Eight EU countries — almost a third of the bloc — plan to phase out coal by 2030, led by France, Italy and Ireland. In the fight against climate change, it’s a major step, but it’s also kind of a no-brainer, considering that 80 percent of the continent’s coal plants are losing money.

But the energy to power Europe has to come from somewhere. And one possibility is to use biomass as fuel — even to convert those coal plants to consume trees and wood pellets instead. It’s a choice that’s subsidized across the EU to the tune of about $7 billion a year, and wood and other solid biofuels still account for the highest proportion of the bloc’s renewable energy (42 percent as of 2017). But that brings a lot of problems.

That’s according to a December report from London-based think tank Sandbag. While nobody is arguing that Europe should be entirely powered by burning wood, as Europe struggles to make its renewable targets, its reliance on biomass may continue to grow. And the depletion of the continent’s forests — and everyone else’s, eventually — isn’t the only argument against wood as a solution to the coal power issue.

“Burning wood emits more CO2 per unit of electricity than burning coal,” explains report author Charles Moore, an analyst at Sandbag. The moisture content in wood is higher than in coal, meaning it burns less efficiently and releases more CO2 into the atmosphere. And while that carbon is often absorbed by so-called carbon sinks like forests, the clearcutting needed would also mean fewer trees to absorb that CO2. In fact, some scientists have proposed mass-planting trees to buy humanity more time to deal with climate change — and old-growth forests usually absorb more carbon than newly planted ones, meaning even fast-growing tree plantations might not do much to help.

Still, to some it’s an attractive option. “Because the EU is phasing out coal, ideally by 2030, there is a need for other energy sources, which means that there is a risk of coal to biomass conversation,” Moore said, blaming “the weakness in EU policy” where biomass is classified as a source of renewable energy with limited caveats. To fix that, environmental groups have lobbied for a stronger focus on renewables like solar and wind power over wood-burning or hydropower, another controversial add to the list of green energies.

EU regulations are currently based on the assumption that biomass should be treated as carbon neutral, explains Mike Norton of the European Academies Science Advisory Council (EASAC). But, as evidenced above, it isn’t — and hopes that the CO2 released would be absorbed by new tree growth or sustainable forestry hasn’t panned out. It’s a “simple assumption which has been exploited and abused to justify millions of tons of forest biomass,” Norton said, adding that the current scale of biomass usage is not renewable. Additionally, biomass — much like coal — has the problem that fuel is often transported to plants over long distances, adding to the fuel’s carbon footprint. As long as biomass is still classed as carbon-neutral fuel, campaigners worry, the phase-out of coal will simply be jumping from one frying pan into a greenwashed version of the same frying pan, rather than providing a boost for actual renewable energy. The percentage of renewable energy subsidies that supports biomass varies by country, but according to National Resource Defense Council reports, biomass gets more than a fifth of the subsidies slated for renewables in Finland, Austria and Belgium.

There’s also no evidence to say that the countries currently providing such wood biomass, such as the U.S., are promoting the expansion of forest, says Duncan Brack of the Royal Institute of International Affairs. Deforestation is the second leading cause of climate change, according to the U.N.’s Food and Agriculture Organization.

There’s a reason for this reliance on biomass, Norton says. “The only way to get a large, swift shift to renewable energy and maintain base load minimum electricity supplies is to exploit the rule that biomass is renewable,” he explains. Such energy would come in handy in the winter or on windless days — but the danger is an over reliance on energies that actually counteract the fight to restrict carbon emissions.

Environmental policy groups have recommended that Europe — and indeed the world — shy away from burning wood as a replacement for coal, instead focusing on solar and wind energy. A report last year found that converting 1 percent of the EU’s land to solar farms would be enough to supply its energy needs.

“The biomass industry only exists at its current scale because it is subsidized,” Brack said. “By simply withdrawing the subsidy, we can stop the growth of these [wood-fueled] power stations.”