Xcel Energy is facing fresh allegations that it is impeding the rollout of solar power in its Minnesota service region.

Two solar energy companies and the state Commerce Department separately have asked Minnesota utility regulators to jump start the community solar program ordered by a 2013 state law. It allows Xcel customers to subscribe to electricity from centrally located "solar gardens" built by independent energy companies.

Minneapolis-based Xcel, which is reviewing more than 1,100 applications from solar developers since December, has authorized just one community solar garden to connect with the distribution grid.

"The continuing delays and issues with this program are really impacting Minnesota's seeming leadership role in renewable energy," said David Amster-Olszewski, CEO and founder of SunShare, a Colorado-based pioneer in community solar that on Thursday asked Minnesota regulators to investigate Xcel for actions that delayed its intended $70 million solar garden investment this year.

Sunrise Energy Ventures, a Minnetonka-based solar developer, also challenged Xcel's handling of the program in a separate regulatory filing on Wednesday. SunShare and Sunrise each have submitted plans to build 100 megawatts of solar gardens that collectively would serve more than 30,000 Xcel customers.

SunShare asked the Minnesota Public Utilities Commission to investigate 100 cases in which Xcel allegedly violated program rules by not completing engineering reviews for solar projects on time or in sufficient detail. SunShare, an early entrant in the program whose projects are among the first to be reviewed, didn't accuse Xcel of dragging its feet, but said the utility hasn't put enough staff and resources on the job.

Sunrise Energy, which is developing solar gardens for Solar City, the nation's largest solar provider, attacked Xcel more harshly, saying its handling of the process "can charitably be described as a travesty." Sunrise asked that an administrative judge be appointed to resolve connection disputes with Xcel and urged the commission to reverse its June decision to limit solar garden projects to clusters of five by a single company in any location.

"Xcel only wants to do solar that they control completely," said Dean Leischow, managing director of Sunrise Energy, in an interview. "They don't like community solar … I believe they see it as retail competition and they just don't want to do it."

But reopening the regulatory process also could mean further delay and uncertainty about solar gardens at a time when companies are trying to sell subscriptions to customers.

"We need this regulatory process behind us — opening it back up doesn't do any good," said Martin Morud, founder and president of TruNorth Solar, an Edina-based company that signed the settlement with Xcel in June to limit solar garden clusters.

In a statement, Laura McCarten, Xcel Energy regional vice president, said the company is disappointed that companies are raising issues that had been considered earlier. "Xcel Energy's focus is now on implementing the program as it was approved and moving the process forward as the commission considers these requests," she said in an e-mail.

Sunrise had proposed up to 50 solar gardens in a single location, including a site near Monticello, Minn. It was the hardest hit when the commission in June agreed with Xcel and some smaller solar garden developers to the size limit.

Now, Leischow said, Xcel won't allow the company to shift solar projects to new sites without losing its place in the review queue, putting its projects behind hundreds of others. "The back of the line is a death sentence," he said.

Leischow also said Xcel has declared it won't connect a developer's solar gardens if the cost at a single location for upgraded power lines or substation equipment exceeds $1 million — even though that cost must be borne by the solar developers.

The Commerce Department, in a separate regulatory filing, asked the PUC to clarify whether Xcel is permitted to impose that and other conditions. But the department didn't accuse Xcel of wrongdoing.

The concerns about Xcel come five weeks after the owners of Louis Industries, a Paynesville, Minn., metal fabrication factory, complained that the utility delayed the hookup of its large rooftop solar array installed late in 2014. But that issue seems close to being resolved amicably.

Xcel, which denied causing delay, soon plans to hook up a new transformer needed for the project, said Ralph Jacobson, CEO of Innovative Power Systems, which installed the project.

But a final piece of equipment, which is the installer's responsibility, not Xcel's, remains on order until late September, Jacobson said.