Temporal city-scale matching of solar photovoltaic generation and electric vehicle charging

Fretzen U, Ansarin M, Brandt T

Abstract
The number of electric vehicles (EVs) and solar photovoltaic panels (PVs) are rapidly increasing in many power grids. An important emerging challenge is managing their less desirable consequences (e.g. grid instability and peak load), particularly in urban environments. We present a solution that matches the temporal nature of PV generation and EV charging. This solution is a simple coordination strategy for EV charging which minimally affects EV availability for drivers while maximizing the PV electricity generation absorbed by EV batteries. The strategy is benchmarked with high-resolution data from a medium-sized European city. We find that this coordination provides large benefits compared to commonly-observed uncoordinated charging patterns across seasons and PV and EV integration levels. With charging coordination, almost 71%–92% of the EV charging load can be provided by solar panels in the summer. However, winter’s lower solar irradiance results in a larger range of possibilities (13%–76%), with the exact value depending on the combination of PV and EV integration level. The gains compared to uncoordinated charging are generally highest in winter and similarly vary based on PV and EV integration levels (from 5 to 63 percentage points). Additionally, these benefits do not appear to come at a significant cost to EV availability for drivers.

Keywords
Renewable energy; Electric vehicles; Solar panels