Hidden beneath the Earth’s surface is a rich source of geothermal energy that can help heat and cool homes. Currently, major cities in the United States are increasingly interested in this green energy source.
A “giant battery” lies just beneath our feet. However, unlike flammable lithium-ion batteries, this “battery” is completely stable, free, and can be sustainably harnessed. It is none other than the Earth.
Buildings can harness heat from beneath their foundations using geothermal energy for heating and cooling instead of relying on gas pipelines. The image shows snow covering New York City, USA, on January 16. (Photo: AFP/TTXVN)
While surface temperatures fluctuate throughout the year, underground temperatures remain stable. This area is rich in geothermal energy that engineers can tap into.
Cameron Best, the Business Development Director at Brightcore Energy (USA), stated: “Every building sits on a thermal asset. This is an efficient way to heat and cool our homes.” In summer, heat pumps cool spaces by transferring indoor heat into water, which is then pumped back into the Earth. This process warms the ground, recharging the “underground battery” with enough energy to extract in winter.
Months ago, Eversource Energy (USA) launched the first geothermal-connected residential community in Framingham, Massachusetts.
Pipes run down boreholes about 180-215 meters deep, where the rock temperature is consistently 13 degrees Celsius. A mixture of water and propylene glycol is pumped through the pipes, absorbing geothermal energy, then flowing to 31 residential homes and five commercial buildings.
Heat pumps use this fluid to heat or cool spaces. If deployed nationwide, these geothermal systems could significantly contribute to carbon reduction in buildings, which account for about one-third of total greenhouse gas emissions in the U.S. In 2023, New York became the first state to ban natural gas in most new buildings.
Once operational, buildings can draw heat from the water pumped from below their foundations, instead of burning natural gas transported from afar. The geothermal energy network does not require special geology to function, which means they can be installed almost anywhere. Companies also use the same equipment for gas pipelines to apply it to geothermal energy extraction.
Although geothermal energy is quite efficient, it remains unclear how it will impact customers’ electricity bills. As companies are still testing this system, they have not agreed on a pricing framework.
