Engineering researchers at the University of South Australia (UniSA) has conducted a study which shows that it could offer low cost charging, and fill its car parks with electric vehicles, if it could double the amount of solar on its campus.
A study by the UniSA researchers suggests that at 25 per cent EV penetration, its Mawson Lakes campus could slash its annual electricity costs by more than 9 per cent by boosting its solar capacity and supporting free EV charging during the day.
It would also lower peak demand by at least 12 per cent. But with a nominal fee for charging, it says it could support filling all its 800 available car spaces with EVs, reaching 100 per cent penetration.
“We looked at different models to determine the most efficient way to support electric vehicle charging, while decreasing the campus’s net annual energy costs,” says Yan Wu, an UniSA engineering researcher.
By doubling the existing PV (or photovoltaics) on the UniSA Mawson Lakes campus, free smart charging could be available to more than 200 electric vehicles – or 25% of the available parking spots on campus, at no extra cost.
By introducing a nominal charging fee, the campus could support 100% EV penetration in the future, saving more than 20% in energy costs.
“By optimising the PV system, more energy would be exported to the grid, which does not attract any revenue. However, providing EV charging services at a nominal fee using the excess PV generation is a sensible solution,” says Wu.
“By doing so, the campus can potentially support 800 EV cars, the maximum number of parking spaces at Mawson Lakes, while incurring almost the same annual energy costs as that for 25% penetration with free charging.”
The release of the study comes hot on the heels of a company also in South Australia launching a free public charger using PV – but only when solar power is available. Other public fast chargers offer heavy discounts for charging during the middle of the day, when solar is plentiful.
The reason this works is due to the demand and availability of solar power. The more electricity that can be used during the day – when solar is available and can sometimes meet all of the state’s demand at certain times – the less pressure on the grid later in the night.
“Excess power generated by rooftop solar and exported to the grid creates major grid issues as dispatchable power must be ramped up suddenly to replace dwindling solar power later in the day, causing a so-called duck curve,” said UniSA Professor Mahfuz Aziz.
“Workplace charging of EVs helps address this challenge by using excess renewable generation during the day. Prioritising daytime workplace charging reduces pressure on the grid during the evening peak hours by decreasing the demand for home charging of EVs.”
The research paper – published in the journal Renewable Energy – is specifically looking at the Mawson Lakes campus, but the researchers believe it could be scaled up elsewhere.
“Based on the findings of this study, workplaces can support EV charging without necessarily increasing their annual energy cost through PV capacity optimisation in conjunction with appropriate smart charging strategies and tariffs,” the researchers conclude.