POWER October 2015 - 36

TOP PLANTS
Spiritwood Station, Spiritwood,
North Dakota
Owner/operator: Great River Energy
Courtesy: Great River Energy
Recent news has focused on the decline of the coal-fired power industry, but this
highly efficient combined heat and power plant offers one template for keeping coal
generation viable. Although electricity markets remain challenging, partnering with
steam customers can help stabilize revenue.
Aaron Larson
C
ombined heat and power (CHP), also
known as cogeneration, has been in use
in the U.S. for more than 100 years, but
many experts believe it is still an underutilized
resource. CHP is the simultaneous generation
of useful heat and power from a single fuel or
energy source at or close to the point of use.
CHP captures energy that would normally be
lost in power generation and uses it to provide
heating and cooling, or process energy, making
CHP systems much more efficient.
The Department of Energy says that CHP
accounts for about 8% of current U.S. generating
capacity. Although that is not significantly
lower than the global average of about
10%, the International Energy Agency says
CHP has the potential to command a 15% to
20% share of total electricity generation in the
U.S. by 2030. But, it suggests that a thoughtful,
well-implemented policy intervention is
required to facilitate the expansion. Although
President Obama signed an Executive Order
in August 2012 establishing a national goal
of adding 40 GW of CHP capacity by 2020,
very little progress toward that goal has been
achieved three years later.
A Combined Heat and Power Success
Story
However, there is one shining example of
new CHP capacity that was added in North
36
Dakota when the Spiritwood Station became
fully operational on November 1, 2014. The
plant is located about 10 miles east of Jamestown
on a 100-acre site adjacent to the Cargill
Malt facility (Figure 1) and the Dakota
Spirit AgEnergy biorefinery. Spiritwood Station
is owned and operated by Great River
Energy (GRE) and replicates the success the
company has experienced at its Coal Creek
Station, which supplies steam to the Blue
Flint Ethanol biorefinery for process energy
and to dry distillers grains.
Although the plant's electrical capacity
is only 99 MW, the station more than makes
up for its small size through high efficiency.
According to the U.S. Energy Information
Administration, average efficiency for U.S.
coal-fired power plants is under 33%, but
Spiritwood, with its key industrial partners
operating at full capacity, achieves about
60% efficiency. By design, it could reach up
to 66% efficiency as more steam users are
added, which GRE is actively pursuing.
" The Spiritwood Energy Park is designed
with the ability-the land, the rail service,
the roads, etcetera-to be able to handle additional
industrial installations, and our business
development group is working closely
with the Jamestown/Stutsman Development
group to attract additional partners, " John
Weeda, director of North Dakota generation
www.powermag.com
for GRE told POWER. " We have additional
steam available, so if some of those partners
need steam, we would be glad to provide for
their steam needs. "
An In-House Project
Unlike many projects of this magnitude,
GRE chose not to use an engineering, procurement,
and construction contractor; instead,
it handled overall project management
in-house. The company hired engineers and
worked with them on the procurement process.
It also contracted directly for construction
management.
" We like that kind of a project. It gave us
direct control and involvement, " Weeda said.
" One of the benefits we find of that is the
transition from construction into your startup
phase of the project goes quite well when we
take that approach. "
Babcock & Wilcox Power Generation
Group Inc. supplied the plant's boiler, which
utilizes internal recirculation circulating fluidized-bed
(CFB) technology. Some advantages
of this technology include reduced SO2
emissions due to the addition of limestone
to the circulating bed, lower NOx emissions
as a result of low furnace temperatures and
staged combustion, and improved collection
efficiency through the use of a two-stage solids
collection system.
POWER | October 2015
http://www.powermag.com
POWER October 2015

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