Boston's Trinity Church begins renovations with drilling of geothermal wells

January 8, 2002

A significant building project at Trinity Church in Boston's Copley Square, designed to preserve, renovate and expand the church and the parish house, kicked off its first phase of construction on January 2 when work began on a series of six geothermal wells close to the church's exterior.

The wells are the heart of a new energy system designed to make it possible to renovate and use the church's undercroft--the space below the sanctuary, much of which currently remains a basement with a dirt floor. When completed it will provide the church with social space able to accommodate the parish's needs. The system will also support renovations planned for the parish house.

Trinity Church's plans are in keeping with resolutions adopted in 2000 by the Episcopal Church's General Convention and Massachusetts' Diocesan Convention, both encouraging the use of environmentally safe and sustainable energy sources.

Overseeing the work will be Trinity Church's architectural firm, Goody Clancy and Associates. The construction manager contractor is Shawmut Design and Construction. Shawmut, in turn, has contracted with a number of technical consultants, including A & W Artesian Wells.

The geothermal system will include six wells that make use of the constant temperature of the earth. The eight-inch-wide wells will be drilled into bedrock, up to 1,500 feet below the surface--twice the height of the nearby John Hancock Tower--and filled with water. That water remains somewhere between 50 and 55 degrees through the year, and can be circulated to cool a building in the summer and help to warm it in the winter.

The idea of geothermal exchange dates back to 1824. Geothermal systems were first developed in the United States half a century ago, and they have become widely popular more recently, in part because they are environmentally friendly.

The system uses no fossil fuel, produces no emissions, runs silently and, once completed, is invisible. The water in the well remains at equilibrium, an important issue in Boston's Back Bay where many buildings are built on wooden pilings that require an unchanging water table. It requires no cooling tower, and can be sized to fit a specific development or building.

Geothermal exchange systems today serve a wide range of building types and sizes in hundreds of installations. In aggregate, these systems deliver the energy equivalent of three traditional nuclear power generators, according to industry experts.

Although geothermal wells are well established nationally, it is unusual to find them in a dense urban setting because of the need for open space in which to do the drilling. That makes Trinity Church an ideal site for the project, because the open space around the building makes it possible to accommodate the necessary equipment.

Construction of the geothermal wells is expected to last for approximately six weeks. The church will remain open throughout the project with entrances from Copley Square as well as from Clarendon Street.

Because of the depth of the wells, the actual drilling will not be noisy. The engines that run the drilling rigs, however, have been described as sounding like city buses accelerating. Those engines will be muffled by wooden structures that are being installed to reduce the noise.

'We are doing this project now when use of Copley Square is at a minimum,' said Sarah Wilcox, associate for administration. 'One of our goals is to be a good neighbor, which is why we are doubling up the drilling to get done as quickly as possible.'