In situ thermal remediation has long been one of the most powerful tools available for addressing complex subsurface contamination, particularly dense non aqueous phase liquid source zones and recalcitrant chlorinated solvents. But traditional thermal conduction heating systems often come with significant tradeoffs—high energy demand, heavy electrical infrastructure, and limited flexibility in how heat is delivered and managed in the subsurface.
At The Environmental Remediation Group (ERG), we set out to challenge those constraints. The result is Hybrid Energy Thermal Remediation (HETR™)—a next-generation thermal conduction heating platform that delivers industry-leading subsurface temperatures while fundamentally rethinking how energy is supplied, managed, and reused during remediation.
We are proud to share that HETR™ is now protected under U.S. Patent No. 12,523,373, formally recognizing ERG’s approach to high-performance, lower-carbon thermal remediation.
What Makes HETR™ Different
At its core, HETR™ is designed to do two things simultaneously:
deliver more heat where it matters, and use energy more intelligently while doing it.
Unlike conventional TCH systems, HETR™ applies multiform energy through convective, conductive, and radiative heat transfer mechanisms, allowing precise thermal delivery both longitudinally within individual wells and laterally across a wellfield. This design enables stable and homogeneous subsurface temperatures that can exceed the sustainable output of traditional systems—while reducing unnecessary energy use.
From a performance standpoint, HETR™ is capable of:
- Targeting subsurface temperatures between 100°C and 400°C
- Delivering ~400–550 watts per linear foot of well
- Operating at well spacing as tight as 8 feet on center for high-temperature applications, or up to ~17 feet on center for moderate-temperature designs
These capabilities make HETR™ particularly well suited for aggressive source zone treatment, deep DNAPL remediation, and sites where thermal efficiency and control are critical.
Energy Smarter by Design
One of the defining features of HETR™ is its integrated energy harvesting capability.
Each HETR™ well is engineered to generate energy during operation using thermoelectric energy harvesting, producing approximately 100 to 500 watts per well, 24/7, depending on configuration and site conditions. This recovered energy can be reused to offset system demand, reduce reliance on grid power, and minimize the need for heavy electrical infrastructure.
In practical terms, this means HETR™ systems can be configured to operate in grid-connected, partially grid-connected, or fully off-grid modes (depending on application), and can be further integrated with auxiliary renewable sources such as solar where appropriate. The result is a thermal system that not only delivers higher performance, but does so with a materially lower lifecycle energy and carbon footprint than conventional approaches.
Field-Ready, Not Conceptual
While the patent issuance marks an important milestone, HETR™ is not a theoretical or pilot-scale concept.
ERG has one full-scale HETR™ project completed, two additional full-scale implementations currently underway, and more than 500 HETR™ wells planned for installation across projects scheduled in 2026. These deployments span real-world site conditions and remediation challenges, providing practical validation of system performance, reliability, and constructability.
This field experience has informed continuous refinement of the platform, including modular system configurations, adaptable energy inputs (combustive and or electric), and flexible well designs that allow targeted heat delivery at depth while optimizing efficiency across the treatment zone.
A New Standard for Thermal Remediation
HETR™ reflects ERG’s broader philosophy toward remediation technology: performance first, but never at the expense of efficiency, adaptability, or sustainability. By combining industry-leading thermal output with integrated energy recovery and flexible system architecture, HETR™ expands what is possible for high-temperature in situ remediation—particularly at complex, constrained, or energy-intensive sites.
With U.S. Patent No. 12,523,373 now issued, HETR™ stands as a protected, field-proven platform ready to support the next generation of challenging cleanup projects.
To learn more about HETR™ and ERG’s thermal remediation technologies contact Allen Swift, one of the co-inventors of HETR™:
Allen Swift, Chief Executive Officer
Mobile: (206) 271-1514
Email: aswift@1erg.com