Coronavirus-induced supply-chain breakdowns in China have caused the developers of two large solar-power projects in Wisconsin to declare force majeure, threatening construction delays. And some Minnesota solar companies are wary that manufacturing bottlenecks could soon hurt them, too.

"I'm definitely concerned about it because a lot of solar-project components come from Asia," said David Amster-Olszewski, CEO of Denver-based SunShare, which is a significant developer of community solar projects in Minnesota. And delays aren't the only problem.

"Any interruption impacts pricing for the whole supply chain," he said.

Asia, and particularly China, is the globe's primary supplier of solar cells and panels, and is also a major source of inverters and racking system components. Racks hold solar panels in place; inverters convert panels' DC current into AC.

Also, about 80% of the specialty glass used to manufacture solar panels comes from China, said Martin Pochtaruk, president of Heliene, a solar-panel maker in Mountain Iron, Minn.

"We have glass now," he said. "But are [shipping] containers going to start being delayed? We don't know yet."

In a solar panel, the energy-producing cells are basically sandwiched between glass and a "backsheet" made of polymers. Heliene has a potential problem with the latter component, too.

The company primarily sources its backsheets from a factory in the Lombardy region of northern Italy, which is also suffering a coronavirus outbreak. Production has been temporarily disrupted there, too, though Heliene still has some backsheet inventory.

In all, more than 94,000 people have contracted the virus worldwide, according to the Associated Press. More than 3,200 people have died, including more than 10 in the U.S. It has caused havoc with the Chinese economy and has spread to more than 80 countries, with significant outbreaks in South Korea, Iran and Italy.

Two solar developers last week declared "force majeure" on solar farms under construction in southwest and northeast Wisconsin. Force Majeure — "superior force" in Latin — is a contract clause invoked when extraordinary circumstances from weather to war prevent a contractor from meeting its obligations.

NextEra Energy Engineering and Construction, an arm of one of the nation's largest solar developers, declared force majeure because of factory shutdowns and travel restrictions in China, the company said in a filing with the Wisconsin Public Service Commission.

The interruptions are "adversely impacting" the delivery of racking systems to be used at the Two Creeks solar project about 30 miles southeast of Green Bay. Florida-based NextEra believes the delay will impinge on its work at Two Creeks and will require an "adjustment to the Project schedule," according to a regulatory filing.

Chicago-based Invenergy, another large solar-power developer, declared force majeure on the Badger Hollow project near Montfort in southwestern Wisconsin. Invenergy said in a Wisconsin regulatory filing "there exists the potential for delays," and also cited travel restrictions and factory shutdowns in China.

Brendan Conway, a spokesman for the majority owner of the two solar projects, WEC Energy Group, said in an e-mail that construction on both continues. "It's too soon to say if international supply chain issues will cause any significant delays," WEC Energy Group said.

Two Creeks, which broke ground last summer, is Wisconsin's first large-scale solar project, with a planned 150 megawatts of capacity. Badger Hollow, a two-phase project that's also under construction, is even bigger with up to 300 megawatts.

By contrast, the largest solar farm in Minnesota is the 100-megawatt, 440,000-panel North Star project in Chisago County that supplies power to Xcel Energy. No other such large-scale "utility" solar projects are under construction.

But that's not the case for Minnesota's community solar gardens: small projects that usually produce up to one megawatt of power.

In January, Minnesota had around 150 community solar gardens either in the design or construction phase, according to a filing with the Minnesota Public Utilities Commission. The state already hosts around 270 community solar projects, which together provide more than 650 megawatts of power.

Xcel, which administers the state's community solar-garden program, said it has not heard of any construction delays because of coronavirus-induced supply-chain issues. A representative of a Minnesota trade group for the solar industry said the same. Still, worries about supply-chain failures are radiating through the industry.

"Obviously we are very concerned about coronavirus and we are getting initial reports of supply disruptions," said John Smirnow, vice president of market strategy and general counsel for the Solar Energy Industries Association, a national trade group.

"While those reports are limited in scope now, companies are making contingency plans and backup arrangements in the event of more significant disruptions."

Mike Hughlett • 612-673-7003