The net-metering practice in medium-voltage PV-BES prosumers: A techno-economic analysis of the Greek case

Nowadays, the volatile economic conditions alongside the environmental concerns on using fossil fuels for electricity, necessitate the gradual transition from conventional power plants to distributed photovoltaic (PV) systems. To further promote PV installations, various support mechanisms have been introduced; net-metering (NEM) is considered as one of the most important alternating pricing policies. Nevertheless, the ever-increasing penetration of PVs and especially their intermittent nature may lead to unprecedented technical issues related to the reliable grid operation. To tackle these challenges, battery energy storage (BES) systems are used on the premises of PV prosumers, but their relatively high capital costs and limited lifetime hinder such investments. In this paper, a techno-economic model is introduced to evaluate the viability of prospective PV-BES investments of medium-voltage (MV) prosumers operating under the NEM mechanism by taking also into account the capacity degradation of BES. The focus of this paper is the analysis of the NEM program of MV prosumers in Greece. In particular, the case of the university campuses of the Democritus University of Thrace, Greece, is considered, but the methodology is applicable for evaluating other NEM programs and electricity sectors. The impact of various parameters on the viability of the NEM investments is investigated considering different scenarios. Results show that NEM is generally a profitable mechanism, especially, for prosumers with high load demand. Significant parameters that affect NEM profitability are the load demand growth, the PV and BES degradation, the inflation and the discount rate.

Kalliopi Pippi, Theofilos Papadopoulos, Georgios Kryonidis, Evangelos Kyriakopoulos