Norway-based Techouse has completed testing of a compact once-through steam generator (COTSG), designed to reduce fuel consumption and CO₂ emissions from power and heat production processes on offshore installations.

The joint industry project (JIP) is supported by TotalEnergies, Equinor and SINTEF Energy Research.

Following funding from the Norwegian Research Council, the JIP developed the lightweight COTSG. Trials took place at the Sustainable Energy test center for new and green energy carriers at Stord, western Norway.

Reducing emissions from offshore power generation

An analysis revealed that gas turbine combined cycle solutions on floating and fixed offshore installations can bring a 22-25% reduction in CO₂ emissions compared to conventional gas turbine solutions.

Cutting fuel use and CO₂ emissions by 25% could reduce emissions by between 50,000 and 150,000 metric tons annually per combined-cycle power plant installation, the developers claim.

Platform power generation remains one of the largest sources of operational emissions offshore. While electrification from shore is being adopted in select regions such as the Norwegian Continental Shelf, many offshore facilities worldwide continue to rely on gas turbines for power and heat generation, driving interest in technologies that improve efficiency and reduce fuel consumption.

With combined cycle, heat from the exhaust of the gas turbines is used to generate superheated steam, which is harnessed to generate additional power in a steam turbine.

But present OTSG solutions are restricted by the weight and size of the heat recovery equipment, with deck space and weight capacity already constrained on many offshore oil and gas installations.

Potential applications could include fixed production platforms, FPSOs and other offshore facilities that depend on gas-turbine-based power generation and are seeking lower-emission operating strategies.

Weight and topsides space constraints have long limited deployment of combined-cycle systems offshore, particularly on floating production facilities and mature fixed platforms where additional equipment can have significant design and operational impacts.

“The JIP set out to design, build and test an OTSG that is lighter and smaller than current solutions, enabling it to be installed on even more offshore installations," Techouse CTO Pål Kloster said. “We have previously achieved the two first objectives of making it lighter and smaller, thereby more competitive. We have over the past few months tested the generator to ascertain its robustness and thereby fully verify its commercial potential.”

Testing targets long-term offshore deployment

The test program covered performance, vibrations and fatigue, including thermal fatigue, and stress testing, to determine if the steam generator could withstand a minimum 30-year lifecycle.

“The test has delivered positive results against the key test parameters, and we are now proceeding with a comprehensive analysis of the logged test data,” Kloster added.

The testing campaign was designed to verify that the compact steam generator could meet offshore reliability requirements while maintaining its reduced weight and footprint.

Techouse said a commercial version of the COTSG could be introduced later this year. Beyond commercialization, the company said it plans to pursue projects integrating the technology with carbon capture systems on offshore platforms.