Our Stories: A Key to the Clean Energy Future Could Lie Under Our Feet
Right below the street, the earth’s temperature rises and falls with the seasons. But just 10 to 15 feet down, the earth remains a steady 55 degrees. And it could be an abundant source of energy that helps unlock the clean energy future. Why? Geothermal energy.
WHAT IS GEOTHERMAL ENERGY?
Geothermal energy in the ground acts like a battery of stored energy and can be used to heat and cool buildings with heat pumps, rather than fossil fuels. This allows for more sustainable heating and cooling.
Since 2020, we’ve been promoting geothermal heat pumps to homeowners. Now, we’re working on scaling the technology so multiple buildings across a neighborhood can use it with what is known as a thermal energy network.
“This is extremely exciting because for the first time in over 100 years, we're developing a whole new commodity for the company, and really for the state and even the whole country,” says Greg Koumoullos of Customer Energy Solutions, the department manager leading the company’s thermal energy networks initiative.
HOW DO THERMAL ENERGY NETWORKS WORK?
Thermal energy networks connect multiple buildings through a loop of underground pipes carrying a water-based fluid. The fluid maintains a constant temperature of about 50 to 70 degrees by exchanging heat with the earth through geothermal boreholes, and/or by capturing excess heat from sources like data centers in buildings on the network.
Each building connects to the thermal energy network using a ground source heat pump that transfers heat from the underground loop into buildings during the winter and removes heat come summer.
Koumoullos said we started looking at thermal energy networks in 2019 when we were studying retiring leak-prone pipes on our natural gas system. These networks are already common in places like Vancouver, Canada and Stockholm, Sweden.
The technology gained support here in summer 2022 when New York state passed the Utility Thermal Energy Network and Jobs Act. It requires the seven largest utility companies in the state to pilot thermal energy networks. Other states including, Massachusetts, Colorado, and Minnesota, Washington, Maryland, Vermont, and California have also passed legislation allowing or mandating utilities to create thermal energy network pilots.
PILOT PROJECTS LEADING THE WAY
We proposed three projects, each varying in design, to our regulator, the Public Service Commission. And we’re requesting $255 million to complete these initiatives.
Chelsea: In this section of Manhattan, a thermal energy network would repurpose excess heat from a data center to cool, heat, and/or provide hot water to more than 300 apartments in nearby New York City Housing Authority buildings.
Mount Vernon: In this Westchester city, single-family homes, affordable multifamily buildings, churches, a fire station, medical offices, and the community recreation center would draw heat from geothermal boreholes.
Rockefeller Center: A thermal energy network would capture waste heat from a “central plant” at Rockefeller Center and use it to heat three surrounding buildings on the campus owned by different entities.
Both the Chelsea and Mount Vernon projects are in state-designated disadvantaged communities, meeting New York’s law requiring every company to propose at least one pilot in a neighborhood disproportionately affected by environmental harms.
“Having a variety of projects testing different technologies is going to give us an opportunity to really see what works for our service territory,” says Kristina Le-Gallo, a clean energy project lead on the customer outreach side of the new Thermal Energy Networks section of Clean Energy Solutions.
THE ENVIRONMENTAL AND ECONOMIC BENEFITS
Buildings are the largest source of greenhouse gas emissions in New York state. Scaling these projects can help improve air quality, and that’s exciting, she says.
“We’re not going to reach our state’s decarbonization goals with just one solution. Thermal energy networks are an entirely new decarbonization tool to add to our toolkit,” Le-Gallo says.
Plus, thermal energy networks are extremely efficient. Each of our pilots is expected to reduce strain on the electric grid; the technology would use 45 to 70% less energy than would be needed for electrifying the same buildings with air-source heat pumps.
As we design, reliability remains a driving force. That’s why we’re incorporating backup sources of energy into each loop.
“We want to make sure our customers, no matter who they are, are getting the energy they expect, whether it’s the coldest day in the winter or the hottest day in the summer,” says Dzenana Lukovic, who along with Brittni Provencher, works on the technical aspects of the networks as part of our Thermal Energy Networks group.
WORKFORCE OPPORTUNITIES
Another benefit is that thermal energy networks use similar piping infrastructure to the current gas system, which our workforce is skilled at constructing and repairing.
The key is learning from these pilots and seeing how they can help customers and our company. For the pilots, we plan to cover most—and in some cases all—of the customer costs, which include replacing boilers and furnaces with heat pumps as well as grid connection and construction. During our work, we'll add energy efficiency measures to customer homes.
Meanwhile, Melanie Mangone, another clean energy project lead for UTEN pilots, is heading up the customer protections and rate-design efforts in collaboration with Rate Engineering for all three test projects.
“We anticipate customers’ total bills will decrease due to the system’s higher efficiency, but since this is a first-of-its-kind project in New York and involves communities with vulnerable residents, we will implement a bill cap for added protection.” she says.
“Our goal is to gather data and information to determine if it makes sense for utilities to own and operate thermal energy networks, while protecting all our customers.”
Being part of a thermal network could be less costly for individuals, such as homeowners interested in installing their own geothermal systems.
For entities like Tishman Speyer, the real estate company that owns some of the buildings on the Rockefeller Center campus, there’s the added value of helping meet city and state climate goals by lowering carbon emissions.
“I think the fact that the utility is taking this on is huge. It comes with our brand,” says Koumoullos.“You can trust in our company. That’s key.”