In June, US solar manufacturer Qcells became the second company in the world to register its solar panels with EPEAT, a labeling system that sets sustainability standards for electronics manufacturers. In doing so, the company has set in motion an obscure regulation requiring federal agencies to purchase EPEAT-certified solar panels. For example, if NASA wants to build a solar farm to power a research facility, it must now purchase panels that meet EPEAT’s stringent sustainability requirements – including a unique cap on CO2 emissions associated with solar energy production .

There’s just one problem: Although EPEAT launched its solar energy standards in 2019, there are currently only six EPEAT-registered solar panels on the global market. And there are currently no EPEAT-registered solar inverters, devices that convert the direct current produced by a solar panel into alternating current, which the grid uses. That doesn’t leave many choices for the federal government, or anyone else looking to buy sustainably produced solar equipment.

That’s why the Department of Energy (DOE) launched a new award in October that offers up to $450,000 to US-based solar panel and inverter manufacturers who achieve EPEAT certification for their products. As a new wave of domestic solar production kicks into high gear, the DOE hopes the award will ensure companies use efficient processes, sustainable materials, fair labor practices and low-carbon energy.

“The fact is that not all solar products are created equal,” says Patty Dillon, vice president at the Global Electronics Council, the nonprofit sustainable technology organization that administers the EPEAT eco-label.

Solar panels convert the sun’s rays into electricity in a process that does not emit radiation greenhouse gasesmaking them essential in the fight against climate change. To reach net-zero emissions by 2050, the International Energy Agency estimates that the world will need to add 630 gigawatts of new solar power annually by 2030 – an increase from the 135 gigawatts installed in 2020.

But some solar panels are more climate-friendly than others. Polysilicon, which is used to make the solar cells in silicon panels, is made using an energy-intensive process that is often powered by fossil fuels. The frames that hold the solar panels together are made of aluminum, which is typically melted in China using electricity from coal. The manufacturing processes that turn these materials into a solar panel also require energy, which can lead to more emissions. At a global level, the difference between solar panels made using clean energy and those made with fossil fuels could amount to tens of billions of tons of carbon pollution by the mid-21st century.

To minimize these emissions, along with other environmental challenges such as the use of toxic chemicals and the disposal of e-waste from solar energy, companies must take a hard look at their supply chains and, in some cases, undertake difficult cleanup efforts. The DOE’s new award, “Promoting Registration of Inverters and Modules with Ecolabel,” or PRIME, encourages companies to do this by going through the EPEAT registration process.

“EPEAT certification allows companies to demonstrate how they have taken steps to achieve more environmentally friendly supply chains and manufacturing processes,” Becca Jones-Albertus, who leads the DOE Office of Solar Energy Technologies, told Grist.

Solar companies seeking EPEAT registration must meet a list of criteria covering four broad themes: climate change, sustainable use of resources, hazardous chemicals and responsible supply chains. Depending on how many standards a manufacturer meets, it can receive an EPEAT Bronze, Silver or Gold designation.

In addition, from June, solar manufacturers registered with EPEAT must meet the industry’s first-ever criteria for embodied carbon, the emissions generated when a product is produced. For every kilowatt of electricity produced, no more than 630 kilograms of CO2 may be emitted during the production of an EPEAT-registered solar panel. The limit, Dillon says, represents about 25 percent less CO2 emissions than the global average. Solar panels that fall below the ‘ultra low carbon’ threshold of 400 kilograms of CO2 per kilowatt of power earn a special EPEAT Climate+ designation.

“That actually represents best in class,” Dillon said.

It is difficult to make a direct comparison with fossil fuel power plants because most of their emissions come from operational activities and not from building infrastructure. But other research has found that solar power plants are significantly more climate-friendly over their lifetime, emitting about 50 grams of CO2 per kilowatt hour of energy produced, compared to about 1,000 grams per kilowatt hour for coal.

Meeting EPEAT’s requirements isn’t easy, which could explain why only two companies – QCells and Arizona-based First Solar – are currently on the register. And only two solar panels produced by First Solar have earned the ecolabel’s Climate+ badge. QCells, which produces two EPEAT-registered panels at a factory in Dalton, Georgia, spent about two years going through a “very extensive” certification process that involved collecting data from across its supply chain and subjecting it to a third-party audit, head of corporate communications Debra DeShong told it to Grist.

“It’s not an easy task,” DeShong said. “It requires resources and it requires a will.”

Other companies may now be motivated to try. QCells’ additions to the EPEAT registry in June triggered the Federal Acquisition Regulation, which requires the federal government to purchase goods that meet U.S. Environmental Protection Agency standards, except in limited circumstances where it is impractical to do so. In the case of solar panels, this means EPEAT-registered products. The DOE’s PRIME award, which provides U.S. solar manufacturers $50,000 for starting the registration process and up to $100,000 per product for up to four products that complete the registration process, provides an additional incentive. Jones-Albertus told Grist that the award was intended to “roughly offset the cost of collecting all the data and going through the registration process.”

Solar companies “told us they are interested in EPEAT certification, but they are not there yet,” Jones-Albertus said. “We hope to provide incentives to help companies move through the EPEAT registration process more quickly.”

Companies looking deep into their supply chains for the first time may discover that they need to make some changes to comply with EPEAT registration requirements. To reduce the carbon footprint of its panels, a solar manufacturer may need to switch to a low-carbon polysilicon supplier. (QCells, for example, buys polysilicon from a plant in Washington state that produces the stuff using hydropower.) Or it could decide to replace foreign-made virgin aluminum frames with recycled steel frames built domestically by Origami Solar, a change that reduces CO2 emissions linked to the frame by more than 90 percent. To meet EPEAT’s optional recycled content criteria, a manufacturer might decide to purchase recycled panel glass from a company like SolarCycle.

Implementing these types of changes in the production chain takes more time and money than what the new DOE price will yield. But Dillon of the Global Electronics Council is optimistic that more companies will register their products with EPEAT now that federal buyers require it.

Erik Petersen, the chief strategy officer at Origami Solar, believes the Biden administration’s push for clean domestic manufacturing, combined with growing consumer interest in supply chain transparency, will push more U.S. solar companies to ensure that their products meet high sustainability standards.

“What’s exciting is that all these forces are coming together at the same time,” Petersen told Grist. “That really gives the industry an incentive to do the right things.”