New York Times
By Alison Gregor
Advocates for geothermal energy say that the path of destruction cut by Hurricane Sandy, which unearthed fuel tanks, ravaged cooling towers and battered air-conditioners, has already persuaded some building owners to switch to geothermal systems that use underground pipes to harness the earth’s energy for heating and cooling buildings.
“We’re seeing dozens of these half-empty and empty oil tanks just popping up all over the place in the flooded areas,” said David E. Reardon, the manager of geothermal drilling for the Miller Environmental Group, an environmental response, remediation and restoration services company based in Calverton on Long Island that has been involved in poststorm environmental cleanup throughout the region.
“Those tanks become buoyant in all that water,” he said. But since geothermal systems don’t use fossil fuels or mechanical systems that are exposed to the elements, Mr. Reardon said, he started fielding calls from people asking for estimates on geothermal systems just days after the storm. “Often it’s a case where they were considering doing it, but were waiting for something to finally no longer be able to be repaired,” he said, and the storm has ended that wait.
Geothermal energy systems, common in countries like Iceland and China, use the constant temperature of the earth to heat and cool buildings.
Geothermal wells are dug to a depth where the earth regulates the temperature of water or a liquid circulating through the system. Geothermal systems may require one well or dozens to regulate a building’s temperature, depending on the size of a building and type of system installed. While the systems are called wells, they are actually an underground network of pipes connected to heat pumps to circulate water or some other liquid.
Because digging geothermal wells can be expensive and logistically difficult, the systems have been slow to catch on in New York City. Yet, according to the Rockefeller Foundation and DB Climate Change Advisors, “buildings consume approximately 40 percent of the world’s primary energy and are responsible for 40 percent of global carbon emissions,” said Jack DiEnna, the executive director of the Geothermal Heat Pump National and International Initiative, based in Washington.
Installing a geothermal system can significantly reduce a building’s carbon footprint, and over the last decade, the number of geothermal heat pump systems in the city has grown steadily. More geothermal systems are installed in New York, New Jersey and Pennsylvania than anywhere else in the United States.
Most systems are being installed in institutional buildings, multifamily residential buildings and relatively small commercial buildings. There have been systems installed by several prominent organizations and sites in the city, including the American Institute of Architects, the Times Square TKTS Booth, the Brooklyn Children’s Museum, the Queens Botanical Garden and the Bronx Zoo Lion House. In some of the outer boroughs and the suburbs, geothermal systems for single-family homes are also becoming more popular.
In all, more than 100 geothermal projects are in operation in the five boroughs, and about 90 percent of those projects are what are known as closed loop vertical bore systems, Mr. DiEnna said. A closed loop system is sealed from the ground and liquids are reused within the system, while an open loop system has discharge water it releases into a ground well or surface water.
Because building sites in the city, particularly Manhattan, tend to be small, the wells tend to be vertical, just like the buildings. Manhattan is not an ideal location for geothermal heat pump systems, because the wells must go so deep — to depths of roughly 1,500 feet — to reach the volume of land necessary to provide a constant temperature. In other areas with more available land, a geothermal heat pump system can be more spread out and much shallower, making it less costly to dig.
Elsewhere, larger scale geothermal projects known as enhanced geothermal systems have raised serious concerns because these larger power-production projects involve drilling wells down to tens of thousands of feet and fracturing the bedrock so water can be injected to create steam.
A few years ago, a project in Switzerland was shut down after it caused small earthquakes, and another project in Northern California was also stopped because of similar concerns. But the static, small-scale geothermal heat pump systems installed in the New York area bear little relation to these projects, said Daniel P. Schrag, a professor of geology and director of the Center for the Environment at Harvard.
“These are a totally different thing,” he said. “These are very shallow systems that don’t involve pumping huge volumes of water in, creating steam and fracturing the rock.”
Even so, to help maintain the geological integrity of the earth, most municipalities closely regulate well drilling, especially for wells dug below 500 feet, Mr. DiEnna said. “Manhattan is not the most ideal space for geothermal,” he said. “But the other four boroughs offer many opportunities to install this renewable technology.”
In New York, “the biggest obstacle currently to geothermal energy is the initial cost, which can be more significant than a traditional furnace replacement,” said Daniel Goodwin, a mechanical engineer with the Miller Environmental Group. However, Mr. Goodwin pointed out that since geothermal systems both heat and cool, they can replace not just the heating system but the cooling system as well.
It makes the most sense to install a geothermal system in new construction, especially given state incentives and federal tax credits for geothermal, he said. “If you’re retrofitting a building, it’s going to be an initial cost,” Mr. Goodwin said. “But from a new construction standpoint, when you look at the numbers and the tax credits and things out there, it really becomes a no-brainer.”
But even a retrofit can quickly make economic sense. At the Brooklyn Children’s Museum, an open loop geothermal system with four wells was installed in 2007 at a cost of $675,000.
That initial cost was hefty, but is being offset by savings on energy costs. The museum was initially paying $200,000 annually for heating, cooling and electricity in its 50,000-square-foot building with conventional methods.
With the installation of the geothermal system, it was able to expand to 110,000 square feet and provide energy to the additional 60,000 square feet for only $50,000 more. Donald Cramer, the museum’s chief operating and finance officer, called the geothermal system “very successful and extremely efficient.”
The New York chapter of the American Institute of Architects was an even earlier adopter of geothermal technology at the Center for Architecture in Greenwich Village. The center wanted to retrofit the existing building with a system using alternative renewable energy and chose geothermal, said Rick Bell, the center’s executive director.
A two-well system took three weeks to drill — closing down three of LaGuardia Place’s four lanes — to a depth of 1,260 feet in 2003 at a cost of about $100,000, he said.
The center’s needs were primarily for cooling, and installing a cooling tower on its roof would have cost about $60,000, he said. Though the center’s administrators felt that the additional $40,000 for geothermal was justifiable, they sought and received financial assistance from the New York State Energy Research and Development Authority, which has programs to encourage the use of alternative energy technologies.
“In other cities, geothermal is not a radical, what-were-they-thinking kind of technology, but something that’s very common,” Mr. Bell said. “We said we can research those places.“
The authority eventually pitched in about $85,000 toward the 65-ton closed loop geothermal heat pump system, Mr. Bell said. But the Center for Architecture has determined that, even without that assistance, it would have moved forward because the geothermal system was projected to pay for itself in less than three years, he said.
A geothermal heat pump system, if installed correctly, can cut the annual energy bill of a building by 30 to 60 percent, said Zoe Reich, an environmental specialist who heads the sustainability department at the engineering firm Edwards & Zuck. The typical payback period for geothermal systems in New York is two to eight years, factoring in any financial incentives or tax credits, Ms. Reich said.
“That’s quite a large span, but it does depend on how efficient your system is running and making sure you chose the right system for the geology of your location,” she said. “One very important aspect is working with a hydrogeologist to determine the best system for your location.”
If the proper system is installed, then not only does it save money in operations, but also in maintenance, Mr. Goodwin said. “Since there’s no combustion, there’s no carbon fouling due to the burning of fossil fuels, it’s easy to maintain,” he said.
Also, the pipes in a closed loop vertical bore well system are warranted for 50 years, while the aboveground geothermal equipment has a life expectancy of 25 to 30 years, Mr. Goodwin said. That’s roughly twice the life expectancy of a furnace or other conventional system, he said.
In Manhattan, the deep bore wells needed can cost anywhere from $125,000 to $150,000 a well. For a 500-unit multifamily building, for example, 10 to 15 wells would be needed, making the cost as much as $2.25 million, said Matt Donolli, a managing partner at Edwards & Zuck.
Single-family homeowners, except possibly those in high-density areas like Manhattan, would not have to spend that much on their shallower wells, he said. A 3,000-square-foot home in a more suburban area would probably need two to three wells, at only $9,000 per well, as part of a geothermal heat pump system to heat and cool the home.