Europe’s ambitious plans for a renewable energy future are being thrown into doubt by the rising threat of droughts.

A new study tracking 25 European countries from 2017 to 2023 has identified that when droughts strike, hydropower and other renewables do not work as well as they might. As a result, countries will have to fire up more fossil fuel power plants and import energy to keep the lights on.

The team from the Norwegian University of Science and Technology (NTNU) found power production in the EU from fossil fuels increased over the seven-year-period by 180 TWh, which is the equivalent of 7 per cent of the EU’s total generation in 2022, according to a 2023 European Electricity Review.

As climate change makes dry spells more frequent and severe, Europe risks a vicious cycle.

The team explained fossil fuel plants used to fill the energy gap during the seven drier-than-average years the researchers studied emitted an extra 141 million tonnes of CO₂ equivalents. That is more than the total annual emissions from fossil fuel combustion in the Netherlands.

“It’s true that today we are still dependent on fossil fuels to compensate for shortages in renewable energy, but there are solutions that can help us get rid of this dependency,” said Francesco Cherubini, the senior author of the paper and head of NTNU’s Industrial Ecology Programme. “We are on track to move away from this problem, but we still need changes in our electricity systems and networks,” he said.

The research warned drought does not just cause Europe’s CO₂ emissions to skyrocket. Burning fossil fuels also releases air pollutants that have a direct effect on people’s health.

“This is an effect of climate change that people experience directly. This is something that impacts your pocket, because of electricity bills and electricity supplies,” it added.

By mapping each country’s energy mix, the researchers could pinpoint which countries suffered most from excess pollution when fossil fuels were used to fill the electricity gap.

Natural gas was the most commonly used fossil fuels in this situation. Power production from coal and its dirtier cousin, lignite was just one-fifth of that from natural gas.

But pollution from coal and lignite plants was 10 times higher for PM2.5 and 130 times higher for sulphur dioxide compared to pollutants from burning natural gas.

When it came to PM2.5 emissions, Bulgaria, Spain, and Italy topped the charts. That is because they are in a sweet spot where emissions from lignite plants in eastern Europe and from coal plants in western Europe converge.

France was the opposite, droughts actually cut the country’s use of coal, for a variety of reasons. That meant negative PM2.5 emissions during dry spells.

The social and environmental cost of this drought-related use of fossil fuel plants was an estimated $26 billion.

Cherubini says one of the best solutions now is for countries to continue to invest in renewable energy and expand cross-border power interconnections.

Societies need to stop adding more CO₂ to the atmosphere, he explained, because that will absolutely make the problem worse over time.

“This will also reduce air pollution,” Cherubini added. “Renewables are also getting cheaper and are cheaper than investing in fossil fuel fired plants.”

“There’s the goal of reducing imports of fossil fuels from these geopolitical areas for energy security,” he said. “So, there are a lot of positive advantages to the growth in renewables in Europe.”

A warmer planet will mean more, and more severe, droughts. Xianping Hu, a researcher in NTNU’s Industrial Ecology Programme and the lead author of the article, said their findings should be a wakeup call for Europe.

“We need to be prepared when something extreme happens,” he said. “We have to build our systems to be more resilient.”

Global warming can seem abstract, Cherubini added, but when severe droughts affect power prices, it makes this problem concrete.

“This is an effect of climate change that people experience directly,” he concluded. “We are not talking about melting glaciers in the north, or flooding in the tropics. This is something that impacts your pocket, because of electricity bills and electricity supplies.”