June 4 (Reuters) - Two of the world's biggest solar panel makers, First Solar and Hanwha Qcells, became the first to register products under an environmental ratings system preferred for U.S. government purchasing, an industry group said.

Combined, the companies have seven products that meet the EPEAT standard created by the Global Electronics Council, according to Qcells, the GEC and the Ultra Low-Carbon Solar Alliance, a solar industry group.

The Biden administration has established rules requiring federal buyers to maximize their use of sustainable products, defined as adhering to third-party standards outlined by the Environmental Protection Agency (EPA) late last year.

The EPEAT standard for solar panels was among those recommended by the agency. To achieve the EPEAT label, producers must meet criteria for efficient power and water use, recycled content, disclosure of substances used in manufacturing, worker health and safety and more.

Producing panels in the United States helps lower the carbon intensity of the products. Both First Solar and Qcells have U.S. manufacturing facilities.

The distinction will help First Solar and Qcells become go-to suppliers for federal projects, which are expected to be a major source of demand for solar panels. As part of his climate change agenda, President Joe Biden set a goal to decarbonize federal buildings by 2045, including a 50% reduction by 2032.

The administration earlier this year, for instance, said it would install solar panels on the Department of Defense's Pentagon headquarters in Virginia.

"The EPEAT ecolabel will make it easy for customers who value transparency and sustainability to find our products and work with us," Qcells' senior director of sustainability, Kelly Weger, said in a statement.

"Beyond commercial and residential customers, this now means our USA assembled and sustainably made solar products will help the federal government achieve its ambitious climate goals."

Several other manufacturers are in the process of getting their solar panels registered under the standard, according to Bob Mitchell, chief executive of the Global Electronics Council.

"With the growing demand from global purchasers for responsibly manufactured panels, we expect significant growth of participating companies in the coming months," Mitchell said. (Reporting by Nichola Groom; Editing by Stephern Coates)