Growing heat waves make geothermal energy vital to reducing grid demand

Heat waves are more common, longer lasting and more extreme. That puts added pressure on the electricity grid in America and requires us to think about underutilized sources of renewable energy. The leading candidate for prioritization is geothermal ground source energy, which, like solar energy, can be used by homeowners, commercial property owners and institutions. It can save money over time for all three, while benefiting the planet and easing the grid’s burden.

The need is urgent. Western states have been sizzling under extended triple-digit temperatures. At least 10 places in California reached all-time high temperatures in September; Sacramento hit 116 degrees. The California grid had record demand of 52,061 megawatts (MW) on Sept. 6; the previous record was 50,270 MW in 2006.

National demand will only grow, as America begins to shift to electric vehicles to reduce carbon emissions. Solar and wind energy can address part of the demand, but both have challenges with consistency and transportation of energy. That’s why geothermal ground source energy is crucial.

Geothermal ground source energy is thermal energy extracted or stored in the ground subsurface. That energy can be accessed from lot areas to provide efficient heating and cooling for nearby buildings. Its great benefit is that the stored thermal energy is reusable. Electric energy is needed to access it, but at a reduced level that helps make the grid more sustainable. 

For individual properties, a geothermal ground source heat pump system works as follows: A series of pipes buried in vertical wells, or in some locations submerged horizontally below ground, allow fluid to circulate to the building’s heat pump system. This system provides heated or cooled air, water, or refrigerant for the building. In winter the heat pump extracts heat from the ground. In summer the reverse occurs: It moves heat from the building into the ground.

Property owners typically would need outdoor space (a yard in the case of a home; a parking area for a commercial property). Generally speaking, geothermal ground source energy systems are best suited to larger lots where the energy use per acre is not as great. Even with smaller lots, a hybrid solution can be efficient. Campuses of colleges, medical centers, municipal government complexes and housing or office developments are especially well-suited. Multiple buildings can be served by a geothermal loop connecting them all. 

While the geothermal ground source energy is free, there is a cost to extract and circulate it, and there are upfront expenses associated with installing the geothermal system. The cost can be justified best when a new heating or cooling system is needed, with much of the cost recovered over time in savings and reductions in carbon emissions. In addition, incentives are available from the federal government and often from state and local energy providers. 

Because a geothermal system is typically delivered to nearby buildings, it does not require massive infrastructure to transport it from a distance or to store it. Geothermal heat pump systems do need electricity to move the fluid around, but that requires a relatively small amount of electricity, reducing the burden on the electrical grid. In the case of a college campus, that electricity could be generated by nearby solar or wind power. 

Colleges and universities are leading the way on geothermal ground source energy in America. Princeton University’s geothermal system will replace steam generation in more than 180 buildings. Carleton College in Minnesota is “installing more than 60 miles of piping,” among other geothermal-related improvements, according to the Energy News Network. “After the system’s completion, energy use is projected to plummet 40 percent.”

Two free online tools — which we were involved in creating — are especially timely and deserve broader consideration by property owners, in light of growing electricity demand. In 2018, we helped pioneer for the City of New York the first Geothermal Ground Source Screening Tool. It lets property owners easily assess the cost-effectiveness of geothermal heating and cooling for every lot in the city — nearly 900,000 lots. It provides a rapid understanding of any property’s potential, given the site’s mixture of lot size, topography and building type. In 2021, Westchester County, New York City’s neighbor to the north, replicated the city’s tool, creating “Westchester GeoPossibilities,” which enables assessment of all properties in the county.

Both tools are models that can be replicated across the country: New York’s version by urban areas, and the Westchester version by suburban and more rural jurisdictions. In that context, it’s important to note that the Westchester tool was created with support from the New York State Energy Research and Development Authority (NYSERDA). Other states may want to consider providing such support as well. Property owners don’t need to wait, however, for those replications. Local engineers can assess the potential of individual properties on their own.

There has never been a more important time for the application of geothermal ground source energy. It’s time for all property owners to explore its potential.

Charles Copeland is president and CEO of New York City-based Goldman Copeland Consulting Engineers, where Tristan Schwartzman is a principal and the director of Energy Services. Copeland was named Energy Engineer of the Year (2006) by the Association of Energy Engineers (AEE). Schwartzman was named Energy Engineer of the Year (2022) by the New York Chapter of the AEE.