The power of sand: Can solid gravity close the energy storage gap?

Transition to low-carbon energy systems primarily based on variable renewable energy, such as wind and solar, requires flexibility options, including energy storage. While batteries have dominated the market for short-term electricity storage, existing alternatives for long-duration energy storage are either site-specific, such as pumped hydropower storage (PHS), or lack the required supply infrastructure, such as green hydrogen and other synthetic fuels. We investigate the world's potential and project-specific cost of four emerging gravity energy storage technologies that are carbon-free and can be integrated into existing infrastructure: mountain gravity energy storage, electric truck gravity energy storage, underground energy storage, and lift energy storage technology. These electricity storage technologies can reach a levelized cost of (seasonal) energy storage as low as 94 USD MWh⁻¹ and can store up to nearly 231 TWh of electricity globally (cf., the world's PHS total installed capacity is estimated to be 8.5–9 TWh today). Integrated gravity can play a role as long-duration energy storage in decarbonizing the energy sector and is a complementary solution to short-duration energy storage such as battery energy storage systems (BESS).