Renewable Energy Communities in Islands: A Maltese Case Study

Abstract

Renewable energy communities are considered as key elements for transforming the present fossil fuel-based energy systems of islands into renewable-based energy systems. This study shows how renewable energy communities can be deployed in the Maltese context to achieve higher penetration of residential-scale photovoltaic systems. Case studies for five renewable energy communities in the Maltese LV distribution network have been analyzed in detail. A novel community battery energy storage sizing strategy was proposed to determine the optimal storage capacity at each energy community. The main objective of the community battery storage in each REC is to minimize the reverse power injection in the grid (minimize the total reverse energy and reverse peak power values), as well as to reduce the peak evening electricity demand. The optimal sizes for communal BESSs were determined to be of 57 kWh (EC 1), 55 kWh (EC 2), 31 kWh (EC 3), 37 kWh (EC 4) and 10 kWh (EC 5), respectively. The community storage systems were observed to reduce the overall impact of all five energy communities on the grid infrastructure. Power system simulations were performed for a typical spring day to evaluate the impact of communal BESS placement on the node voltages for all five energy communities. The results showed that the community storage was more effective at reducing the node rms voltage magnitudes when deployed at the end of the respective energy communities, rather than at the beginning of the community. During peak generation hours, reductions of up to 0.48% in the node rms voltage magnitudes were observed. This contrasts with reductions of only 0.19% when the community storage was deployed at the beginning of the energy communities.

Power Quality Analysis for Light-Duty Electric Vehicles: A Case Study in Malta

“…The impact of renewable energy, which today is mostly driven by switching electronic power converters, in the particular case of Malta has already been investigated in [2][3][4][5] and the particular effects of electric vehicles on the grid were modelled in [6]. The island provides an interesting case scenario for the uptake of light-duty electric vehicles (EVs) since the electrical grid is predominantly a centralized one with the only distributed sources of generation being of the renewable type.…”

“…Given that most EV charger topologies use non-linear circuits based on high-frequency switching of semiconductor devices [10][11][12][13][14], a degradation in power quality is expected to some extent; therefore, the impact on the electrical grid has been widely researched [3,[15][16][17][18]. A high uptake of electric vehicle charging is expected to cause various power quality [15,[19][20][21] issues, such as an undervoltage, a phase imbalance and increased harmonics [22].…”