The technology group Wärtsilä and WEC Energy Group have successfully tested the capabilities of a Wärtsilä engine running on 25 vol% hydrogen-blended fuel. The tests, which were completed in October 2022, were conducted at WEC Energy Group’s 55 MW A.J. Mihm power plant in Michigan using an unmodified Wärtsilä 18V50SG engine.

The Wärtsilä 50SG is a four-stroke, spark-ignited gas engine generating set.

Throughout the testing period, the Wärtsilä engine continued to supply power to the grid. This is the largest commercially operated grid-connected flexible balancing engine ever to run on a hydrogen fuel blend, representing therefore a world-first achievement.

The Electric Power Research Institute (EPRI) also participated in the tests and led the assessment of the engine’s performance during the testing. In a recently released report, EPRI’s analysis confirmed the feasibility of blending hydrogen (H2) with natural gas for use in an existing Wärtsilä engine. The demonstration results also showed hydrogen can be safely and reliably handled and utilized in engine technology.

During three days of continuous testing, the capability of the engine to co-fire hydrogen blends was successfully demonstrated, showing clear improvements in engine efficiency and reduced greenhouse gas emissions, while staying compliant with NO_x emissions.

A 95% engine load was achieved with the 25 vol% H₂ blend. This verifies the fuel flexibility of Wärtsilä engines without compromising efficiency. Further testing showed that with a 17 vol% H₂ blend, a 100% engine load was attainable.

The EPRI report states that this class of engines can therefore maintain its higher efficiency compared to simple-cycle gas turbines. Because engines in general have higher efficiency, their relative CO₂ output compared to turbines will also be lower, as was the case in this study.

As utilities increase the utilization of renewable energy assets, such as wind and solar, opportunities exist to produce hydrogen for long-term energy storage from excess renewable energy. As a fuel, hydrogen burns without producing any carbon species including CO₂. Hydrogen electrolyzer manufacturing capacity sits at nearly 8 GW/yr today, but it could exceed 60GW/yr by 2030 based on industry announcements.

Among other sustainable fuels, hydrogen will be critical to reaching net zero emissions, and is expected to contribute 20% of the total abatement of CO₂ needed in 2050. However, today’s global energy industry is not built for the adoption of pure hydrogen as a secure power source. Significant investment into market-ready engines which can run on sustainable fuels is therefore crucial in supporting the transition to net-zero, Wärtsilä said.