A proposal to install 600 kilowatts of solar-powered electrical generating panels atop the Minneapolis Convention Center won a key round of approval at City Hall on Thursday.

Developer Best Power International heads a team that would install the project. It would be 50 percent larger than a photovoltaic system the company switched on last month at St. John's Abbey in central Minnesota.

A City Council panel voted Thursday to recommend Best Power be named the preferred developer by the full council on Jan. 29.

The proposed solar generating system is expected to cover about half of the convention site's roof, none of it on the center's signature domes. It would produce at least 5 percent of the facility's annual power needs, according to a presentation to the council. The 2,600 panels, which would be installed on the flat portion of the center's roof, wouldn't be visible from street level, the city said.

If the full council approves the project Jan. 29, the city and Best Power still will need to clear two hurdles before the project can go ahead this summer.

First, they need to formalize an agreement, for which final negotiations would begin after council approves. Then they would need approval from state regulators to shift a $2 million renewable energy grant to the city to subsidize the deal.

The grant is a factor because this marks the second time the city has tried working with a developer on solar power for the Convention Center roof. The council voted last summer to pull out of a proposed deal with a Colorado-based solar developer after failing to reach agreement on terms. Because the grant earlier was designated for the city and that developer, the city is asking an advisory board and the Public Utilities Commission to shift the grant to the city. The board signaled it is open to doing so by approving the city's move to seek new proposals from developers.

The new deal represents vindication for Council Member Lisa Goodman, who had raised numerous questions about the experience and financing behind the Colorado developer, EyeOn Solar, and argued that the city could do better seeking competing proposals.

The city hasn't yet decided which of two models it would use for paying for the generated power. If it agrees to a flat 20-year price, estimates are that the city would initially pay $18,000 more annually for the generated electricity than it pays Xcel. But assuming that electrical rates rise 2 to 3 percent annually, the city would pay less after five to seven years for the solar power than if it bought from Xcel, according to Greg Goeke, the city's director of property services.

Another option would be a lower initial price that escalated during the life of the agreement, potentially front-loading any savings.

City officials hailed the outlines of the proposed agreement after outside attorney James Strommen told them it incorporates financial protections at key development milestones should the partnership collapse.

Steve Brandt • 612-673-4438