If Tim Toben has his way, some Chapel Hill residents could soon be waking up beneath grass-covered rooftops in terraced nine-story towers angled specially to soak up the solar heat. They'll take showers using water warmed by the sun's rays and be able to dash downstairs to pick up a half-gallon of organic milk for breakfast.

On a spot along Rosemary Street now occupied by an Ethiopian restaurant, a few aging dwellings and a building used as a church, former KnowledgeBase Marketing Inc. CEO and environmentalist Toben and a group of residents interested in sustainability are proposing a $30 million "green building" project. They submitted initial plans for the 180,000-square-foot "Greenbridge" to the town this month.

Toben has hired one of the leaders of the sustainable building movement, Charlottesville, Va., architect William McDonough, to design it. His firm designed an eco-friendly 195,000-square-foot corporate campus for Gap Inc. in San Bruno, Calif., covered 10 acres of rooftop with vegetation at a Ford Motor Co. plant in Dearborn, Mich., and has been hired to design seven entirely new cities in China. He has been proclaimed a "Hero for the Planet" by Time magazine.

Landscaped roofs

Toben serves on the boards of N.C. Environmental Defense and the Carolina Environmental Program at UNC-Chapel Hill, runs an organic farm and drives a biodiesel-powered Jetta. He met McDonough three years ago when the architect was in town for a lecture at Duke University.

McDonough later invited him on an Icelandic salmon fishing trip with other environmentalists. After hearing McDonough's vision for buildings that produce more energy than they consume and ecologically intelligent design, Toben decided that if he could put the land together, he'd launch a green building project in Chapel Hill. McDonough said he'd design it.

McDonough could not be reached for comment, but Toben said the architect wants to create a model for sustainable building in North Carolina.

The initial plans include two buildings, which would be nine stories at their highest and connected by a bridge. Toben said the buildings may need to be as high as 100 feet to maximize solar radiation, and that he could ask the town to waive its 90-foot height limit for that area.

The buildings would gain height as they recessed from the street, creating space for individual rooftop terraces covered with three to four inches of soil.

The landscaped roofs would soak up rainwater to reduce runoff, create oxygen through photosynthesis and provide a habitat for birds, Toben said.

Other design possibilities include moving water through panels so it can be warmed by the sun before trickling down through shower heads in condominiums below, and using a wheatgrass compound for countertops.

Toben said the development would have 100 to 120 condominiums -- he wouldn't give a price range -- with retailers that could include a small natural foods store, a restaurant that uses local, organically grown produce, or a shop that sells fair-trade items from around the world.

A third building would serve as an educational center, screening films about the site's history as part of Chapel Hill's black business district and its new role as a model for sustainable building.

Demand may rise

The project is the latest in a series of major residential developments downtown. Since 1999, residential and mixed-use projects have brought about 200 new residents downtown, and projects in the works could add 800 more.

Bill Bracey, owner of Arbor Realty near the site of the proposed project, and a former board member of the local Sierra Club, said that though there hasn't been a huge demand for green homes, he expects demand will go up as availability increases.

"That really hasn't been a choice; you've had to really go after it," Bracey said. "It's hard when someone is either building their own housing or workspace to justify a solar component. I suppose it's like hybrid cars; ... the more demand grows for them, the more economical they'll become."

The project is scheduled for review by the town's design committee, the first step in Chapel Hill's planning process, Jan. 24. Toben said he'd like to break ground on the project this time next year.