Solar Charging Electric Vehicles: Analysing the charging efficacy of an off-grid, solar powered electric vehicle charging system in long stay carpark applications

The need for sustainable practises in all walks of society are more pressing than ever, with the effects of climate change being felt worldwide. Furthermore, the increasing share of variable and decentralised power generators coupled with the growing electricity demands from electric vehicles (EVs) at irregular times is placing unprecedented stresses on national power grids. To this end, innovative solutions to these complex issues are required. Electric vehicle solar carports (EVSCs) are structures that provide shelter for cars parked under a canopy roof fitted with PV modules. Adjacent to these parking spaces are the EV chargers, powered with the solar generated electricity. The aim of this study was to develop an accurate model and simulate an off-grid EVSC system for long stay parking applications, more specifically for the case of Lelystad Airport. The base case consisted of ‘dumb charging’ which simply split the generated current evenly amongst the actively charging EVs and curtailed any excess. The results of this found that across the year, 85% of EVs left with and adequate state of charge (SOC), defined as being greater than 75% of nominal battery capacity.This was then compared to various other scenarios in a rigorous sensitivity analysis to better understand the influential design parameters and attain a better final SOC distribution. Additionally, an economic assessment was performed, in which the base case was compared to a conventional grid-dependent system as well as a grid-inclusive, PV + grid, system.It was found that the off-grid EVSC system is a profitable investment, and that better system design can result in a better charging performance as well as provide resilience to detrimental scenarios