Syntholene Energy says it has finished construction of its geothermal-integrated Solid Oxide Electrolyzer Cell demonstration facility in Húsavík, Iceland—around six months ahead of plan and under budget.
The milestone marks a transition from development into live operations for what the company describes as a first-of-its-kind energy system integrating geothermal heat with high-temperature electrolysis for hydrogen production.
“Completing a first of its kind energy facility ahead of schedule and under budget is rare,” stated Dan Sutton, Chief Executive Officer of Syntholene.
“Achievement of this milestone reflects the quality of our engineering team, project partners, and execution discipline. Syntholene has now graduated from concept and prototyping into real-world operations. Over the next few months of effects testing, we seek to demonstrate practically that geothermally-integrated SOEC hydrogen production can materially improve the economics of synthetic fuel.”
The Demonstration Facility is designed as the company’s first fully integrated field deployment of its thermal-hybrid architecture, and will serve as a testbed for operational validation and performance data collection.
Syntholene expects testing to begin shortly, with initial efficiency and technoeconomic results targeted for publication as early as Q4 2026.
According to the company, the facility was completed just 69 days after permit issuance, encompassing fabrication, delivery, installation, and integration of key systems. These include its proprietary Thermal Coupling Heat Exchanger system, SOEC module, water treatment systems, instrumentation and controls, and full balance-of-plant infrastructure.
The Thermal Coupling Heat Exchanger system alone was fabricated in 42 days, while factory acceptance and commissioning of the SOEC module were completed ahead of schedule.
The company says the project is intended to demonstrate potential gains from combining geothermal heat with high-temperature electrolysis to produce low-cost hydrogen, a key input for synthetic fuels. It argues that this approach could reduce electricity demand compared with conventional electrolysis by substituting part of the energy input with geothermal heat.
Testing will focus on validating continuous integration between geothermal heat systems, hydrogen production, thermal recovery loops, and supporting infrastructure. Data from the facility will feed into future engineering optimization, technoeconomic modelling, commercial project development, and financing discussions.
“Syntholene’s next objective is to generate operational data from this real geothermally-integrated infrastructure, validating the impact of low-cost geothermal heat integration with high-temperature electrolysis. If successful, we believe this could represent a meaningful advancement toward cost-competitive synthetic aviation fuel.”
