What Is a Geothermal Renewable Energy Credit (GREC)?
A Geothermal Renewable Energy Credit (GREC) is a tradeable, market-based certificate issued for every megawatt-hour (MWh) of thermal energy produced by a qualified geothermal heat pump system. These credits represent the legal proof of renewable energy generation and serve as the primary currency for state-mandated environmental compliance. State utility companies are required by law to buy a specific percentage of their energy from renewable sources, and GRECs are the mechanism they use to meet the geothermal portion of those green energy obligations.
The Science and Measurement of Thermal Credits
GRECs are created when a certified geothermal heat pump system produces thermal energy—effectively heating or cooling a building by utilizing the earth's constant underground temperature rather than burning fossil fuels or relying on inefficient air-source heat pumps. Each MWh of thermal output is recorded in a highly secure tracking registry, such as PJM-GATS for Maryland and Virginia, or NEPOOL-GIS for New Hampshire, and assigned a unique serial number. These certificates can then be sold on the open market to utilities that must purchase them to avoid hefty fines. Because geothermal systems work 24/7 regardless of weather conditions, they produce a steadier stream of credits throughout the year compared to intermittent sources like wind or solar. You can learn more about the technical measurement of these credits in our /glossary section, which defines the conversion from BTUs to MWh.
Comparing GRECs to SRECs and Other Credits
While both GRECs and SRECs (Solar Renewable Energy Credits) are tradeable renewable energy certificates, they emerge from fundamentally different technologies and trade in entirely separate markets. SRECs are generated by solar photovoltaic panels and are measured in MWh of electricity generated. In contrast, GRECs are generated by geothermal heat pumps and are measured in MWh of thermal energy. This is a crucial distinction because thermal energy is often more efficient to produce and has different legislative 'carve-outs.' Because geothermal programs are newer and have dedicated mandates in fewer states, the GREC supply is often much tighter relative to utility demand. This scarcity can support premium pricing that exceeds the value of more common renewable credits. For installers looking to explain this to clients, our /for-installers page provides helpful breakdown materials.
The Current Landscape of GREC Markets
As of 2025, active and lucrative GREC programs exist specifically in Maryland, Virginia, and New Hampshire. Other states are moving quickly to catch up; for example, Pennsylvania is advancing legislation known as the PRESS Act to elevate geothermal energy to Tier I status, which would create a robust new GREC market. Each state maintains its own unique eligibility requirements, pricing ceilings, and preferred tracking registry. Maryland currently uses PJM-GATS and features the most established market with a trading price near $87/MWh. Virginia also uses PJM-GATS but operates under a different Alternative Compliance Payment (ACP) structure. New Hampshire utilizes the NEPOOL-GIS system for its thermal credits, which currently average around $27/MWh. You can find a full breakdown of these state-specific nuances on our /states page to see which rules apply to your property.
Determining the Value of Your System
The market value of your GRECs is influenced heavily by the state's Alternative Compliance Payment (ACP) ceiling—the specific penalty fee that utilities must pay to the state if they fail to purchase enough credits. In Maryland, for example, several legislative sessions have solidified a high ACP for geothermal, leading to GREC trades at $87 per MWh in 2025. The actual revenue your system earns will depend on factors like system size (measured in tons), the Coefficient of Performance (COP), and local climate conditions. A larger, more efficient system will naturally generate more MWh of thermal energy and, consequently, more GRECs. To get a high-accuracy estimate of what your specific installation might generate annually, we recommend using our online /calculator, which factors in these technical variables across different state markets.
The Path to Monetization: Registration and Sales
To start earning GRECs, your geothermal system must be registered with your state's certification authority and then enrolled in a professional tracking registry. This process involves submitting engineering documents, AHRI certificates, and photos of the installation to prove the system meets state efficiency standards. Emergent Energy specializes in handling this entire complex process—from the initial documentation collection to state certification and finally registry enrollment—at no upfront cost to the homeowner. Once your system is registered, we manage the quarterly reporting and find buyers for your credits at the highest current market prices. Visit our /how-it-works page for the full five-step process that takes a system from installation to payday, or check our /faq for answers to common questions regarding credit ownership and payment timelines.
Long-Term Financial and Environmental Benefits
Owning a geothermal system that produces GRECs is like having a private annuity that pays you for helping the environment. Beyond the immediate energy bill savings, the GREC payments provide a recurring cash flow that can pay back the entire 'premium' cost of a geothermal system over several years. This makes geothermal one of the few home improvements that actually pays for itself. Furthermore, as states increase their renewable energy goals (often aiming for 50% or 100% renewables by 2040 or 2050), the demand for high-quality, reliable thermal credits like GRECs is expected to remain strong. This long-term legislative stability provides peace of mind for homeowners making a 20-year investment in their home's infrastructure. To see if your system is a good candidate for this revenue, you can /evaluate your property today using our simple online tool.
Why Utilities Prefer Geothermal Credits
From a utility perspective, GRECs are an attractive way to meet environmental mandates because geothermal energy is a 'baseload' renewable. Unlike solar, which stops producing at night, or wind, which varies with weather patterns, geothermal heat pumps operate whenever a building needs climate control, displacing heavy electrical or fossil fuel loads during peak grid stress. Utilities are often willing to pay a premium for credits that represent this reliable displacement. By participating in a GREC market, you are helping your local utility stabilize the grid while reducing the overall carbon footprint of your community. This symbiotic relationship between homeowners and utilities is facilitated by aggregators like Emergent Energy, who ensure the market remains liquid and fair. Read more about the history of these programs on our /glossary page.