POWER September 2023 - S23

SEPTEMBER 2023 | WWW.POWERMAG.COM
Kuester Generating Station in the Upper
Peninsula of Michigan, " said Megan
Reusser, the Hydrogen Technology
manager for Burns & McDonnell, referencing
the other aforementioned
UMERC power plant. " In addition to the
complicated logistics associated with
designing, building, and commissioning
these plants together, the Mihm
site team had to work through heavy
annual snowfall amounts in nearby areas
of over 25 feet. "
Reusser said the company's scope of
work at Mihm for the hydrogen project
" included the design interface with the
existing plant and blending systems,
coordination with the hydrogen supplier
Certarus and engine manufacturer
Wärtsilä, test plan development, and onsite
assistance during the test burn data
collection period. " Reusser, like Ostman,
noted the " great collaboration " among
many companies involved in the hydrogen
test, including Lectrodryer-the hydrogen
safety consultant-and Mostardi
Platt, the emissions testing provider.
" EPRI facilitated project meetings
and supported safety, design engineering,
and test planning activities, "
said Reusser. " EPRI also participated in
the testing and led the assessment of
the engine performance data analysis.
A full test plan was developed and enacted,
and measurements taken were
used to assess the engine's performance
over a range of operating conditions
when using a hydrogen-natural
gas blend. Key parameters measured
included electrical output, efficiency,
and emissions. "
EPRI released a report earlier this
year that said the group's analysis confirmed
the feasibility of blending hydrogen
with natural gas for use in an
existing Wärtsilä engine. The group
wrote that demonstration results from
the Mihm plant showed hydrogen can
be safely and reliably handled and utilized
in engine technology.
Compiling the Data
Wärtsilä officials told POWER that
" performance of the 50SG engine was
measured for the set of investigated
test points, such as output power and
heat rate. " In addition to this, key emis1.
This worker is using a testing wand to collect measurements and other data as part of the hydrogen blending
project at the A.J. Mihm facility. Courtesy: WEC Energy Group
sions like NOx, CO, and total hydrocarbon
(THC) emissions were measured
along with measurements of the gas
composition of the natural gas and the
concentration of hydrogen in the fuel
mix (Figure 1). " As long as the engine
could be tuned without limitations, the
energy efficiency improved with higher
hydrogen-blending ratios, " the officials
said.
Ostman said that during the testing,
" with some engine-control parameter
tuning, all emissions were at par or
lower when co-firing hydrogen compared
to natural gas. Throughout the
test, the engine was compliant with the
air permit for the installation. "
Reusser said of the Mihm test: " The
18-MW reciprocating internal combustion
engine unit was continually monitored
to measure performance, output,
and emissions data. During the testing,
the capability of the Wärtsilä engine
to co-fire hydrogen blends was successfully
demonstrated, showing clear
improvements in carbon emissions,
while staying compliant with nitrogen
oxide emissions. A 95% engine load
was achieved with the 25% by volume
hydrogen blend. "
Reusser noted that the project " was
the first hydrogen power test of a utility-scale,
grid-connected reciprocating
engine generator in the world. Engine
efficiency was not significantly imwww.re-plus.com
pacted
by hydrogen fuel blending, allowing
this class of engine to maintain
its higher levels of efficiency compared
to simple-cycle gas turbines.
Because engines in general have higher
efficiencies, their relative CO2
output
compared to gas turbines will also
be lower, as was the case in this study. "
Ostman emphasized, " There are lessons
learned when conducting testing
campaigns together with customers,
but I would say that the main thing
was the confirmation of how uneventful
these demonstrations can be with
proper planning and good project partners. "
Ostman added that Wärtsilä is
" currently in several active customer
discussions related to similar and even
more long-term demonstrations. "
Ostman told POWER, " It's good to
keep in mind that the [Mihm project]
presents the results from that particular
engine and installation. For other power
plants out there in the world, the results
can be different depending on the
prevailing ambient conditions as well
as the condition of the plant. " Ostman
noted that the Mihm test " demonstrates
the viability of a first step towards lower
carbon emissions, but further steps are
of course later needed if we want to decarbonize
the industry. "
-Darrell Proctor is a senior associate
editor for POWER (@POWERmagazine).
23

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POWER September 2023

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