Green Therma
Green Therma ApS (Denmark, founded 2023) developed the Heat4Ever™ closed-loop geothermal system and patented DualVac™ vacuum-insulated pipe technology to extract renewable heat from 3-4 km depth for district heating utilities and industrial consumers, with first commercial delivery scheduled for 2027.
- Company typePrivate
- Founded2023
- HeadquartersCopenhagen, Denmark
- Headcount11–50
- GTM typeB2B
- OfferingServices
What Green Therma does
Green Therma ApS is a Danish clean energy company founded in 2023 that has developed the Heat4Ever™ closed-loop deep geothermal heat extraction system based on its patented DualVac™ vacuum-insulated pipe-in-pipe technology. The system circulates water through a single sealed deep horizontal well at 3-4 km depth, absorbing heat from surrounding rock at 90-150°C and delivering it to the surface with minimal heat loss via continuous vacuum insulation. Each well produces 2-4 MW of thermal energy — enough to heat approximately 1,500 households — with a designed operational lifespan of 50+ years and minimal maintenance, since the oxygen-free closed-loop architecture prevents corrosion and avoids contact with groundwater.
The company serves district heating utilities and industrial heat consumers (80-120°C applications including greenhouses, breweries, hospitals, universities, and industrial parks) seeking baseload renewable heat that is independent of weather, seasonal variation, and specific geological reservoir conditions. Its primary commercial anchor is the Aalborg Forsyning demonstration project — a 100+ MDKK investment structured under a 30-year heat supply agreement that is expected to deliver approximately 2 MW to roughly 1,000 households from 2027. Additional pipeline activity includes signed Letters of Intent with Stadtwerke Wismar GmbH (Germany, May 2026) and Geothermie Rupertiwinkel GmbH (Bavaria, March 2026), and a technical demonstration with GFZ Helmholtz-Zentrum für Geoforschung at Gross Schönebeck (Germany) to validate DualVac performance at depths exceeding 3 km.
Commercialization is executed through enterprise direct sales to utilities, supported by a strategic business network of six major oilfield services and energy equipment partners — SLB, Baker Hughes, Halliburton, KCA Deutag (now part of Helmerich & Payne), Nabors, and Tenaris — which collectively provide global drilling rigs, well construction, directional drilling expertise, digital drilling technology, and tubular manufacturing for Heat4Ever deployments. Revenue streams include long-term heat supply agreements, technology licensing and project development, and recurring monitoring and optimization services over multi-decade asset lives. The company is privately held, headquartered in Copenhagen, with subsidiary Green Therma GmbH in Hamburg and additional offices in Stavanger (Norway) and Frisco, Texas (USA). Revenue is not publicly disclosed and the company is pre-revenue with first commercial heat delivery scheduled for 2027.
Green Therma firmographics
Firmographics- Name
- Green Therma
- Legal name
- Green Therma ApS
- Website
- https://greentherma.com
- Company type
- Private
- Founded year
- 2023
- Operating status
- Operating
- Headcount range
- 11–50 employees
- Short description
- Green Therma ApS (Denmark, founded 2023) developed the Heat4Ever™ closed-loop geothermal system and patented DualVac™ vacuum-insulated pipe technology to extract renewable heat from 3-4 km depth for district heating utilities and industrial consumers, with first commercial delivery scheduled for 2027.
- Ownership category
- akta.pro rank
Green Therma industry classification
Industry- Product category
- Geothermal Heat Services
- NAICS
- Geothermal Electric Power Generation (221116), Power Boiler and Heat Exchanger Manufacturing (33241), Heating Equipment (except Warm Air Furnaces) Manufacturing (333414), Steam and Air-Conditioning Supply (221330)
- SIC
- Oil & Gas Field Services, Nec (1389), Cogeneration Services & Small Power Producers (4991), Heating Equipment, Except Electric & Warm Air Furnaces (3433)
- akta.pro primary industry
- Closed-Loop Geothermal Power Generation (Advanced Geothermal Systems) (EUACAHAE)
- akta.pro secondary industries
- Geothermal Equipment & Component Manufacturing (Turbines, Heat Exchangers, Pumps, ORC Units) (EUAMAEAI), Geothermal Power Plant Development & IPP (Permitting, Financing, Project Development) (EUAMAEAD), Geothermal Drilling & Well Construction (Production/Injection, Directional, Well Services) (EUAMAEAB), Geothermal Grid Integration & Power Offtake (Interconnection, PPAs, Ancillary Services) (EUAMAEAK)
Keywords
Where Green Therma is headquartered
LocationHeadquarters
- HQ city
- Copenhagen
- HQ country
- Denmark
- HQ region
- Europe
Offices4 records
Markets served
Green Therma business model
Business model- GTM type
- B2B
- Offering type
- Services
- Cost components
- Technology or R&D, Infrastructure, Operations, Personnel, Marketing or Sales
Revenue model
- Heat Supply Agreements: Long-term heat supply contracts (e.g., 30-year agreement with Aalborg Forsyning) providing stable, predictable cash flows from renewable heat delivery to district heating networks
- Technology Licensing and Project Development: Providing Heat4Ever technology, DualVac systems, and integrated project delivery to utility companies, industrial customers, and project developers globally through strategic partnerships
- Geothermal Monitoring and Optimization Services: Ongoing monitoring and optimization services helping operators maximize yield and ensure efficient, stable operation over decades
Go-to-market motion1 record
Distribution channels6 records
Marketing channels5 records
Green Therma product offering
Product offeringCore offering
Green Therma develops and deploys the Heat4Ever™ closed-loop geothermal solution, which uses a patented single deep horizontal well and DualVac™ vacuum-insulated pipe technology to extract renewable heat from 3-4 km depth at 90-150°C without requiring permeable geological reservoirs. The company delivers full-scale geothermal projects to district heating utilities and industrial heat consumers through strategic oilfield services partnerships, and provides ongoing monitoring and optimization services plus long-term heat supply agreements (such as the 30-year contract with Aalborg Forsyning).
Product overview
Green Therma offers a unified product portfolio centered on the Heat4Ever™ closed-loop geothermal solution, which combines the proprietary DualVac™ vacuum pipe technology with topside facilities and digital systems. The Heat4Ever solution uses a single deep horizontal well (approximately 4 km vertical, 2-3 km horizontal sections) to extract geothermal heat from 90-150°C rock formations without geological reservoir dependencies. The DualVac technology provides continuous vacuum insulation to minimize heat loss during transport. Green Therma also provides ongoing monitoring and optimization services to ensure efficient long-term operation. The solution is designed for district heating networks and industrial applications requiring 80-120°C temperatures, producing 2-4 MW per well (equivalent to approximately 1,500 households).
Differentiator
Problem solved
Functional benefit
Products and services
- Heat4Ever™ Closed-Loop Geothermal Solution Patented closed-loop geothermal solution that uses a single deep horizontal well (~4 km vertical and 2-3 km horizontal sections) to extract renewable heat from 90-150°C rock formations at 3-4 km depth. The system circulates water in a completely closed pipe without contacting the subsurface, delivering 2-4 MW per well — enough to heat approximately 1,500 households — for district heating networks and industrial consumers.
- DualVac™ Vacuum Pipe-in-Pipe Technology Patented single-well dual pipe technology providing continuous vacuum insulation along the entire pipe system, separating cold and hot fluid like a thermos flask to minimize heat loss and maximize energy production during transport from >3 km depth. Integral to Heat4Ever and available for technology licensing and integration into customer projects.
- Geothermal Monitoring and Optimization Services Ongoing data-driven monitoring and optimization services that help operators maximize geothermal yield and ensure efficient, stable operation over decades. Combines digital systems with operational expertise across the asset lifecycle.
Quantifiable outcome
- 2-4 MW heat output per single well, enough for approximately 1,500 households
- +3 more outcomes
Companies that use Green Therma
Customer profileNamed customers3 records
Segments3 records
Ideal customer profiles3 records
Green Therma technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature3 records
Green Therma partnerships and signals
Strategic signalPartnerships
13 partnerships are on record, tiered minor and core.
- Stadtwerke Wismar GmbHminorLetter of Intent signed May 2026 to jointly assess potential for deploying geothermal heating solution in Wismar, Germany. Project will begin with pre-feasibility study including geological screening and technical evaluation before considering full feasibility study.
- TenariscoreStrategic partnership announced May 2026 combining Green Therma's Heat4Ever solution with Tenaris's global expertise in tubular manufacturing, TenarisHydril premium connections, and well services. Collaboration aims to advance next-generation closed-loop geothermal systems across Europe with a full European supply chain to reduce reliance on imported energy and strengthen Europe's energy independence.
- Geothermie Rupertiwinkel GmbHminorLetter of Intent signed March 2026 to explore feasibility of deploying Heat4Ever closed-loop technology in Rupertiwinkel geothermal area, Bavaria, Germany. Initial phase focuses on feasibility assessment including geological analysis and heat demand evaluation.
- Aalborg ForsyningcoreFirst Heat4Ever demonstration project partnership. Aalborg Forsyning provides site at Industrivej 12G in Storvorde and purchases heat through 30-year agreement. Green Therma invests, establishes, and operates the ~2 MW plant. Project cost 100+ MDKK with completion expected 2027.
- KCA Deutag (now Helmerich & Payne)coreStrategic collaboration with KCA Deutag and SLB to deliver Heat4Ever wells to public and private clients. KCA Deutag delivers drilling rig and associated services, supported by Kenera business unit for rig technologies and digital services. First project is full-scale demonstration with horizontal well at ~3.5 km depth.
- SLBcoreStrategic alliance to develop and provide Heat4Ever closed-loop geothermal well solution worldwide. SLB provides well design, drilling expertise, digital drilling solutions, well construction services and monitoring equipment for pilot and commercial wells. First milestone was drilling a complete pilot well in Denmark in 2024.
- NaborscoreCollaboration for drilling deep horizontal wells enabling geothermal production with Heat4Ever. Nabors provides advisory planning, drilling expertise and operational experience. Valuable experience from extensive horizontal well drilling in USA and Middle East ensures safe and efficient completion of future Heat4Ever wells.
- Baker HughescoreStrategic collaboration agreement for access to Heat4Ever solution with DualVac technology and joint development of relevant geothermal projects globally. Leverages Baker Hughes expertise in energy technology development.
- HalliburtoncoreAgreement for Heat4Ever solution access with DualVac technology and collaboration on geothermal project development globally. Halliburton's 70 years of geothermal experience helps reduce risks, increase efficiency, and maximize asset value throughout the geothermal well lifecycle.
- GFZ Helmholtz-Zentrum für GeoforschungcoreCollaboration on DualVac technology demonstration project at Gross Schönebeck research facility in Germany. GFZ provides geothermal expertise and advanced test facilities. Project tests vacuum insulation at >3 km depth and validates system performance under various operating conditions over one year.
- Aarhus UniversityminorProject partner conducting geological studies supporting development, implementation, and commercialization of new geothermal solution for Aalborg demonstration project.
- GEUS (Geological Survey of Denmark and Greenland)minorProject partner conducting seismic surveys and developing geological models providing crucial knowledge for drilling operations at Aalborg demonstration site.
- Energy Cluster DenmarkminorProject partner managing funding compliance, reporting, networking, and dissemination for Aalborg demonstration project.
Scale indicators7 records
Recent moves6 records
Expansion highlights9 records
Green Therma competitors and assessment
Company assessmentEmerging players
- Fervo Energy: US-based enhanced geothermal systems (EGS) company using horizontal drilling and fracking techniques adapted from oil & gas. Targets both geothermal power and direct-use heat; comparable in addressing scalable deep geothermal but uses a different (reservoir-based) technical approach.
- Sage Geosystems: US-based deep geothermal developer focused on closed-loop and near-closed-loop systems for baseload power and heat. Directly comparable in targeting dispatchable geothermal heat/power independent of geological conditions.
- Vulcan Energy Resources: Germany/Australia-based developer of deep geothermal heat and lithium extraction projects in the Upper Rhine Valley, supplying low-carbon heat to industrial customers. Comparable as a European deep geothermal heat provider targeting decarbonization of industrial and district heating demand.
- AltaRock Energy: US-based enhanced geothermal systems developer pursuing commercial-scale EGS for baseload renewable power. Comparable in targeting scalable deep geothermal independent of natural hydrothermal resources, though US-focused.
Broad incumbents
- Enefit: Estonian state-owned energy company developing oil shale-to-heat and deep geothermal projects for district heating in the Baltics. Comparable in district heating decarbonization focus and Northern European operating geography.
- Ormat Technologies: Established global leader in conventional geothermal power generation with manufacturing of binary and flash power plants. Comparable as a public-market reference for geothermal project economics and scale, but operates in conventional hydrothermal rather than closed-loop systems.
Direct peers
- Eavor Technologies: Canadian closed-loop geothermal developer using a multilateral well design (Eavor-Loop) to extract heat from deep rock without requiring hydraulic fracturing or permeable reservoirs. Most directly comparable to Green Therma's Heat4Ever in technology approach and target market of district heating.
- Baseload Capital: Swedish investment firm dedicated to financing and developing deep geothermal projects globally, with portfolio companies using both EGS and closed-loop designs. Comparable as a capital and project development partner active in the same European district heating segment.
Regional players
- Reykjavik Geothermal: Iceland-based developer of high-temperature geothermal power and direct-use heat projects in East Africa, Asia, and Central America. Comparable as a project developer in deep geothermal, though primarily focused on conventional high-resource areas.
Others
- Seequent (Bentley Subsurface): Subsurface software and modeling provider widely used in geothermal and oil & gas projects. Comparable as an enabling technology supplier supporting geothermal reservoir engineering, drilling, and wellfield design — adjacent ecosystem player.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks7 records
Key highlights7 records
Customer concentration
Green Therma social profiles
Digital presenceGreen Therma financial estimates
Financial estimateRevenue estimate
Valuation estimate
Green Therma leadership team
Management profileNumber of profiles
Profiles8 records
Green Therma subsidiaries and ownership
Company hierarchySubsidiaries1 record
Green Therma funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Green Therma M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Green Therma
What does Green Therma do?
Green Therma develops and deploys the Heat4Ever™ closed-loop geothermal solution, which uses a patented single deep horizontal well and DualVac™ vacuum-insulated pipe technology to extract renewable heat from 3-4 km depth at 90-150°C without requiring permeable geological reservoirs. The company delivers full-scale geothermal projects to district heating utilities and industrial heat consumers through strategic oilfield services partnerships, and provides ongoing monitoring and optimization services plus long-term heat supply agreements (such as the 30-year contract with Aalborg Forsyning).
Is Green Therma a public or private company?
Green Therma is a private company. It is classified as venture growth investor backed and is currently operating.
When was Green Therma founded?
Green Therma was founded in 2023. It employs 11 to 50 people.
Where is Green Therma based?
Green Therma is headquartered in Copenhagen, Denmark, in the Europe region.
How does Green Therma make money?
Three revenue lines are on record. Heat Supply Agreements are the primary driver. The others are technology Licensing and Project Development and geothermal Monitoring and Optimization Services.
Who are Green Therma's main competitors?
Emerging players on record are Fervo Energy, Sage Geosystems, Vulcan Energy Resources and AltaRock Energy. Broad incumbents are Enefit and Ormat Technologies. Direct peers are Eavor Technologies and Baseload Capital. Reykjavik Geothermal is listed as a regional player. Seequent (Bentley Subsurface) is listed as an others.
Does Green Therma have an API?
No public API is recorded for Green Therma.
What industry is Green Therma in?
Green Therma's product category is Geothermal Heat Services. Its primary akta.pro industry code is EUACAHAE, Closed-Loop Geothermal Power Generation (Advanced Geothermal Systems), with a secondary code of EUAMAEAI, Geothermal Equipment & Component Manufacturing (Turbines, Heat Exchangers, Pumps, ORC Units). Its NAICS code is 221116 and its SIC code is 1389.