Although the basis for the energy transition is energy efficiency, renewable energy is essential for the sustainability of our society. One current challenge of the European Commission is to guarantee the autonomy and reliability of the energy supply which requires diversification of the energy mix. Renewable energies play an important role in such context besides leveraging the economy by creating jobs and technological development. In addition, the use of renewable resources allows greater convergence with the European goals of decarbonization and energy efficiency. Innovation can play an important role for the deployment of renewable energy technologies. Some of the most important challenges are: integration into the built environment, energy storage, demand response and smart-grids.