BW ESS, MIRAI partner on 1 GW of large-scale battery projects in Germany

Zurich-based BESS owner-operator BW ESS has joined hands with Munich-based energy storage developer MIRAI Power, setting out plans to co-develop up to 1 GW of projects in southern Germany. 

As Europe’s largest electricity market, Germany has emerged as the most attractive and dynamic market for BESS deployment amid a growing need for managing negative electricity prices and renewables curtailment risks. However, its large-scale BESS fleet has been lagging far behind the rapid rollout of small-scale system.

According to the data from the German Solar Industry Association (BSW-Solar), around 19 GWh were installed at the turn of 2024. The lion’s share of the figure came from residential BESS totaling 15.4 GWh and far surpassing the total installed capacity for storage facilities with an output of more than 1 MW of just under 2.3 GWh.

However, 2025 is shaping to be a pivotal year for growth of the nation’s utility-scale BESS fleet. As the transmission and some distribution network operators told pv magazine, there were around 340 GW of grid-connection requests from large-scale storage systems at the turn of the year. The nation-wide pipeline could be even bigger.

For BW ESS and MIRAI Power, South Germany will be the focus of their development activities, with the partners describing it as “a region with huge energy storage development potential”.

While MIRAI Power is a newcomer to the BESS scene, established in 2024, BW ESS already has strategic partners in the UK, Australia, Italy, Germany and Sweden and a development pipeline of about 7 GW, with over 1.5 GWh of projects currently in construction.

In October 2024, BW ESS moved to acquire the remaining stake in British renewables business Penso Power, adding 2 GW to its BESS pipeline. Some of its notable developments include the 350 MW/1750 MWh Hams Hall energy storage project in the U.K., which will be supplied by Sungrow, as well as a 2.9 GW pipeline of projects developed with ACL Energy in Italy.

In one of the first BESS tolling agreements in the U.K., BW ESS and Penso Power inked a seven-year, fixed-price deal with Shell Energy, for a 100 MW/330 MWh BESS last August.