The economics of Solar Home Systems: state of art and future challenges in local energy markets

European Directives 2009/28/EC and 2009/29/EC have identified the power sector as a key driver to achieve the 20-20 20 targets (and those set for 2030 and 2050), as well as Renewable Energy Sources (RES) as fundamental drivers in the pathway from a fossil-based to a zerocarbon energy sector. The development of RES is a complex process involving a great number of decision variables and issues related not only to technical and technological aspects, but also to environmental, social and cultural ones. With the increasing penetration of RES and Storage Devices the design and management of traditional electricity grids is changing, as it requires a shift from a centralized to a decentralized and polycentric system, in which traditionally passive consumers become active prosumers. Such topic is widely debated in literature. There are several contributions on the analysis of RES economic and financial feasibility, which optimize economic benefits by minimizing operational costs; at the same time, many authors address the impacts of selfconsumption on investment profitability. There exists also a conspicuous strand of literature on business models to integrate multiple prosumers into energy markets (e.g., Peer-to-Peer trading, prosumer-to-grid integration, prosumer community groups). Nonetheless, there is a lack of contributions that provide a systematic literature review and a classification of most relevant papers on innovative financial models. The aim of this paper is to present a systematic review and define the state-of-art on valuation approaches to investments in RES production plants coupled with storage. According to a dynamic systematic review protocol, we identified the most relevant contributions and we provided synoptic tables, which summarize main methodological and descriptive aspects and allow for identifying potential gaps in literature and as well as future developments.