The ENTRUST project provides a mapping of the energy system in Europe and aims to achieve an in-depth understanding of how human behaviour around energy is shaped by both technological systems and socio- demographic factors. This report corresponds to the third deliverable foreseen in Work Package 2, which focuses on analysing the role of key actors in the European energy system and characterising the novel technologies and business models emerging in the energy transition. Within this context, Deliverable 2.3 “Report on novel business models and main barriers in the EU energy system” comprises a mapping of the emerging business models in the energy system as well as a clarification of its elements, sources of innovation, and main barriers. The first part of the deliverable introduces the game changing scenario taking place and presents the role of business models in the sustainable energy transition. Megatrends – such as energy availability and security, resource depletion, the technological revolution and urban development – affect and challenge the energy value chains in the energy system. These trends and its multiple implications for the energy sector are discussed in this section. The main barriers that slow down the transition towards a more sustainable structure are also presented. Innovation has played a key role in the energy system but often the term is misunderstood and confused with others like creativity, change, or invention. The next section defines what innovation means for this project and it also gathers the different classifications of innovation found in the literature that help to categorise emerging business models. “Ten types of innovation” and “the business model innovation grid” are two powerful tools that frame different sources of innovation. From them, our own classification of innovation is created to classify the business models we have identified. Moreover, a review of the three framework tools – Osterwalder & Pigneur’s Canvas, IDEO, and Fluidminds – currently applied in the innovation ecosystem to characterise business models was conducted in order to define the most appropriate one for ENTRUST. These framework tools help us to understand how an organisation creates and delivers value, makes money and visualises its structure. The next part of the report examines the emerging business models that correspond to the four energy- intensive sectors that have been selected in the scope of ENTRUST (buildings, urban transport, energy production and the manufacturing process industries). For each business model identified an overall description, along with some real cases, and the business model framework created for Entrust are presented. In addition, an analysis has been conducted to identify which type of innovation is occurring in each sector and at what specific stage of the value chain.