What Combined Energy Technology does

Combined Energy Technology, doing business as Stirling Technologies, is an Athens, Ohio-based private clean energy hardware company (1-10 employees) that develops and sells micro combined heat and power (mCHP) systems built around the proprietary Microgen Stirling Engine. The engine is an external combustion device that converts thermal energy from diverse fuel sources into mechanical work and ultimately electricity, with a claimed global installed base of 7,000+ units, a 50,000-hour engine lifetime, and no reported accidents. The company's commercial product line comprises the BioGen (a biomass-fueled mCHP producing 1 kW electrical and 8.5 kW thermal output, with a patent-pending continuously operating biomass gasifier and claimed carbon-negative biochar sequestration), the mCHP Generator (a natural gas/propane unit producing 1 kW electrical and 6.5 kW thermal at 95% overall efficiency), and an announced landfill gas/methane CHP variant in development. A robust proprietary vortex combustion burner enables the platform to handle contaminated and low-grade fuels (rice husks, wood chips, sawdust, landfill gas, biogas) that damage conventional internal combustion engines.

The company's business model centers on direct hardware sales of these systems, sourced through its website contact forms and a regional beta testing program targeting customers within 60 miles of the Athens, OH headquarters. Pricing is not publicly disclosed and is handled via contact-based quoting. Targeted customer segments include off-grid and remote locations (backwoods cabins, island houses), residential energy supplementers seeking to displace coal electricity (the primary segment), electric vehicle owners seeking clean charging, agricultural users (rice farmers in India), and landfill/methane operators. The company's required off-grid inverter integration with Victron Energy's Microgrid platform is its only disclosed technology partnership.

Strategically, the company competes on the basis of multi-fuel flexibility, claimed 90%+ system efficiency versus ~32.5% average US grid generation efficiency, and biochar-based carbon sequestration as a differentiated environmental narrative. It has demonstrated deployments in India (rice husk irrigation pumps) and the U.S. Northeast (wood chip residential systems). The firm is privately held with no disclosed funding rounds, no revenue figures, no institutional investors, and no executive team details in the available source material, indicating an early-stage commercial profile.

Name

Combined Energy Technology

Legal name

Combined Energy Technology

Website

https://stirling-tech.com

Company type

Private

Operating status

Operating

Headcount range

1–10 employees

Short description

Combined Energy Technology is a private Athens, Ohio clean energy hardware company (1-10 employees) that sells Microgen Stirling Engine-based micro combined heat and power systems (BioGen biomass unit and mCHP Generator gas unit) to residential, off-grid, agricultural, and landfill operator customers via direct sales and a regional beta program.

Ownership category

akta.pro rank

Product category

Micro Combined Heat and Power (mCHP) Systems

NAICS

Biomass Electric Power Generation (221117), Turbine and Turbine Generator Set Units Manufacturing (333611), Electric Power Generation (22111)

SIC

Cogeneration Services & Small Power Producers (4991), Engines & Turbines (3510), Motors & Generators (3621)

akta.pro primary industry

Micro-CHP / Residential CHP (Small-Scale Engine/Stirling/Fuel Cell) (EUACAKAK)

akta.pro secondary industries

Biomass Combined-Cycle & Advanced Power Plants (e.g., BIGCC) (EUAAAGAF), Microturbines, Fuel Cells & Distributed Generation Prime Movers (IMAHAFAH), Microgrid EPC, Integration & Commissioning (Design-Build, Interconnection) (EUAFAJAI)

Keywords

• Micro combined heat and power
• Stirling engine systems
• Biomass gasification
• Distributed energy generation
• Micro cogeneration

Headquarters

HQ city

Athens

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Supply Chain, Personnel, Marketing or Sales, Operations

Revenue model

1. BioGen mCHP System Sales: Sale of biomass-fueled combined heat and power systems for electricity and thermal energy generation. Systems include the BioGen (biomass-fueled) and mCHP Generator (natural gas/propane). Revenue derived from hardware sales, installation, and ongoing maintenance services.
2. mCHP Generator System Sales: Sale of natural gas and propane fueled micro combined heat and power systems. The mCHP Generator produces 1 kW electricity and 6.5 kW thermal output for on-site power and heat generation.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels2 records

Core offering

Combined Energy Technology manufactures and sells micro combined heat and power (mCHP) systems built around the patented Microgen Stirling Engine. Its commercial products, the BioGen (biomass-fueled) and the mCHP Generator (natural gas/propane-fueled), generate on-site electricity (1 kW) and usable thermal energy (6.5–8.5 kW) at overall efficiencies above 90%, with the BioGen additionally producing biochar as a soil amendment for carbon sequestration.

Product overview

Combined Energy Technology offers a portfolio of micro combined heat and power (mCHP) systems built around the patented Microgen Stirling Engine. The product lineup consists of two primary commercial offerings: the BioGen (biomass-fueled system) and the mCHP Generator (natural gas/propane-fueled system), both delivering on-site electricity and thermal energy with overall efficiencies exceeding 90-95%. A third product—the Stirling Fired CHP System for landfill gas/methane—is currently under development. All systems leverage external combustion Stirling engine technology to provide clean, efficient power generation suitable for off-grid and grid-tied installations.

Differentiator

Problem solved

Functional benefit

Products and services

• BioGen

Quantifiable outcome

• 95% energy efficiency for mCHP Generator (natural gas/propane), over 90% for BioGen (biomass)
• +4 more outcomes

Named customers2 records

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature4 records

Scale indicators4 records

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Viessmann: Large European heating OEM offering the ecoPOWER micro-CHP unit alongside boilers, heat pumps, and broader HVAC; addresses the same residential CHP buyer as CET but as part of a much wider product portfolio.
• Honda (Honda Power Equipment / Home Energy): Honda has historically offered micro-CHP and home energy products; competes with CET in residential on-site power and heat applications, supported by a much larger manufacturing and dealer network.
• Bloom Energy: US-based fuel cell power systems provider with commercial-scale solid oxide installations; competes with CET for on-site, low-emission heat and power but at much higher power outputs and with a different technology stack.
• 2G Energy: German manufacturer of gas engine CHP systems from small commercial to multi-MW scale; overlaps with CET on gas-fueled combined heat and power but operates at substantially larger unit sizes and volumes.

Direct peers

• Microgen Energy: Supplier of the Microgen Stirling Engine that CET's products are built around; targets the same residential micro-CHP and off-grid segments with directly comparable 1 kW-class Stirling systems.
• EC POWER: Danish manufacturer of compact Stirling-based micro-CHP units for residential and small commercial customers; competes head-to-head with CET in the sub-10 kW combined heat and power category.
• Baxi SenerTec: German manufacturer of the Dachs micro-CHP unit, one of the most deployed residential Stirling-engine CHP systems in Europe; directly comparable to CET's BioGen and mCHP Generator offerings.

Regional players

• Aisin (Toyota Group): Japanese automotive supplier that developed residential micro-CHP systems (formerly through Toyota and Aisin Seiki), competing with CET in residential on-site power and heat primarily in the Japanese market.

Emerging players

• Ceres Power: UK-based developer of solid oxide fuel cell (SOFC) technology with a focus on micro-CHP and distributed power, including residential applications; competes with CET for the same decarbonized on-site generation use case via a different prime mover technology.

Others

• Victron Energy: Required inverter/integration partner for CET's CHP system during the beta phase; relevant ecosystem peer whose microgrid components CET currently depends on for off-grid and grid-tied functionality.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat3 records

Key risks5 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/sterling-tech

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Combined Energy Technology