Roofs still offer enormous potential for solar electricity generation. In order to achieve the ambitious expansion targets of the German government, this potential must be raised. In a new project, Ecologic Institute and the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) analyze different system concepts and evaluate their economic viability. Existing barriers to the expansion of photovoltaic systems on buildings are identified, and the extent to which the Renewable Energy Sources Act 2023 will remove these barriers is examined. As a result of the project, recommendations for further improvements of the regulatory framework will be elaborated.

The focal points of Ecologic Institute's work in the project are:

• Analysis on the status quo of the use of photovoltaics (PV) in the building sector: with a focus on rooftop systems, this project will provide an overview of the state of expansion of PV systems in the building sector.
• Furthermore, legal, technical, and economic barriers for PV systems are identified. A distinction is made between the different segments. These include installations in the one- and two-family house sector, which are generally aimed at self-supply, installations on multifamily houses – with or without tenant electricity subsidies - and installations on commercially used buildings.
• Analysis of relevant EEG regulations and other legal frameworks: Current regulations that influence PV use in buildings are analyzed, and the expected effects are evaluated. The focus in terms of European law is on the pending legal acts from the Fit For 55 package and the REPowerEU plan of the EU Commission. In terms of national law, the focus is on the innovations following the German government's so-called Easter Package, including amendments to the Renewable Energies Act (EEG) and a law on financing the energy turnaround in the electricity sector (Energy Financing Act – EnFG). In addition, the Building Energy Act (GEG) will also be considered.
• Elaboration of improvement options: Finally, proposals for improving the existing legal framework are to be developed. Legal, technical, and economic aspects are to be considered separately.