A solar power installation on a bluff overlooking the Mississippi River has yet to materialize, four years after officials announced ambitious plans to build a 6-acre solar array that would power the Highland Bridge development in St. Paul.

Highland Bridge developer Ryan Cos. says the 1-megawatt solar farm has been slowed by a state regulatory review, but it's still in the works. Meanwhile, the company is pushing ahead with other projects designed to make Highland Bridge, on the former Ford Motor Co. assembly site, the greenest neighborhood in St. Paul.

Two buildings — Highland Bridge Medical Office and the Collection, a mixed-use building with apartments and commercial space — have achieved Leadership in Energy and Environmental Design (LEED) certifications. Another building, the Marvella senior housing building, is under final LEED review.

Lindsey Kieffaber, senior design project manager at Ryan, said LEED certification relies on a number of factors, such as restoration of habitat, water conservation and stormwater collection, energy conservation, building materials and waste reduction.

"It's impressive, and it's a big deal," she said, noting that the site's energy efficiency means less strain on the electric grid. Safer building materials means improved indoor air quality that helps people with conditions like asthma.

Russ Stark, who leads St. Paul's climate work as the city's chief resilience officer, said Highland Bridge is leading the way in sustainable development. The site treats stormwater by filtering it and diverting into a streamlike water feature. Several buildings already have rooftop solar panels.

Combined with the Heights, the 112-acre former Hillcrest Golf Course now being prepared for redevelopment on the East Side, Stark said the city will soon have two major redevelopments reducing reliance on fossil fuels.

"I think what they've done is really significant, actually," Stark said. "It's not often a city gets to do it at this scale. The ways we have been able to push the envelope on sustainability will be really impactful."

Stark said the large solar array, a partnership with Xcel Energy, is still planned to go on top of a massive concrete cap in what's known as Area C. The state first wants to make sure it understands the extent of pollution there, he said. The 22-acre site that sits between the Ford site and the Mississippi River to the west was used for decades to dispose of unknown quantities of paint, sludge and solvents. Ford still owns Area C, officials said.

When officials announced plans for the solar array in June 2020, they said electricity generated there combined with the 18 megawatts produced by the nearby hydroelectric plant means Highland Bridge will produce enough power for homes and buildings on its 122 acres and thousands of other homes and businesses throughout the area as well. Officials said that even when fully built-out, Highland Bridge is expected to consume no more than 5 megawatts.

In a statement, Ryan Cos. said: "Ryan and Xcel Energy are continuing to work with stakeholders on the implementation of the Corrective Action Plan for the site that will house the future 1MW solar array. We anticipate advancement in the coming months followed by applications to the Public Utilities Commission. The local, 1MW solar array will complement the on-site rooftop solar that has and will be installed on buildings within the Highland Bridge development."

Xcel officials issued a statement Friday night: "We're committed to continuing to work with Ryan Companies and doing everything we can to facilitate and support the sustainability goals at Highland Bridge. Putting a solar array on Area C ... involves numerous stakeholders. We continue to work with all stakeholders to determine the best use of this area."

Tim Morehead, a 28-year resident of Highland Park and a board member of the Highland District Council, said there is much to like about the sustainability plans at Highland Bridge. But the 74-year-old retiree with 11 grandkids said he continues to push Ryan officials to use even more stringent building and energy-use standards at the site.

"I have had many meetings with Ryan to say I am concerned with the future of the next generations," Morehead said. "Are the certifications for LEED good enough? We have to spend the limited resources we have correctly. We don't have a lot of time to make it better."