Renovations of the 19 historic buildings of General Theological Seminary in New York City include a changeover to geothermal heating and cooling. The $100 million upgrade project includes a green master plan. Each of the landmark buildings of the country’s oldest Episcopal seminary will have a geothermal well sunk 1,500 feet to water at a year-round temperature of 50-60 degrees. When completed, the energy switch will allow the disconnection of two large gas and oil-run boilers, eliminating 1,400 tons of carbon emissions annually. “The economic payoff won’t come for a decade,” said Dean Ward Ewing, “but it’s the right thing to do for the earth.”