It took developer LCOR a stack of incentives to bring down the cost of a geothermal system it installed in a mixed-use project it completed in 2024. But now the company can expect energy and system maintenance costs to be far lower in the years ahead, say the energy specialists who worked with LCOR on the project.
“The first costs of a conventional system are always going to be cheaper, but the total lifecycle costs of a geothermal system are going to be far more financially feasible,” Arjun Mehta, vice president of Ecosave, said in an interview.
LCOR’s 1515 Surf Avenue on Coney Island in Brooklyn is the largest district geothermal project in New York City. According to Mehta, it shows how it’s possible to install a major geothermal system in a dense urban environment.
“In this case, there were buildings preexisting around it, so there is a very obvious logistical challenge on getting the drills into that very tight space,” said Mehta.
The 400,000-square-foot project includes retail and other commercial space and more than 460 residential units, about a quarter of which are for lower-income households. New York City classifies the geothermal system as a district project because the property is divided into two buildings.
To make the project feasible, LCOR relied on several public and private incentives, including $1.62 million in funding from New York’s community heat pump pilot program, $2.9 million from Con Edison’s utility clean heat program and a 30% federal tax credit.
“What makes the credit more palatable is that, once you have the high efficiency geothermal heat pumps that are connected to the same ground source loop, it qualifies a lot more equipment for the tax incentive,” Mehta said. “So it astronomically increases the incentive that you’re going to get from the federal government.”
Ecosave started work on the project months before construction began, first to conduct a feasibility study and then to drill the wells and install the piping and other system components.
The feasibility study gave the developer a picture of the system’s expected efficiency, based on the amount of bedrock and the soil content under the foundation.
“If there happens to be a lot of bedrock, you have good conductivity, so it allows a lot of heat flow,” said Patrick Towbin, COO and chief of engineering at Ecosave. “In areas where it has a lot of organics and mixed silts, things that don’t have good foundations, it tends to be a little more difficult, because it insulates better.”
For the project, Ecosave dug 153 bore wells to a depth of 500 feet in a pattern that matches the footprint of the two buildings. A rig can typically drill three wells a day, so for the Coney Island project it took about three months, Mehta said. Installing the piping and other components and constructing the mechanical room took another three months.
“In ideal circumstances, it should take 6-7 months to get a geothermal system put in place,” he said.
It’s easier to install geothermal on the front end of a new construction project, as was done here, than to retrofit an existing building, but it can be done, said Towbin.
“It’s better to have an open adjacent field [for a retrofit],” he said. “There is technology where you can do very low profile type work [on the existing site], but it takes a lot of casing and it’s more labor intensive and more expensive.”
Retrofits will get easier in the years ahead as the drilling technology improves, Towbin said. One recent innovation is angled drilling, he said.
“You can harness more of the space with angled drilling, more of the real estate beneath the surface,” he said.
New York state recently changed its rules to permit wells as deep as 800 feet. That will also increase the feasibility of projects — retrofit as well as new construction — Towbin said.
“The deeper you go, the better you can store energy and harvest it later,” he said.
Although conducting a feasibility study and drilling bore wells increases the time, complexity and cost of projects, geothermal can be cost-effective for properties as small as single-family houses, Towbin said. Once projects get past the installation phase, building operators can expect decades of predictable, clean and cost-effective heating and cooling with minimal maintenance, as long as the system is installed to the manufacturer’s specifications and is commissioned and operated correctly, the executives said.
“Once you’ve put up all the upfront costs, you have a closed cycle of cooling loop and rejection of heat that goes in one consistent network of pipes into the ground and that’s it right there,” said Towbin. “There’s really very little other than chemistry maintenance, and some pumping maintenance and things like that. Other than the units that are actually fit out at the location, there aren’t as many workable parts or pieces of equipment as a conventional system. That’s overall why it’s cheaper to maintain for a long period.”
