German renewables investor Faveos SE (<a href="https://www.boerse-duesseldorf.de/aktien/DE000A3DCV33/faveos-se-inhaber-aktien-o-n/" target="_blank">DUS:C45</a>) and local biogas plants builder Biogas Service Tarmstedt GmbH have established a joint venture that will be active in the area of large-scale battery energy storage systems, the companies said on Wednesday.