When will the start-ups enter the play field of energy innovations in mass? The energy sector has traditionally been a challenging industry to new entrants, especially for smaller firms. Digitalization, decentralization and new renewable energy technologies are enabling also smaller actors to create energy-related innovations. This research focuses on understanding the level of business model readiness of start-ups when commercializing energy innovations. We interviewed start-up companies and provide an analysis of the state of their business models mapped with key challenges that these firms face. Our results show that while most start-ups have a promising value proposition they struggle with other value creation and value capture aspects. Especially building the sales channel that often requires co-operation with energy industry incumbents and finding the right revenue model causes problems to the startups. The challenges the start-ups face also depend on their focus; technology-based start-ups appear to have more obstacles than data-driven start-ups due to longer time needed to mature the products for commercial deployment.