In January, Treehugger profiled a gym in Detroit that’s available for use by the homeless and has electricity-generating equipment. According to Cass Community Social Services, “The gym will be open daily for homeless people living in the CCSS’s transitional housing and permanent supportive housing programs, as well as staff members and volunteers.” The gym uses energy-harvesting stationary bikes made by Green Revolution.

I became aware of Green Revolution right after The Human-Powered Home was published, and I haven’t had the pleasure of talking with the folks there. But according to the article, their technology “can be installed on most brands of indoor cycling equipment. At its retrofit gym in Ridgefield, Connecticut, a typical cycling class with 20 bikes has the potential to produce up to 3.6 Megawatts (3,600,000 watts) of renewable energy a year. This is equivalent to lighting 72 homes for a month, and reduces carbon emissions by over 5,000 pounds.” (Note the word “potential” — does that mean if the bikes were constantly in use? By elite athletes? Or everyday exercisers?)

Also according to the Treehugger article, “One year of four daily classes, Cass projects that full classes of 10 have the potential to provide enough power to light three homes for a year–all of which will be redirected back to the facility’s power grid, reducing its operating costs.” That estimate seems high to me, but I suppose it depends on how many lights those homes have.