Energy storage and multi energy systems in local energy communities with high renewable energy penetration. (October 2020) - Bartolini, Andrea
Abstract: This study investigates how a district with a high capacity of non-controllable renewable electricity generation can entirely self-consume its production at a community level either directly or for heating and cooling, thus potentially fulfilling the concept of "Renewable Energy Community". It investigates the potential role of storage systems and polygeneration in renewables self-consumption, by also exploiting the synergies among different energy networks in a real residential district with high PV penetration. Two scenarios were modeled other than the "baseline": the first one evaluating the optimal portfolio of energy conversion and storage technologies, and a second one achieving the same goal only using batteries. Both scenarios proved to be a viable solution to exploit the excess of electricity production from the PV plants in the district only through local self-consumption. The results show that a multi-energy system is the most cost-effective solution in doing so, exploiting polygeneration technologies (CHP) and the storage of energy as thermal, electrical, and chemical through power-to-gas. In particular, the least cost solution entails a 42 kWe CHP micro gas engine fueled by a natural gas-hydrogen blend, a 135 kWh battery system, and a 2830 kWh hydrogen storage. Highlights: P2G coupled to polygeneration is a viable solution to store renewable energy. Cost-effective optimal solution consists of cogeneration, electric and hydrogen storages. The use of only batteries is too expensive to store the excess of renewables in a district. Batteries are more effective than P2G with hydrogen due to the higher roundtrip efficiency: 90% vs. 23%. Synergies among energy networks and distributed generation can reduce the power ramp.