Siemens to provide battery storage system to Germany’s SWW Wunsiedel December 21, 2016 | Europe Company News German energy provider SWW Wunsiedel GmbH has awarded a contract to Siemens for the supply and installation of a 6 MW battery storage system based on lithium-ion batteries. This content is available to only paying subscribers. Username or E-mail Password Remember Me Forgot Password