Microsoft signed a deal to remove to permanently remove 3.3 million metric tons of carbon dioxide with Swedish energy company Stockholm Exergi, the companies announced on Monday.

The contract with Microsoft is the world’s largest carbon removal deal to date, Stockholm Exergi said in a statement. Delivery of the carbon removal certificates to Microsoft are planned to begin in 2028 and will continue for a decade, according to Stockholm Exergi.

The Swedish company, which provides power to the people of Stockholm, plans to build a carbon capture and storage project that will permanently remove 800,000 metric tons of carbon dioxide per year.

Construction on the carbon capture project is scheduled to start in 2025. The contract with Microsoft will help the project move closer to a final investment decision in the fourth quarter of this year, said Anders Egelrud, the CEO of Stockholm Exergi, in the statement.

The carbon capture project will be installed at Stockholm Exergi’s biomass power plant, which is the largest of its kind in Europe. The plant burns waste from the forestry industry and paper mills to produce heat and electricity.

Carbon dioxide released from those materials during incineration will be removed from the gas emitted from the plant, liquified for transport and permanently stored underground.

Stockholm Exergi is selling carbon removal certificates, equivalent to 1 million metric tons of carbon dioxide, to help companies achieve their net-zero emissions goals.

“Leveraging existing biomass power plants is a crucial first step to building worldwide carbon removal capacity,” said Brian Marrs, Microsoft’s senior director of energy and carbon removal, in a statement.