Published: 12 Mar 2021, 05:46 By: Molly Lempriere Gravitricity engineering project manager Frances Tierney, with senior mechanical engineer Steven Kirk by the tower. Image: Gravitricity. A new market mechanism for longer-duration storage should be created according to the UK’s Association for Renewable Energy and Clean Technology (REA). In a new report, the trade association — formerly known as the Renewable Energy Association — looked into the need for longer-duration storage and the current challenges facing the technology, with a focus on storage with a duration of up to 24 hours. Technologies could include flow batteries, gravity batteries, pumped hydro, liquid air energy storage (LAES) and compressed air energy storage (CAES).