These sisters watch over Mother Earth.

CLYDE, Mo. | At a century-old monastery atop a ridge in northwest Missouri, Sister Sean Douglas contemplates ground-source heat pumps. To retrofit the thick-walled home and chapel of the Benedictine Sisters of Perpetual Adoration for a geothermal system would be costly, she knows. But the existing radiator heat, fueled by propane, is so ? ?Awful,? Douglas said. Awful, she means, because it?s a nonrenewable resource.