At the moment both fossil and renewable energy sources are used. During the energy transition the focus lies on finding new renewable energy sources and developing these further into practical energy solutions. These are renewable energy sources that are already in use, such as solar energy, biomass and wind energy, but also new potential energy sources that are not yet used at a large scale. For instance, hydrogen, methanol and formic acid are interesting to research further. We share the latest findings and developments surrounding energy sources in these articles, as well as the developments surrounding traditional energy sources.