Battery energy storage design optimisation sizing within a peer-to-peer energy sharing community

Abstract

The increase in deployment of microgrids and the mismatch between local energy generation and demand have led to an innovative and versatile peer-to-peer (P2P) energy sharing framework to manage distributed energy resources (DER). P2P energy sharing, described as the energy trade between local prosumers and consumers based on the sharing economy concept, is one effective solution that allows excess energy from prosumers DER to be traded within their local community. P2P energy sharing exhibits superior advantages in terms of local power self-consumption, self-sufficiency and return on local generation investment compared with the conventional peer-to-grid (P2G) trading. Existing studies have shown the benefits of battery energy storage systems (BESSs) inclusion, but do not consider optimal BESS sizing with P2P energy sharing under different BESS ownership.

For microgrids of grid-tied solar photovoltaic (PV) prosumers, two different optimal BESS ownership structures under the P2P framework, namely the ESP owned BESS structure and the User owned BESS structure, are investigated in this study which are compared to the traditional User owned BESS structure under the P2G framework. An optimal BESS sizing model is proposed for a P2P energy sharing network (ESN) consisting of a centralised BESS owned by a third-party energy sharing provider (ESP). A multi-objective optimisation model, considering the ESP energy storage investment net present value and the ESN energy costs, is formulated incorporating the supply and demand ratio for the ESN internal pricing mechanism. It is found that for a university campus network case study that the P2P structures are more economically beneficial as they achieved greater NPVs in comparison to their BESS size. The most desirable BESS ownership structure, with the greatest NPV of $1 397 770.04 and an overall reduction in BESS size of 10%, is the User owned BESS structure with P2P energy sharing. However, that is assuming that all prosumers are willing and financially capable of investing in a BESS. The ESP owned structure was found to be less economically beneficial for the prosumers, but provided the opportunity for prosumers to engage in P2P energy sharing and reduce their energy costs without a BESS investment cost. A simplified BESS operation control is also realised with this structure.

Finally, the simulation results from the case study show an approximate linear interaction between the ESP optimal li-ion battery energy storage sizing with the amount of P2P energy sharing and the energy cost for the ESN under the time-of-use tariff. The larger the li-ion battery, the more P2P energy li-ion battery, decreases the BESS NPV and possibly making its deployment infeasible.