If you thought faring worse than an industry pummeled by a once-in-a-century global health emergency was impossible, check out what’s been happening to renewable energy stocks.

Successive flare ups of the pandemic have dealt repeated blows to hopes for a revival of flying and tourism. Travel and leisure was the worst-performing sector in the Europe Stoxx 600 index this year, missing out on the rally that catapulted equities across the region to successive records.

And yet airlines have actually outperformed green stocks in 2021, despite this year’s pledges by governments to cut greenhouse emissions and invest heavily in clean energy. A gauge of the largest and most liquid European stocks in the renewable energy sector is down 20% in 2021, just as the Stoxx 600 ends the year hovering around record highs.

Deutsche Lufthansa AG has shed about a fifth of its value this year, while British Airways owner International Consolidated Airlines Group is down 12%. Disappointing as they may look, such returns look stellar compared to plunges of 37% for Siemens Gamesa Renewable Energy, and 33% for offshore wind farm champion Orsted A/S.

After dropping by nearly a third this year, Vestas Wind Systems has warned that more pain lies ahead, amid surging commodity prices and supply-chain bottlenecks that disrupted production. But the cost of raw materials is not the only reason blamed for the lackluster returns.

In a way, green stocks are paying the price of past success, as a rally in 2019 and 2020 catapulted their valuations into the stratosphere. Now, much of the good news on government pledges to pivot their economies toward a low-carbon model is already priced in.

Even after this year’s share price plunge, Siemens Gamesa trades at 52 times its expected earnings for next year, and Vestas at 45 times. That compares to 15.7 times for the Stoxx 600.

While equity strategists from BlackRock Inc. to Goldman Sachs Group Inc. and Societe Generale have said that decarbonization presents unprecedented opportunities to investors, near term headwinds remain.

Valuations for “green stocks are still elevated,” Bloomberg Intelligence strategists Tim Craighead and Laurent Douillet said in a note. “Lower sales expectations and higher steel prices pressure wind-turbine profits.”