Against this backdrop, German TSOs introduced the new project maturity framework.
The project maturity framework
The project maturity framework has applied to large-scale storage projects connected to the transmission grid since 1 April 2026. It all became possible after battery storage systems were removed from Germany’s Power Plant Grid Connection Ordinance (KraftNAV) at the end of 2025.
Rather than allocating connection capacity based on the order in which applications are submitted, projects are now assessed in periodic application rounds. The key criteria include the likelihood of project delivery, the maturity of project development and the anticipated benefit to the electricity system. Where applications exceed available capacity, priority is given to the most advanced projects.
In principle, this approach is sensible. Scarce grid capacity should be allocated to projects that are most likely to be built, while speculative reservations should become less attractive. However, this also shifts much of the project development burden to an earlier stage. Developers must now provide extensive supporting evidence before receiving a grid connection offer, including secured land rights, permitting progress, technical concepts, creditworthiness and financing arrangements. In addition, applicants must pay a €50,000 (US$56,902.50) application fee and provide a security deposit of €1,500 per megawatt.
