Connected Energy E-STOR and M-STOR Second-Life BESS

Connected Energy is a UK company established in 2010, headquartered in Newcastle upon Tyne with a technical centre at Hethel, Norfolk. It turns used electric vehicle battery packs into stationary battery energy storage systems, giving automakers a market for retired batteries and giving energy users lower-cost storage.

E-STOR serves commercial sites, while M-STOR is a modular multi-MW system built from standardised power blocks of second-life EV batteries, offering 1.45 to 5.8 MW of power and 3.8 to 100 MWh of capacity with 2.3 to 11.7 hours of duration. Cloud control software provides real-time monitoring and AI-based analysis and optimisation. Customers and partners include Umicore, Volvo, Renault Group and public sector bodies across the UK and Europe.

• Second-life packs: systems use whole EV battery packs from automotive manufacturers rather than new cells.
• Modular scaling: M-STOR power blocks combine to 3.8 to 100 MWh behind or in front of the meter.
• Long duration: configurations from 2.3 to 11.7 hours suit energy shifting and grid services.
• Revenue stacking: one system can join frequency response, arbitrage and peak shaving markets.
• Monitoring software: cloud platform with real-time visibility, reporting and AI-based optimisation.
• Flexible finance: capex purchase, Battery-as-a-Service lease or revenue-share partnership.

Electric bus operators and EV makers in Vietnam can turn retired packs into storage at depots. Industrial parks can pair second-life storage with rooftop solar for peak shaving. Fast-charging hubs on highways can use storage to work around limited grid capacity.

The company states that M-STOR projects can reach an ROI of 12 to 18 percent depending on configuration, and that customers typically earn more than GBP 100k per MW per year from grid services. Battery-as-a-Service and revenue-share models cut upfront capital, and reusing EV batteries lowers lifetime cost and carbon footprint compared with first-life systems.

Large volumes of EV batteries will reach end of first life over the coming decade while demand for grid and behind-the-meter storage grows with renewables. Vietnam is adding electric buses, motorbikes and cars and is expanding rooftop solar and storage, so second-life storage offers a lower-cost, circular option for factories and charging hubs.

Established in 2010 in the UK. Investors across rounds include Macquarie, ENGIE New Ventures, Sumitomo Corporation, Caterpillar Venture Capital, the Hinduja Group, Mercuria, OurCrowd and Volvo Energy (GBP 15 million round in 2022). Partnership with Forsee Power signed in May 2025 and a 100 MWh project in France announced in September 2025.