DOE: Combined Heat and Power a compelling but underutilized source of energy efficiency
The U.S. Department of Energy’s Oak Ridge National Laboratory just put out a report on the potential of combined heat and power (CHP) deployments in the United States and has concluded that it is one of the “most proven and effective near-term energy options” available to reduce CO2 emissions, improve energy security, relieve grid congestion, make industry more competitive, and create green-collar jobs.
CHP can provide an immediate solution to pressing energy problems. CHP is one of the most promising options in the US energy efficiency portfolio. It is not a single technology but a group of technologies that can use a variety of fuels to provide reliable electricity, mechanical power, or thermal energy at a factory, university campus, hospital, or commercial building—wherever the power is needed. CHP’s efficiency comes from recovering the heat that would normally be wasted while generating power to supply the heating or cooling needs of the user. By capturing and utilizing waste heat, CHP requires less fuel than equivalent separate heat and power systems to produce the same amount of energy services. Because CHP is located at or near the point of use, it also eliminates the losses that normally occur in the transmission and distribution of electricity from a power plant to the user.
The report finds that current CHP generating capacity in the United States exists at 3,300 sites and amounts to 85,000 megawatts, or nearly 9 per cent of total U.S. capacity. In 2006 actual electricity production amounted to 506 billion kilowatt-hours, or more than 12 per cent of total U.S. power generation. According to the report:
If the United States adopted high-deployment policies to achieve 20 per cent of generation capacity from CHP by 2030, it could save an estimated 5.3 quadrillion Btu (Quads) of fuel annually, the equivalent of nearly half the total energy currently consumed by US households. Cumulatively through 2030, such policies could also generate $234 billion in new investments and create nearly 1 million new highly-skilled, technical jobs throughout the United States. Emissions could be reduced by more than 800 million metric tons (MMT) per year, the equivalent of taking more than half of the current passenger vehicles in the US off the road. In this 20 per cent scenario, over 60 per cent of the projected increase in CO2 emissions between now and 2030 could be avoided.
Those who follow this and other greentech or climate blogs probably appreciate the potential of waste-energy recovery and the enormous contribution it could make to reduce C02 emissions, but it’s good to see the DOE coming out so strongly in favour of this option. Now, the challenge both in the United States and Canada is to convince politicians that this is low-hanging fruit that should be pursued immediately. If fact, any stimulus package should specifically include a focus on helping industry become more efficient by helping fund CHP projects.
Tags: CHP, energy efficiency, energy recovery
Tyler Hamilton is a business columnist for the Toronto Star, Canada's largest daily newspaper. In addition to this Clean Break blog, Tyler writes a weekly column of the same name that discusses trends, happenings and innovators in the clean technology and green energy market. This blog is a personal project started in April 2005. It is not an official blog of the newspaper.
Kawanabe’s statement is annoying though....
December 3rd, 2008 at 7:09 pm
There’s only one thing that reduces the practicality of CHP on a domestic scale: noise.
I’ve puzzled for some time over the absurdity of burning virgin fuel (natural gas in our case) to produce low-grade heat in order to make a house habitable in winter. There is just so much low-grade heat produced as waste… but not in the right place.
The power station 300km away that produces electricity to light my lights and run my fridge releases plumes of steam and torrents of warm water from its cooling towers. But it’s wasteful enough getting the electricity from there to here, let alone the low-grade heat.
My not-really-a-plan was to repurpose an old car engine to heat my house. Shaft power from the engine would turn a generator to produce electricity; coolant would run to a remote “radiator” in my heating ducts. A heat exchanger on the exhaust could also reclaim heat. The engine and coolant hoses could be insulated to ensure all “waste” heat was rejected through the coolant into the house.
It’s not especially difficult to run a spark-ignition engine on natural gas, especially if it is to provide steady-state power with no throttle response required. Efficiency of the engine would be quite irrelevant. If it’s running efficiently it will produce more shaft power (electricity) and less heat, if it’s running inefficiently it will produce more heat and less electricity. Either option is better than my existing furnace which produces all heat and no electricity – the limit case of an inefficient generator.
Emissions are a consideration, but not a blocker. We’re already burning gas for domestic heating in cities, so as long as we maintain a similar quality of combustion for similar grade of emissions there will be no big change.
Aside from time (so many projects so little time), the main blocker to this plan is the noise of the engine. I don’t want a piston engine droning away under my house. A stationary engine running at a fixed speed could be silenced more effectively than in a car, but it would be very difficult to muffle enough to be unnoticeable at 3am. The engine needs to be close to the house to make effective use of the waste heat (long coolant hoses from a distant generator shed would lose most of the heat en route, even if well insulated – an inherent problem with low-grade heat).
Domestic-scale CHP would be a great step forward in efficiency, but would require some serious thought in terms of noise. Nobody wants to live next door to a power station, for the same reason that they wouldn’t want a domestic-scale power station in their basement.
December 4th, 2008 at 2:34 pm
Like you said at the end, a lot of folks who read this blog know about waste energy recovery, but in the U.S., few people do, including the experts. I’m associated with Recycled Energy Development, probably the leading CHP company here in the States. Actually, by our calculations, cutting greenhouse gases by 20% would be the equivalent of removing EVERY car from the road, not half. Either way, there’s an awful lot of potential here, mainly low-hanging fruit.
December 4th, 2008 at 9:28 pm
I’m retired now and no longer own my own home. My wife and I owned a home for many years with first oil and then natural gas fired forced warm air furnace. The heat going out that flu used to drive me nuts. Only lately have I read anything about Stirling engines. It seems to me that you could use that heat using a heat exchanger as Tim mentioned to run a 12 volt generator to power the same power motor to run the blower or pump if you have baseboard heat. That way your furnace would be at least independant of outside electrical power. No one ever thought of those things years ago because all energy was dirt cheap.
December 16th, 2008 at 7:30 am
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