Indian startup develops sand-based gravity energy storage system

Baud Resources, a high-tech startup incubated by IIT Kanpur, has developed a new method of gravity-based energy storage that operates on gravitational potential energy and does not require water, dams or hills, unlike pumped storage. The mechanism can be implemented in any location (plains, deserts or sub-zero climates). It uses locally available materials such as sand and industrial waste such as coal ash or construction waste as payloads and relies on an artificial incline of about 20 meters to 40 meters to lift the sand from the lower station to the upper station and store the energy as potential energy. The sand is lowered when needed to release the energy.

“Our proprietary gravity-based energy storage design (using sand) enables efficient energy storage and discharge,” Baud Resources CEO Disant Mishra told the media. “This mechanism is ideal for long-term energy storage and provides cost-effective power with high round-trip efficiency.”

The startup’s commercial plant, to be announced this year, will offer 100MWh of capacity and a levelized cost of storage of around 2.5 Indian rupees (about 0.22 yuan) per kilowatt-hour.

The system is based on circular economy principles, using locally available sand (from the site itself or nearby) or industrial waste materials such as coal bottom ash from thermal power plants as payload. The height difference of 20 to 40 meters is achieved by on-site excavation and reclamation. The continuous mass flow ensures uniform load distribution, alleviating the concentrated load problems that occur in block-based gravity energy storage designs.

Gravity storage mechanism Image: Baud Resources

The technology is a lightweight, mobile load-transfer project that works between two sites. It does require any permanent steel support structure to suspend the payload. This gives Baud's design an advantage in delivering large-scale plants at a much lower cost than other gravity candidates. Compared to pumped hydro, the gravity storage design also allows for coexistence with existing solar and wind plants. It can be delivered in locations with scarce water resources or sub-zero climates, where pumped hydro may not be a viable or efficient option.

“With the target of 500GW of renewable energy capacity by 2030, the demand for energy storage will rise. The energy storage market in India is expected to reach 350GWh by 2030. Despite efforts in pumped hydro and battery storage, a gap of 150GWh is expected by 2030. We aim to fill this gap with our gravity energy storage system, with an expected capacity of 20GWh to 40GWh by 2030.”

Mishra added that the company is targeting early adopters, initially offering small plants, and then scaling up to 5GWh to 10GWh projects for higher profitability. Its turnkey energy storage solutions are targeted at large renewable energy operators in India, with future plans to expand to the EU, US and MENA markets.

On a per-MW basis, gravity platforms also consume less land than current ground-based solar installations, Mishra said.

He added: “Co-location with solar PV adds a further different dimension as the gravity application can receive direct current directly from the solar panels while returning alternating current to the grid using dual drive generators, eliminating the inverter and its losses. This means greater round-trip efficiency and lower capital expenditure for the combined renewable energy project.”

Baud Resources successfully completed its live demonstration project at IIT Kanpur in November 2023. Following this achievement, it received funding from Skoda Auto to support its ongoing and upcoming demonstration projects.

“Looking ahead, we are poised to announce our first commercial plant by the end of this year, which is expected to be completed by 2025. In addition, we are actively working with two key customers to further strengthen our market presence,” Mishra said.

(Source: Baud Resources Global Energy Storage Network, New Energy Network Comprehensive)