POWER February 2017 - 29

COMBINED HEAT AND POWER
at Duke University by about 25% " by displacing
the current electricity mix and boilers
currently serving the university. " The
proposed project would be designed with an
island-mode feature, allowing critical campus
loads to be isolated from the grid and
powered by the plant during crises.
Students Raise Concerns
But just as students at MSU took a stand
against coal, some students at Duke University
have objected to the planned CHP
plant. According to a story published by The
Chronicle, the university's student-run newspaper,
there seem to be two main concerns
about the project: The lack of transparency
leading up to the proposal's announcement
and the continued use of fossil fuels to power
the campus.
Duke University President Richard Brodhead
responded to students' apprehensions
about the project in a letter to The Chronicle.
In it, he said the university was pursuing the
project for " energy reliability and security. "
He pointed out that the medical center and research
center " must have a continuous source
of electricity that is impervious to weather
events and other emergencies that can cause
widespread and lengthy power outages. "
Beyond the plant's dependability, Brodhead
underscored the improved efficiency
that CHP plants provide, and he noted that
the technology " has always been a component
of the university's Climate Action Plan,
which calls for carbon neutrality by 2024. "
To ease fossil fuel concerns, Brodhead suggested
that renewable fuel sources would
eventually replace natural gas at the facility.
" We are continuing to discuss the plant using
bio-gas when it becomes commercially
available, as well as the commitment that the
university and Duke Energy would make to
help that occur, " he wrote.
As this story goes into production in late
December, the project still requires approval
by the North Carolina Utilities Commission
(NCUC). Although " very optimistic " about
the prospects, Duke Energy filed a request
with the NCUC on December 1 to suspend
the discovery and procedural dates until after
May 2017 to allow time for the university
to work with stakeholders regarding the
role of CHP in the school's broader sustainability
goals.
The Duke University CHP plant is a firstof-a-kind
project on the Duke Energy Carolinas
system. However, in its application with
the NCUC, Duke Energy noted that it has
been soliciting interest in CHP from large industrial,
institutional, and military customers
since 2015. The company claims that there
are several interested parties, and it suggested
that experience from the Duke University
February 2017 | POWER
5. Duck power. 2G Energy's containerized CHP system uses biogas produced from this
Indiana duck farm's multiple waste streams to supply onsite heat as well as power to the local
grid. Courtesy: 2G Energy
project would benefit all of its future CHP
ventures.
Community and Containerized
CHP
Compared to university projects like MSU's
and Duke's, large-scale renewable CHP projects
are usually driven by policy rather than
economics. But in recent years, there's been
more attention paid to smaller plants that are
designed from the start to provide renewable
energy for its own sake-and these projects
are typically set up for economic reasons,
allowing their owners to capture energy and
heat from waste streams that would otherwise
be lost.
Anne Hampson, project manager with
ICF, told POWER in an interview that much
of the growth in renewable CHP is being
driven by improvements in technology and
standardization that have substantially reduced
the cost of generation. " With some
of the CHP systems that are available in the
market, they can really reduce the capital expenses
for these smaller sites because they
are prepackaged, " she said. " A lot of them are
built into shipping containers so the engine
and heat recovery is all combined. It's really
bringing the cost of those installations down
and opening up a whole new market. "
ICF estimates that about 4,500 MW of
renewable-powered CHP is in operation
across the U.S., Hampson said. This includes
www.powermag.com
traditional large-scale biomass but also an
increasing amount of small-scale generation.
One trend Hampson has seen might be
dubbed " community CHP. " Much as groups
of homeowners and businesses have combined
resources to install centralized solar
(see " Solar Gardens: A Fast-Growing Approach
to Photovoltaic Power " in the May
2015 issue), farms and ranches in a growing
number of areas are working together to build
anaerobic digester systems that serve the surrounding
community and use the produced
biogas to generate heat and power.
" In the past, you saw these mostly in California
and the Northeast, but lately we're seeing
a lot more traction in the Midwest and
even parts of the South. " Again, the primary
driver is the falling cost of " plug-and-play "
CHP systems, which make small-scale biomass
and biogas streams economic to exploit
where they once were not.
One company offering these containerized
CHP solutions is 2G Energy, which is based
in Germany but which has supplied systems
across the U.S. and Canada, mostly in the
500-kW to 2-MW range. It recently built
a 1,200-kW system at a large duck farm in
Middlebury, Ind. (Figure 5). The farm operates
an anaerobic digester using animal waste
and processing plant by-products, as well as
corn silage and other substrates. The three 2G
agenitor 212 generators run on biogas from
the digester. Those generators supply power
29

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POWER February 2017

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