In what is projected to be the hottest recorded summer in the United States, the U.S. power grid faces significant challenges in meeting the exponentially escalating demand for electricity. As temperatures increase, so does energy demand, often leading to spikes and increasing the risk of outages. One technology that has been around for decades in Europe that is gaining attention in the States is ground-source heat pumps. While originally seen as overly complex and expensive, new technologies and incentive programs are turning the tide.
What Are Ground Source Heat Pumps?
A geothermal heat pump, or “Ground Source Heat Pump” (GSHP), is an innovative and highly efficient technology that leverages the earth's relatively consistent underground temperature to provide heating, cooling, and hot water for buildings. Unlike an air-source heat pump (ASHP), which utilizes outside air, GSHPs transfer heat to or from the ground via a series of buried pipes known as closed loops. Depending on the available land and specific site conditions, these systems can be installed vertically or through inclined and directional drilling technologies.
GSHPs operate on the principle of heat exchange, which means that the baseload bedrock temperature is available all year, and relative to the ambient temperature, can serve as a heat sink, or a heat source. Storing this energy is also possible. A system can be designed to use the ambient heat in the summer, instead of dissipating heat into the atmosphere. The heat can be sent and exchanged into the bedrock. Then in the winter, the system can be designed to extract heat from a pre-charged resource providing higher efficiency to send it indoors to raise the interior air temperature. This process is highly efficient because the ground temperature remains relatively stable throughout the year, unlike the fluctuating temperatures of the outside ambient air.
Additionally, GSHPs are an environmentally friendly electrification solution that does not use any on-site fossil fuels. This significantly reduces greenhouse gas emissions compared to fossil fuel-based heating systems. The long-term benefits and potential for integration with renewable energy sources make GSHPs an attractive option for sustainable building projects.
GSHPs are making headway over ASHPs for a variety of reasons.
Efficiency: GSHPs are more efficient than ASHPs, particularly when ambient peak temperatures are at their most extreme. In those conditions, the Coefficient of Performance (COP) of an ASHP, which determines efficiency by electric conversion to heating (1 kW à X kW) will drop off dramatically. Unlike ASHPs, which must contend with those wide air temperature variances, GSHPs benefit from the earth’s stable thermal environment. This allows for a more predictable and reliable production rate resulting in higher operational efficiency, especially during peak heating and cooling seasons when the temperature delta or difference between the outside air and desired indoor air is the greatest.
Operating Cost: GSHPs have significantly lower operating costs because of this higher efficiency. The consistent ground temperature means GSHPs require less energy to achieve the desired indoor climate, resulting in substantial savings on heating and cooling costs over the system's lifespan.
Caption: Geothermal Heating & Cooling is 2-3x more efficient than Air Source Heat Pumps. Brightcore Energy, 2024
Suitability: In the past, GSHPs were considered more suitable for locations with ample space, whereas ASHPs could be installed in various environments due to their flexible system setup. However, recent advancements in geothermal technology have expanded the feasibility of GSHP installations. Innovative drilling techniques and compact system designs now allow GSHPs to be installed in dense urban areas and smaller properties (see Brightcore’s Groundbreaking technology operating in what was once the coal room of a landmark building in NYC here). Now that GSHPs have the capacity for both building retrofits and new builds, their advantage over ASHPs has grown wider. The other aspect of suitability is the installation environment itself. As ASHPs are exposed to the outdoors, their life expectancy can be compromised by those elements. A GSHP system has no such exposure and as such, weather does not play a role in its useful life.
Environmental Impact: GSHPs and ASHPs are more environmentally friendly than conventional heating and cooling systems, but GSHPs offer greater long-term environmental benefits. Due to their efficiency advantage, GSHPs consume less electricity to provide the same heating or cooling as ASHPs. This reduced energy consumption reduces greenhouse gas emissions when generation is sourced from fossil fuels. Additionally, their protected underground components result in fewer replacement parts, which means less environmental impact from the manufacturing and disposal of equipment. That increase in durability further minimizes maintenance-related emissions and resource use.
Renewable Energy Source: GSHPs utilize the earth’s natural heat, a renewable resource, to provide heating and cooling, contrasting with ASHPs which have no such renewable source.
Ground Source Heat Pumps and the U.S. Power Grid
Integrating GSHPs into the U.S. power grid is becoming increasingly popular due to severe weather patterns, which are driving the demand for more energy. This trend also highlights the growing reliance on infrastructure not designed initially to support our rapidly expanding energy needs. The Department of Energy concluded in 2021 that GSHPs could allow for as much as 24,500 miles (about 39428.93 km) of new grid transmission lines to be avoided by 2050.
(https://www.osti.gov/biblio/2224191). Instead of focusing on keeping up with energy demand and having to expand their supply infrastructure, utilities can focus on updating and improving their existing infrastructure.
Caption: (The existing power grid is over 160,000 miles long and supports over 17 trillion kWh per year, https://www.eia.gov/energyexplained/electricity/electricity-in-the-us-generation-capacity-and-sales.php)
Benefits of Utility-Specific Incentives
Utilities offering incentives may seem counterintuitive, yet they actively promote rebates, tax credits, and low-interest financing options. Ultimately, the goal of utilities incentivizing consumers to utilize GSHPs is to reduce peak demand on the grid, which helps maintain grid stability and reliability, particularly during extreme weather conditions when energy demand spikes. The integration of GSHPs also contributes to a more diversified energy infrastructure capable of withstanding various challenges and disruptions, putting less pressure on the grid to support a growing need for energy.
In addition to utility incentives, geothermal heating and cooling systems are often covered by federal incentives. The most important piece of legislature to support green funding in the US is The Inflation Reduction Act (IRA). This program provides tax credits and loans for property owners to adopt energy-efficient technology.
The IRA has also provided funding for state and local programs, allowing those entities
to develop additional grants and incentives. Programs like New York’s Climate Mobilization Act have publicized IRA incentives even more, as the mobilization act incorporated laws such as Local Law 97, which requires buildings to meet certain energy standards. This database lists all incentives for all renewables by state and can be filtered by geothermal.
The Future of Geothermal Heat Pumps
As the U.S. continues to seek sustainable solutions to its energy challenges, geothermal heat pumps are poised to play a critical role. Advances in technology are making these systems more accessible, efficient, and affordable, while increased awareness and incentives are driving adoption. Meanwhile, the need to transition is more prevalent than ever, as more and more mandates are being enacted. The transition to GSHPs represents a significant step towards US energy efficiency goals and ultimately supports a more resilient and environmentally friendly power grid.
To learn how you can prepare for the clean energy future and discover how GSHPs can reduce costs and help meet your sustainability targets, contact us today.
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