POWER February 2016 - 20

COMBINED HEAT AND POWER
Bakersfield Biomass
California is often thought of as an oasis
of environmentalism and renewable energy.
Although both are deeply embedded
in the Golden State, California also has a
robust oil and gas sector, most of it concentrated
in the inland areas of the southern
half of the state. Kern County and its
county seat, the city of Bakersfield, have
long been the capital of California's oil
business.
Making that sector more environmentally
friendly has long been a goal of state
regulators and environmental groups. One
such project, the 44-MW Mt. Poso Cogeneration
Plant-shown in the header photo-came
to fruition a few years ago.
The Mt. Poso plant has been around
for decades, but until recently, it ran on
a combination of coal, petroleum coke,
and shredded tires-not the most ecofriendly
mix. Plant owner MacPherson
Energy Corp. uses steam from the plant
for operations in its adjacent oil field,
while water from the oil field is used for
produced steam and plant cooling. Emissions
from Mt. Poso put the plant in the
sights of state regulators, who slated it
for closure in the 2000s.
in part because of its ability to promote grid
resiliency, and the state gets 57% of its total
distributed generation (DG) from CHP. The
state's Reforming the Energy Vision (REV)
strategy, spearheaded by Governor Andrew
Cuomo, is expected to provide an even greater
boost to CHP. The plan seeks a 40% reduction
in state greenhouse gas emissions, 50%
renewable generation, and a 23% decrease in
building energy consumption-all goals that
CHP can help meet.
As part of REV, the state announced in
September that it is aiming to increase the
number of CHP projects in New York by
10% through $258 million in public and
private funding of 53 separate projects (totaling
about 200 MW) that are already in
development. The New York State Energy
and Research Development Authority is providing
$41 million of the total, with the balance
coming from private investors. In part
because of experiences during Superstorm
Sandy, when CHP helped numerous institutions
keep the lights on (for one example, see
the story on the New York University [NYU]
Cogeneration Plant, a POWER Top Plant, in
the September 2014 issue at powermag.com),
many of these projects are part of microgrids,
20
MacPherson Energy opted instead to
convert the plant to burn biomass. It
formed a partnership with DTE Energy Services
to undertake the conversion, which
began in November 2010. Limited operations
began the following year, and the
project was declared complete in February
2012. While plant capacity was reduced
from 55 MW to 44 MW, the emissions profile
was substantially improved.
MacPherson and DTE are equal owners
in the new plant, which burns biomass
from urban and agricultural wood waste
(construction, tree trimmings, and agricultural
sources). The $34 million project
not only preserved 30 existing jobs in an
economically challenged area, but it also
created eight new ones at the site and
spurred growth for several area companies
supplying biomass fuel.
The project was also a win for Pacific
Gas & Electric (PG&E), which signed a 20year
power purchase agreement for the
plant's electricity. Conversion to biomass
qualified the plant as a renewable power
generator, helping PG&E meet its obligations
under California's ambitious renewable
portfolio standard.
including a $37 million, 15-MW system at
Columbia University.
Other states are also making concerted
drives to boost CHP.
Minnesota in 2013 began an initiative
designed to study how CHP could help
meet the state's renewable portfolio, energy
conservation, and GHG reduction goals.
The process, funded by a U.S. Department
of Energy grant and conducted through
stakeholder meetings in 2013 and 2014,
produced a detailed CHP Action Plan that
was released in October 2015. It builds on
previous studies that showed, among other
things, that the state could easily double its
CHP capacity and had technical potential
of four times the current 961 MW. Other
findings during the process were that most
stakeholders felt current rates and utility
business models were not favorable for
CHP in Minnesota and that existing incentive
programs were not sufficient.
In the action plan, the state lays out an
ambitious, multifaceted plan to help advance
CHP, including policy and rate reform, identifying
the best CHP opportunities, and public
outreach and education. One concern is how
CHP fits into the state's existing Conservation
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Improvement Program, and the plan seeks to
clarify and revise evaluation criteria to ensure
worthwhile CHP projects are eligible. The
process of identifying potential projects will
start with existing public facilities that could
employ CHP, such as universities and wastewater
treatment plants, and develop plans for
CHP implementation. The plan also makes
an aggressive commitment to seeking out and
exploiting existing CHP support mechanisms
and incentives. Policy and rate reform, naturally,
will take longer, but the plan begins a
process to formulate a specific list of changes
that could be implemented.
New CHP Tech
Microgrids powered by CHP are drawing
increasing attention because of their extra
resiliency. Typically, though, these have
been large, megawatt-scale systems such as
the NYU and Columbia projects. Now, advances
in software and data processing are
enabling owners of smaller CHP systems to
aggregate them into a single, flexible, dispatchable
resource. While not necessarily a
true microgrid, these systems have many of
the same properties.
Redwood City, Calif.-based firm Autogrid
has begun marketing what it calls
Software-Defined Power Plants, aggregated
DG that functions as a single system on the
grid using its Predictive Controls software.
This approach allows large customers to reduce
their demand charges, to participate in
utility demand response programs, or trade
directly in electricity markets in ways that
may not be available or feasible for small
systems operating separately. The first such
virtual plant was rolled out in November in
the Netherlands and Belgium in partnership
with Eneco Group, and involves 100 MW of
resources, including several customer-sited
CHP systems. Autogrid has also partnered
with Italian firm Electro Power Systems
(EPS) to integrate its hydrogen-based energy
storage system.
EPS's technology deserves special mention
because, in addition to storing energy as
hydrogen via electrolysis, the units can then
release the hydrogen for use as fuel for CHP.
While still new, the technology holds the
promise of integrating storage and renewable
CHP into a single system.
Smaller turbines and microturbines
have been used for CHP for many years,
but these typically require pairing with
a separate heat-recovery system. Portsmouth,
N.H.-based FlexEnergy, however,
is introducing a CHP system that combines
a 330-kW microturbine with an integrated
onboard hot water heat exchanger. According
to Doug Demaret, FlexEnergy's vice
president of sales and marketing, comPOWER
| February 2016
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POWER February 2016

Table of Contents for the Digital Edition of POWER February 2016
