A group of scientists from Istanbul Technical University, the Turkish-German University, and France’s University of Reims Champagne-Ardenne has developed an economic model to evaluate the potential profitability of EV charging stations backed by solar power.
The new model – described in Economic model for an electric vehicle charging station with vehicle-to-grid functionality, which was recently published in the International Journal of Energy Research – is based on a vehicle-to-grid (V2G) approach. This implies a bidirectional transfer of energy between the grid and the EV. “V2G ensures that EV batteries that are used as storage units provide this stored capacity to grid at peak times and can charge during off-peak times,” the researchers said.
The model considers four main parameters, including EV recharging stations, grid connection, external batteries, and PV installations. EV demand is calculated based on data provided by Turkish company Esarj, which operates 118 recharging stations for EVs throughout Istanbul. The calculations depend on several variables, including arrival and departure times, as well as travel distances. Through a simulation based on this data, the researchers modeled a recharging station serving 10 cars.
Under a business-as-usual case scenario, in which current real prices and demand in Turkey are considered, the value of electricity bought from the network is three times higher than the value of the amount sold, with the tariff for parking generating most of the revenue.
The 25-year simulation of the system resulted in total revenue of €739,310.30, expenditure of €223,851.30, operation and management costs of €166,674.60, annualized investment costs of €3,606.9, and a net present value of €32,625.79.
Another scenario – which considers the consequences of relatively lower power Turkish prices compared to those in the European Union – shows how net present values may vary from the first scenario, depending on hourly parking fees, prices at which power is sold to the grid, charging service fees, and grid power prices.
In a third scenario, based on projections that Turkish power prices will rise leading up to 2030, the operational costs of charging stations could also jump significantly, despite an increase in parking revenue. “Although the net revenue from the sale of energy to the grid decreases due to the decreasing price of selling electricity to the grid, the revenue from the vehicles is three times higher,” the researchers noted.
The simulation resulted in higher revenue compared to the first scenario of €1,398,345, but also in higher expenditures and maintenance costs, at €857,881 and €491,764, respectively. The researchers did not present an annualized investment cost, but the net present value was negative at €51,739, which means that the project would unfeasible under such conditions.
The researchers concluded that a range of factors could affect the profitability of grid-connected EV recharging stations that rely on solar+storage.
“With the development of charging technologies, shortening the charging time, planning the arrivals and departures of the vehicles to the station, and reducing the fare paid to the vehicles at competitive prices will positively affect the interest in the V2G station and the profitability of the system,” the researchers said, adding that the relationship between traffic networks and power grids should be further examined in future research.