Microsoft pays for capturing carbon from burning wood

Microsoft just backed a major plan to capture the CO2 emissions from a wood-burning power plant. Today, the technology giant announced a deal with Danish energy company Ørsted to buy credits representing 2.76 million tonnes of carbon dioxide captured over 11 years at Ørsted’s Asnæs power station.

According to a Ørsted press release, it is one of the largest deals a company has made to date to reduce carbon dioxide emissions. The move should help Microsoft meet its goal of becoming carbon negative by 2030, the point at which the company removes more carbon dioxide from the atmosphere that warms the planet than it generates through its operations.

It is one of the largest deals a company has made to date to reduce carbon dioxide emissions

But the technology to mitigate carbon dioxide emissions is still in its infancy, and some environmental groups and researchers are skeptical whether the strategy Microsoft just helped fund could be an effective way to tackle climate change. Without Microsoft’s support, Ørsted would not have been able to install carbon capture devices at its power plant. “Danish state grants and the contract from Microsoft were both necessary to make this project viable,” said Ørsted’s announcement.

With the help of Microsoft, Ørsted was able to secure an even bigger, 20-year contract with the Danish Energy Agency (DEA) to capture the CO2 emissions from Asnæs in western Zealand and a second power plant near Copenhagen. After the carbon capture devices are installed, they should be able to capture a total of 430,000 tons of CO2 per year by 2026. For comparison, that is roughly equivalent to the amount of CO2 emitted by a single gas-fired power station in a year.

However, these power plants burn wood chips and straw, fuels also known as ‘biomass’. And burning biomass, including agricultural waste and other plant material, as a sustainable energy source is controversial. The EU considers biomass to be the largest source of renewable energy, but much of the wood burned comes from trees felled in forests across Europe and the southeastern US. Ørsted says the wood chips burned at the Asnæs Power Station “come from sustainably managed production forests and consist of the remains of pruned or crooked trees.”

How should burning trees be good for the environment?

How should burning trees be good for the environment? After all, wood still gives off CO2 when burned. The argument is that trees or crops used to make biomass naturally absorb and store CO2 when they are alive. So if you replant the trees or plants, you may have a fuel that is carbon neutral.

Ørsted goes one step further by adding technologies that can filter CO2 from the chimneys of its power plants, preventing it from being released into the atmosphere. By doing so, it believes its biomass plants will become carbon negative. They plan to bury the excess carbon dioxide they capture under the North Sea and sell credits to Microsoft representing every ton of CO2. Microsoft can then use those credits to claim that it has eliminated some of its own greenhouse gas pollution.

If all that sounds like a tricky balancing act, it is. Previous research has shown that burning woody biomass can cause more CO2 emissions than it captures. That’s because just capturing chimney emissions doesn’t account for all the pollution that could be created from cutting down the trees and transporting the wood. In addition, it can take a long time for trees or plants to mature enough for people to be confident that they absorb a significant amount of CO2.

“We think the details are critical,” Phillip Goodman, portfolio director of carbon removal at Microsoft, said in an email to The edge. An effective carbon capture project should use biomass “harvested from appropriate areas” and account for all “process” emissions, Goodman says. Microsoft declined to say how much it would pay Ørsted for carbon removal credits for this particular project.

Microsoft has been making bold bets on climate technology and clean energy technologies lately. Last week it announced a plan to buy electricity from an upcoming nuclear fusion power plant — even though some experts don’t think such a sophisticated power plant could realistically be developed for decades to come. Microsoft also paid a Swiss company called Climeworks to filter CO2 from the air.

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