Solar plus storage is already cost-competitive across much of southern and northern Europe, and will hit grid parity across the continent by 2025, according to a new study conducted by a solar photovoltaic researcher with support from industry.

The paper by Christian Breyer, professor of solar economy at Finland’s Lappeenranta University of Technology, looked at six cities across the continent and found that solar costs fell below the average hourly price of grid electricity (the “spot price”, in industry parlance) in 2018. The solar cost calculation was based on the “levelized cost of energy” (LCOE), a calculation that allows analysts to compare the lifetime cost of different electricity generation options.

“Solar competitiveness—understood as the gap between average spot market prices and lower PV LCOEs –was most pronounced in high-irradiation Spain and Italy, followed by the UK, France, Germany, and Finland,” PV-Tech reports, though solar came in less expensive from Málaga to Helsinki. “The findings, the study said, should help steer the ongoing global debate on how to tackle climate change.”

The cost data wasn’t easy to track down, since “investors do not usually publish their budgets,” the researchers said. But “policy-makers need to be informed that PV is the cheapest form of electricity, especially if its inherent low…risks are taken into account.”