There’s a battery underneath your feet, and utilities want to use it
There’s a battery underneath your feet, and utilities want to use it
As the country tries to decarbonize, more things are going electric — not just cars and buses, but heating systems too. New York expects its electricity demand to double by 2050 and Massachusetts expects peak seasonal demand to move from summer to winter, on account of electric heating, by 2036 and more than double by 2050.
Accommodating this will cost billions of dollars. National Grid, a utility in Massachusetts, said it will have to increase spending eightfold to meet the coming demand.
That demand, and legislation, (PDF) have lit a fire under utilities, which are looking for ways to carry the burden.
One way is being tested in a small neighborhood in Framingham, Massachusetts. At the end of a parking lot is what looks like a 30-foot-tall mechanical scorpion’s tail.
“What we’re looking at now is actually a drill rig,” explained Nikki Bruno, vice president of clean technologies at utility Eversource. “But it’s a little bit different than, say, what you would notice if you had a water well drill, which is straight up and down. This is actually deviated drilling.”
The rig can drill at an angle, and it’s creating a network of boreholes 700 feet deep that will connect to pipes looping under the neighborhood. The pipes will be full of water carrying thermal energy for heating and cooling buildings.
“We’re trying to test the success of a networked geothermal system,” Bruno said.
It’s a geothermal system, but there’s no lava or volcano in Massachusetts. Just the constant 55-or-so-degree temperature underground, which is fairly stable no matter the season. For this array, the ground — the regular, old ground — is like a battery. It can supply and even store energy.
“You can do this in all 50 states. It’s basically utilizing the constant temperature of the earth as a heat source in the winter and a heat sink in the summer,” said Ryan Dougherty, president of the Geothermal Exchange Organization, a trade group.
The water flowing through the loops of pipes deep beneath this area of Framingham does not heat or cool buildings directly the way steam through a radiator might keep you warm in winter or a breeze might cool you in summer.
Instead, it contributes energy to a device in every building called a ground source heat pump that is itself powered by electricity. Like air conditioners or gas heaters, which work at significantly inferior efficiency, the heat pump is doing the heating and cooling. It is assisted greatly by the ability to draw energy from — or deposit waste heat into — the geothermal pipes.
“It is very much like the refrigerator in your kitchen, but it can work both ways,” Dougherty said.
Construction is almost finished at the geothermal pilot project in Framingham at a cost of $14 million, paid by the utility. Participants don’t pay for the installation, and their heating and cooling bills are expected to fall.
What makes the two-year project the first of its kind run by a utility is that this system will span a whole neighborhood — a low-income housing project, a gas station, a cabinet store, a fire station, all connected in a network.
“When you connect a bunch of different buildings that all have different thermal needs, you can basically move the energy around in a circuit to where it’s needed or away from where it’s not needed,” Dougherty explained.
In theory, one building’s exhaust heat can help warm up another building.
“That ice rink and the greenhouse down the street — they are canceling each other’s loads,” said Audrey Schulman, a co-founder of HEET, a nonprofit incubator for climate solutions. Schulman said heat pumps connected to geothermal loops are twice as efficient as traditional heat pumps that pull heat out of the air and five times more efficient than gas power.
“Ground source heat pumps in general are one of the most efficient methods of heating and cooling, and then networking them together you get additional efficiencies,” she said.
That efficiency is why 26 utilities representing 50% of all gas customers in the country are actively exploring this technology, according to HEET. Utilities are staring down the barrel of exploding demand for electricity as decarbonization progresses.
“You’re gonna need to electrify a ton of buildings,” said Alexander Buell, director of portfolio planning and analysis at energy company Con Edison. Even if those buildings are converted from fossil fuel heating to traditional heat pumps, “it’s going to require a massive buildout of the entire electrical system.”
Geothermal networks could reduce that burden significantly. They are not cheap to install — Schulman said the upfront cost is 60% higher than a similar gas system. “But because you’re getting rid of the whole fuel costs, you’re substituting it with a very, very efficient amount of electricity, in the end the customer’s energy bills will be lower,” she said. “And the customer’s always the one who pays for the system in the end.”
The fact that geothermal networks still involve pipes and drilling, just like oil and gas, has earned it the support of labor unions concerned about job losses in the transition away from fossil fuels.
The pilots emerging in 13 states are designed to test the economic viability and effectiveness of geothermal networks in practice. Buell, at Con Edison, is hopeful. “We as a society will need to do a massive reimagining of our energy systems over the next few decades to be able to reduce our carbon emissions,” he said.
Part of that may be the free battery underneath our feet.
Stories You Might Like
There’s a lot happening in the world. Through it all, Marketplace is here for you.
You rely on Marketplace to break down the world’s events and tell you how it affects you in a fact-based, approachable way. We rely on your financial support to keep making that possible.
Your donation today powers the independent journalism that you rely on. For just $5/month, you can help sustain Marketplace so we can keep reporting on the things that matter to you.
