Test shows hydrogen blending slightly reduces gas power plant emissions

March 24, 2023
By Julian Spector

GE planning for multiple larger-scale demonstrations starting in 2024

A Wärtsilä 50SG reciprocating engine like this unit was used in the test. (Wärtsilä)

A gas plant in Michigan successfully burned a mix of hydrogen and methane to generate electricity in a recent field test. That’s an important proof point for efforts to turn hydrogen into a pillar of the clean energy transition — but mass adoption of the fuel is still far from certain.

Fossil gas still provides more electricity in the U.S. than any other source, but carbon-free wind and solar power are growing much faster. Those resources need help to deliver power 24/7. Some countries and companies have pinned their hopes on hydrogen, which can be synthesized with clean electricity through electrolysis, stored and then used for carbon-free energy.

Boosters of clean hydrogen say the light, colorless gas can decarbonize everything from home heating and cooking to power plants to long-distance trucking. These claims range from preposterous to plausible, but none of them have been borne out by widespread real-world adoption. Few have even been demonstrated at small scale. That’s where the new testing comes in — Wärtsilä calls the test a “world-first achievement,” since it’s the largest test using this type of power equipment at an active power plant.

Power producer WEC Energy Group blended hydrogen with the natural gas it normally burns in a 19-megawatt Wärtsilä reciprocating engine at the A.J. Mihm plant in Michigan’s Upper Peninsula. The participants fired up the engine at different levels and with different amounts of hydrogen in the mix to measure how it performed and how emissions changed. The Electric Power Research Institute, a utility-funded research nonprofit, was on hand to document the findings, and it published a report on the test earlier this month.

Notably, the companies wanted to test what happens when existing, commercially operating engines burn some hydrogen: “No mechanical modifications that would impact the engine performance were made to the engine,” the EPRI report notes. That makes the findings relevant to the broader population of currently operating plants, though reciprocating engines are just one of the common types of gas generator.

The basic finding is that hydrogen blending works, up to a point.

A company called Certarus successfully set up two trucks filled with pressurized, cleanly produced hydrogen that was pumped through a temporary blending rig into the power plant. The engine then burned the blended gases to make electricity, and its efficiency stayed effectively unchanged compared to a pure natural-gas burn. This was all done without incident, because, as the report narrates in stirring prose, “both written and verbal forms of communication were employed to ensure safety was maintained.”

The study was limited in scope, however. The participants only tested up to a 25 percent blend by volume. That level was dictated by the safety specifications for this type of engine, a Wärtsilä spokesperson told Canary Media. A model designed to use 100 percent hydrogen is planned to be offered for sale in 2026.*

At that 25 percent level, the engine maxed out at 95 percent of its normal capacity. When burning a 25 percent hydrogen mix, carbon dioxide emissions only dropped by around 9 or 10 percent in the various tests (a similar test at a GE combustion turbine in Long Island reduced carbon emissions by 14 percent when firing a mix of 35 percent hydrogen).

WEC has promised to cut its carbon emissions from electricity production by 60 percent in 2025 and 80 percent in 2030, compared to a 2005 baseline. An optimistic read on this experiment would be that WEC now knows it can notch easy incremental carbon reductions for those fast-approaching deadlines, without sacrificing performance or paying for expensive engine overhauls.

As with anything hydrogen-related, it won’t be so easy. Though WEC could avoid the expense of modifying its engines, it would still need to pay for the hydrogen and blending equipment, and weigh those costs against the fairly marginal emissions benefits. (Update: A spokesperson for WEC told Canary Media that the company does not have immediate plans to adopt hydrogen blending into its power production operations.)

Moreover, mass adoption of clean hydrogen blending would require access to a steady supply of clean hydrogen, which is hard to come by at this stage. The Department of Energy notes that 95 percent of U.S. hydrogen production today derives from refining methane; that makes it a major greenhouse gas emitter.

It goes without saying that cutting 10 percent of emissions from power generation won’t get WEC to its 60 percent reductions. Higher levels of blending may be possible, but that still needs to be proven, and it may require greater degrees of modification. At best, this technique could work alongside other tools like renewables and energy storage to achieve the company’s goals. Indeed, WEC is already working on testing a novel long-duration energy storage technology from CMBlu Energy, another way to deliver clean power on demand (without burning anything).

The test, in other words, pushes hydrogen one small step forward in a long and uncertain journey toward relevance to the clean power system.

*Correction: This article originally stated that Wärtsilä plans to produce an engine that can run on 100% hydrogen by 2025. The target date is 2026. We regret the error.

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