Electric car as electricity storage – promising simulation
Simulations carried out as part of a bachelor’s thesis in the Building and Energy Technology degree programme at the University of Applied Sciences Burgenland have come to an extremely positive conclusion: electric cars as home storage units can reduce electricity consumption by up to 51 percent. Electricity costs can be reduced by up to 1,400 euros and CO2 emissions by 370 kg/year.
Electric cars can do more than just provide environmentally friendly mobility: as flexible home storage units in combination with a photovoltaic system, they increase independence from the power grid and significantly reduce costs. At least they have the potential to do so. This is demonstrated by Christoph Paar’s bachelor’s thesis in the Building and Energy Technology degree programme at University of Applied Sciences Burgenland. Various sizes of PV systems, vehicle types and charging and consumption profiles were examined in simulation-based analyses for a typical residential building – with a clear result: vehicle-to-home (V2H) has the potential to make private energy systems noticeably more efficient.
“If you can charge your electric car bidirectionally, you can turn the car park on your doorstep into an energy storage facility – and make significant cost and CO₂ savings,” says study author Christoph Paar.
“The results show that electricity consumption from the grid can be reduced by up to 51 per cent compared to uncontrolled charging. At the same time, the PV system’s own consumption increases and both feed-in and consumption are distributed more intelligently.” Christoph Paar, student on the Bachelor’s degree programme in Building and Energy Technology
Background: Electric mobility meets energy management
The starting point of the work is a current trend: according to BEÖ, 257,717 electric vehicles were registered in Austria by December 2025. With an average battery capacity of around 65 kWh, this results in a theoretical storage capacity of around 16.75 GWh – a considerable buffer that has so far remained mostly unutilised. This contrasts with typical household consumption: single-person households require an average of 1,900 kWh per year, three-person households around 4,200 kWh. This is where V2H comes in: Surpluses from the PV system are stored in the car and fed back into the house when needed.
Key findings of the bachelor thesis
The study shows: The benefits are particularly great if the PV system is small to medium-sized and generation and consumption do not always take place at the same time. In these scenarios, the annual electricity costs in Christoph Paar’s simulation fell by over €1,400 in some cases. In addition, CO₂ emissions per vehicle were reduced by up to 370 kilograms per year. V2H also makes sense for larger PV systems – although the relative additional benefit decreases, the energy flows can be further optimised.
“The greatest effect is achieved when photovoltaic generation and household load are not perfectly synchronised,” says Paar. “Then the vehicle closes the gap between midday sun and evening consumption as a mobile storage unit. V2H is therefore a realistic building block for greater self-sufficiency and a clean, affordable energy supply in the home.”
