The Energy Department said on Thursday that it planned to offer $22.9 billion in loan guarantees to help eight electric utilities around the country modernize their power grids, add large amounts of renewable energy — and pass along any resulting savings to customers.

The deals amount to one of the biggest commitments ever made by the department’s Loan Programs Office, which under President Biden has already doled out tens of billions of dollars for battery factories and other low-carbon energy projects.

As part of the 2022 Inflation Reduction Act, Democrats in Congress handed the office $250 billion in loan authority to repurpose or replace existing energy infrastructure in order to lower air pollution and reduce planet-warming emissions. So far, the office has used that authority to back efforts to restart a shuttered nuclear reactor in Michigan and to help California’s largest utility upgrade its electric grid.

The new loan guarantees, which still have to be finalized, are even more far-reaching. They are meant to help utilities that serve more than 14.7 million people across 12 states upgrade aging transmission lines or build new ones. Doing so, the office said, would help power companies tap into more wind, solar and hydroelectric power while improving grid reliability.

In Michigan, DTE Electric and DTE Gas would receive loan guarantees totaling nearly $9 billion to install thousands of megawatts of solar, wind and batteries and to replace existing gas pipelines in order to reduce leaks of methane, a potent greenhouse gas.

In the Pacific Northwest, PacifiCorp would receive a $3.52 billion loan guarantee to help build 700 miles of new transmission lines in Idaho, Oregon and Utah, with the aim of using more renewable energy and cutting emissions.