battery systems. It also reduces the investment of the discoms on transformers as the battery system handles the peak supply,” said Ganesh Srinivasan, chief executive officer (CEO), TPDDL. He added that the latest Nexcharge systems can be easily transported and be taken to areas where supply load is increasing. The system has six batteries currently of 24 Kw each.

Srinivasan said the company is evaluating more such projects that would involve larger-sized storage. “In our areas, we would need at least 100-150 Mw of storage. We are working on all sides of the spectrum – Mw, Kw and very localised supply hotspots,” he said.

In the last five years, the share of renewable sources in the country’s electricity supply basket has increased to 17 per cent from 5 per cent. Due to the intermittent nature of this power, storage becomes a necessity in order to have a reliable power supply across urban and rural areas, discoms and state governments.  

Rajasthan, which is one of India’s prime sites for wind and solar power generation, is now planning storage-based renewable projects. The state will have four mega projects totalling 36,200 Mw with different types of storage technologies.

Adani Green Energy will set up 11,700 Mw hybrid solar and wind power project and ReNew Power will have 10,000 Mw renewable power with battery storage.

Greenko will set up 4,500 Mw of solar and wind power capacity along with pump hydro storage of 2,520 Mw. JSW Energy is expected to set up close to 10,000 Mw of renewable capacity. The company is yet to decide on the storage technology.

Speaking with Business Standard, Subodh Agarwal, chairman and managing director (CMD), Rajasthan Renewable Energy Corporation (RREC), said of all these projects, the Greenko one is unique as it is using pump hydro storage.

“It’s a simple technology but means a world. Excess energy will be used to pump up water from the reservoir, and when it is needed, the same water will be used for generating power from hydro. The project is estimated to cost Rs 30,000 crore and Greenko is confident of providing employment to 6,000 people,” said Agarwal. He added that Greenko is free to sell power to any state. The project would come up in Shahpur, Baran district of Rajasthan.

At the central level, the Solar Energy Corporation of India (SECI), the nodal agency to award renewable projects, has started offering renewable tenders with storage options.

ReNew and Greenko won 300 Mw and 900 Mw projects in tariff range of Rs 4.36-6 per unit. Srinivisan said the renewable project, both at the grid side and rooftop solar side, would need storage support.

“The ups and downs of the power system will happen due to renewable energy. Next big change will be electric vehicles but without maintaining system storage, frequency will become challenging,” he said.

However, there is a lack of regulations. Apex electricity regulator Central Electricity Regulatory Commission (CERC) is yet to come out with a regulation that governs price and technology of energy storage in India.

“There is a lot of interest from the regulators and the ministry as well. But there is no regulation. There is no doubt that storage is an integral part of the future grid. The regulations have to be made by individual state regulators but they need some guiding framework from the central level,” said Srinivasan.

Along with this, cost is also a major deterrent for states or discoms to take up storage projects, especially when the cost of renewable sources is falling.

Rahul Walwankar, president and managing director (MD) of India Energy Storage Alliance (IESA) said the dream of adding 450 Gw of renewable energy by 2030 is not possible without deploying storage technologies at mass scale.

“Cost is actually an excuse. Most of the commercial and industrial consumers pay Rs 8 per unit and above for grid connected electricity. Storage had reached that price parity three years back. This is a missed opportunity. The cost of storage will come down as manufacturing and industrial usage ramps up,” he said.

He further said storage can be used to target low-hanging fruits such as replacement of diesel gensets or be used in areas where the grid is not strong.