Hydrogen

WEC Energy Group plans hydrogen power pilot using reciprocating engines

WEC Energy Group announced a pilot project to test co-firing hydrogen with natural gas at one of its Michigan power plants.
WEC Energy Group plans hydrogen power pilot using reciprocating engines

WEC Energy Group announced a pilot project to test co-firing hydrogen with natural gas at one of its Michigan power plants.

During the pilot project, hydrogen and natural gas will be mixed up to a 25/75 percent blend to power one of the generating units that serves customers of Upper Michigan Energy Resources, a WEC energy subsidiary. The units use reciprocating internal combustion engines, which were manufactured by technology company Wärtsilä and began service in 2019.

Reciprocating engines convert pressure into rotating motion using pistons, while gas or combustion turbines use the pressure from the exploding fuel to turn a turbine.

WEC is partnering with the Electric Power Research Institute (EPRI), which will lead the technical implementation of the project and share results to further educate the energy industry about how to successfully use hydrogen for power generation to support reducing carbon emissions.  

WEC described the hydrogen power pilot as among the first of its kind in the U.S.

“The potential of adding hydrogen as a clean generating fuel to our fleet of dispatchable plants is an important step as we bridge to a bright, sustainable future,” said Gale Klappa, executive chairman

WEC Energy Group has a goal of net-zero carbon emissions from electric generation by 2050 and net-zero methane emissions from natural gas distribution by the end of 2030.

In 2020, Wärtsilä said it was developing the combustion process in its gas engines to enable them to burn 100% hydrogen fuel. At the time it had tested its engines with blends of up to 60% hydrogen and 40% natural gas.

In addition to hydrogen, it said other potential renewable fuels also were being studied for future applications, that its engines were already capable of combusting 100% synthetic carbon-neutral methane and methanol.

The U.S. Department of Energy identifies two primary reciprocating engine designs relevant to stationary power generation applications: the spark ignition Otto-cycle engine and the compression ignition Diesel-cycle engine.

The essential mechanical components of the Otto-cycle and Diesel-cycle are the same. Both use a cylindrical combustion chamber in which a close fitting piston travels the length of the cylinder. The piston connects to a crankshaft that transforms the linear motion of the piston into the rotary motion of the crankshaft. Most engines have multiple cylinders that power a single crankshaft.

The main difference between the two cycles is the method of igniting the fuel. Spark ignition engines (Otto-cycle) use a spark plug to ignite a pre-mixed air fuel mixture introduced into the cylinder. Compression ignition engines (Diesel-cycle) compress the air introduced into the cylinder to a high pressure, raising its temperature to the auto-ignition temperature of the fuel that is injected at high pressure.

For combined heat and power applications, most installations use four-stroke spark ignition engines, the Energy Department said. Reciprocating engines are characterized as either rich-burn or lean-burn. Rich-burn engines are operated near the stoichiometric air/fuel ratio, which means the air and fuel quantities are matched for complete combustion, with little or no excess air.

In contrast, lean-burn engines are operated at air levels significantly higher than the stoichiometric ratio. In lean-burn engines, engine-out NOx emissions are reduced as a result of lower combustion chamber temperatures compared to rich-burn engines. 

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