| Waste Not, Want Not
by David Pescovitz
the near future, the heat that warms your apartment in the winter
may be piped in from the dry cleaner next door. According to UC
Berkeley researchers, harnessing the "waste" heat that's
currently vented out the back of turbines and generators could
help ease our energy bill woes by doubling the effective efficiency
of fossil fuel combustion in a wide range of power plants.
Kammen, professor in the Department of Nuclear Engineering,
researches an alternative energy technology called "combined
heat and power" (CHP).
This alternative to gas or electric heaters is part of an energy
technology called "combined heat and power" (CHP), where
both the waste heat as well as the electricity is captured from
the combustion of fuel. The CHP effort is being driven by a growing
interest in distributed power generation, the integration of small
power plants into buildings, so individuals and businesses can
produce their own electricity instead of buying it from centralized
"Building a market for waste heat improves the economics of
distributed power generation," says Daniel Kammen, professor
in the Department of Nuclear Engineering, the Energy and Resources
Group (ERG), and
the Goldman School of Public Policy.
In the United States, more than 60 gigawatts of power are generated
via CHP, with a Department of Energy (DOE) goal of 92 gigawatts
by 2010. After all, CHP makes perfect economic sense. For example,
a gas turbine requires approximately 1000 megawatts of input fuel
to make 333 megawatts of electricity. That means the turbine's
fuel efficiency -- the ratio of the useful energy obtained to the
fuel it burns -- is just 33 percent. Capturing the heat that's
generated during the combustion process ups the unit's efficiency
70 percent in some cases.
With some shifts in policy and the design of infrastructure to
transfer waste heat, Kammen is convinced the U.S. building industry
could put CHP and distributed power generation to more widespread
use here as well. For example, take a mini-mall where a dry cleaner
and restaurant both produce a great deal of heat.
"All of that heat currently vents out the windows or the backs
of turbines and generators," Kammen says. "If the mini-mall
could sell the heat to an apartment complex next door, it improves
the mall's economics and decreases our overall need for fossil
fuels to make heat."
In that scenario, Kammen envisions public utilities acting as the
middleman, connecting heatsellers with buyers. It's a model that's
already been proven to work by the Danish National Power Utilities,
among others. Indeed, heating homes with the waste heat from large
and small CHP power plants, like those at industrial facilities,
is already commonplace in many European towns, Kammen says.
"The utility can even work the deal so that their income is
a percentage of their customers' savings over a period," Kammen
kind of performance-based contract gives the utility a revenue
stream, an incentive to do a good job, and provides a way for customers
to participate in CHP programs without much up-front cost."
solar panels, such as these, could be used to produce
hydrogen to power a fuel cell vehicle
Peg Skorpinski photo
While there are plenty of lessons to be learned from European CHP
efforts, importing their approach isn't so easy, Kammen says. For
instance, some regions in Europe take CHP opportunities into account
during urban planning. Physically connecting heat sellers and buyers
in this country's urban sprawl environments is much more difficult.
The aim of a new DOE-funded partnership between UC Berkeley, the
California Energy Commission, UC Irvine, and San Diego State University,
is to get a handle on the viability of widespread CHP in this country.
Under the direction of Dr. Timothy Lipman, executive director of
Berkeley's Center for Interdisciplinary Distributed Energy Research
(CIDER) and an ERG research associate, the Southwest CHP Regional
Application Center (SWAC) is charged with studying and promoting
CHP in the southwestern United States.
SWAC effort spans engineering, economics, and public policy. For
example, students in Kammen's Renewable
and Appropriate Energy Laboratory are developing novel technologies
for heat conduction along with new power generators -- from fuel
cells to "greener" external combustion engines. Meanwhile
though, the DOE grant calls for the researchers to act as "a
conduit of information to the private sector," Kammen says.
you think the United States will embrace the alternative
called "combined heat and power" (CHP)?
want to hear from you...
To that end,
Kammen, Lipman and their colleagues are assessing the feasibility
of CHP systems for several large industrial facilities,
examining regulatory policy, and beginning outreach to the private
sector to encourage a shift in the "energy economy."
"Hopefully once we get the story out, building and industry
will see the opportunities," Kammen says. "Combined heat
and power is good economics and contributes to energy independence."
Renewable and Appropriate Energy Laboratory (RAEL)
Center for Interdisciplinary Distributed Energy Research (CIDER)
State project promotes using waste heat from power generation
to heat and cool buildings by Robert Sanders (campus
Power of Distributed Power by David Pescovitz (Lab Notes)
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