Jun. 28--As the Rock-Tenn Co. ponders a future without steam- produced power for its St. Paul paperboard mill, officials are beginning to explore renewable energy technologies -- including fuel derived from household garbage.

Plant representatives have been visiting neighborhood groups to inform them of long-term energy alternatives that would help keep one of the city's oldest, largest and highest-paying employers operating in St. Paul.

But the prospect of a garbage burner on the 42-acre Midway site worries at least one Twin Cities environmental group that has been working with Rock-Tenn to educate communities about the potential project. The head of Minneapolis-based Eureka Recycling said she is just as interested as anyone in preserving the paper-recycling plant, whose local roots as Hoerner Waldorf go back more than a century.

"We just want to make sure there's a clean energy alternative," said Susan Hubbard, Eureka's CEO.

"The community is not going to support burning garbage in their neighborhoods."

The plant's uncertain future is tied to an ecological milestone for St. Paul: the upcoming conversion of the High Bridge power plant from coal to cleaner natural gas.

For decades, the High Bridge energy plant provided steam that Rock-Tenn converted into power. But that supply will cease next year as Xcel prepares for the new generating station.

Rock-Tenn plant general manager Jack Greenshields refers to the unknown fate of his Vandalia Street facility as an "unintended consequence of good public policy."

An onsite backup power plant could provide energy to the paper mill in the short term. But for the long haul, Rock-Tenn is looking to power the plant with a combination of biomass -- which typically refers to the incineration of plant materials and wood waste -- and refuse-derived fuel, or RDF.

The new alternatives would face an extensive review process known as an environmental impact statement, Greenshields said.

City and Ramsey County officials stress that RDF does not employ the same technology as the controversial Hennepin County mass garbage burner in Minneapolis. Mass-burn facilities typically process raw waste without sorting or shredding.

At RDF facilities, such as a Newport center jointly operated by Ramsey and Washington counties, separators and shredders take out metals and other noncombustible materials before processing. Then the processed waste is hauled off to combustion facilities that convert the trash into energy.

Still, both methods of incineration produce emissions, said Zack Hansen, manager of the county's Environmental Health Section. Their effect on air quality largely depends on the kind of fuel used, the technologies involved in the burning and the handling of the emissions, Hansen said.

The city, Ramsey County and the St. Paul Port Authority have been monitoring Rock-Tenn's plans and cite the need to balance environmental concerns with sound investment choices.

"St. Paul cannot become a community of just coffeehouses and condos," said Anne Hunt, the city's sustainability coordinator and deputy policy director for Mayor Chris Coleman. "Rock-Tenn has good- paying jobs."

The situation also presents an opportunity to save a longstanding recycler and better manage the county's solid waste. Georgia-based Rock-Tenn employs more than 500 people at its St. Paul plant, which uses recycled paper to make cardboard.

The Port Authority is considering whether to finance, build and own a new power plant on the Rock-Tenn campus, said Lorrie Louder, director of industrial development. It's possible that the power plant could sell energy to other businesses on the western end of University Avenue, similarly to the shared district energy system in downtown St. Paul.

"We are looking for every creative form of financing we can find," Louder said.

A new plant could cost more than $120 million. Rock-Tenn still needs to study which energy sources would be viable and whether they'd be available long term, Greenshields said.

Eureka Recycling is hoping Rock-Tenn will commit to the highest possible percentage of "clean biomass," Hubbard said. She also thinks incinerating garbage is the wrong approach to take at a time when people should focus on reducing consumption and recycling.

Nina Axelson, environmental coordinator for the St. Anthony Park Community Council, said her group needs to sort out the complexities of the issue before taking a position.

Axelson said they wanted to know more about a new plant's effect on the environment and health of the neighbors. But they also "have concerns about losing 500 jobs with a business that's been a good neighbor," she said.

Laura Yuen can be reached at lyuen@pioneerpress.com or 651-228- 5498.