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Public Radio's Environmental News Magazine (follow us on Google News)

Energy Co-generation

Air Date: Week of

For capturing waste heat to generate cheap and clean energy, one of the most promising technologies is called 'combined heat and power.' Proponents say it can triple the efficiency of power plants, and reduce carbon dioxide emissions.. Living On Earth's Daniel Grossman prepared this report.


KNOY: It's Living on Earth. I'm Laura Knoy.
Late last year representatives of the world's industrialized nations agreed to curb climate change by reducing the amount of carbon dioxide they release into the atmosphere. The Kyoto Accord didn't prescribe how to make the cuts, but energy experts agree it will mean burning less fossil fuel and squeezing the most energy out of carbon-based fuels that are used. One of the most promising technologies is called combined heat and power. Proponents say it can triple the efficiency of power plants and reduce carbon dioxide emissions. Daniel Grossman prepared our report.

GROSSMAN: The Kyoto summit over, attention is shifting from the diplomacy of reaching agreement to the nuts and bolts of compliance. In a recent speech, President Clinton acknowledged that curbing climate change will not be easy. But he said it can be done without economic hardship. Cutting carbon dioxide is the most important part. In the United States, the gas comes in almost equal parts from cars and trucks, buildings and factories, and power plants. In his speech, the President singled out power production for special attention.

CLINTON: Today, two-thirds of the energy used to provide electricity is squandered in waste heat. We can do much, much better.

GROSSMAN: And the White House itself may soon showcase how.

(Trumpets play. Woman's voice-over: "In a short while you will be entering the White House. This is a unique privilege...")

GROSSMAN: The building is heated by steam produced a few blocks away at Washington's Central Heating and Refrigeration Plant.

CASTEN: That power plant heats about 110 Federal Government buildings, including 1600 Pennsylvania, which is where the President lives.

GROSSMAN: Thomas Casten heads Trigen Energy. He says the plant is unnecessary.

CASTEN: If we go south about 2 miles, along the Potomac River, there's a plant that's owned by Potomac Electric Company, which makes 400 megawatts of electricity and puts 800 megawatts of heat into the Potomac River. There's more than enough heat going into the river to heat every major building in Washington, DC.

GROSSMAN: With prodding from the President, Mr. Casten and Potomac Electric executives are making plans to sell the utility's waste heat and shut down the old heating plant. The idea of making steam heat and electricity in the same place, called combined heat and power, is not new. Some factories, like energy-intensive paper mills, have been using this fuel-saving trick for decades. After the oil embargo of 1973, Federal officials tried to promote it without much luck. Today, just as the need to cut back on carbon dioxide emitted using fossil fuels has become more urgent, technological improvements have made combined heat and power more efficient, more economical, and easier to install. Energy experts say the technology could play a much larger role wherever centralized steam systems exist, including thousands of universities and hospital complexes and about 100 US cities. But they say it makes economic sense for anyone owning a building bigger than a medium- sized high-rise. And Joseph Romm, the Energy Department's top official for energy efficiency, says the Potomac electric project could give the concept the PR boost it needs.

ROMM: This is a huge opportunity in the Capitol to show that it is possible to really transform the energy system of this country and actually lower pollution and lower people's energy bills at the same time.

GROSSMAN: More than one dozen cities including New York, Chicago, and Seattle, already get steam heat from power plants. Some get chilled water for air conditioning as well. Philadelphia is the latest city to join the club, with the plant recently renovated by Trigen Energy, one of many companies fostering this technology.

(Motors and fans, loud high-pitched sounds)

SMTTH: Now this will be real noisy up here; I'll show you what the gas engine does...

GROSSMAN: Plant manager Steven Smith shepherds me on a tour of the sprawling brick and steel complex. In one room fuel is burned in a shrieking blast of fiery gas. Steps away the inferno's flames turn water to scalding steam. Following the path of the plant's labyrinthine plumbing, Mr. Smith opens a fire door and climbs onto a steel catwalk beneath a vaulting ceiling. The throbbing heart of the complex, nestled amidst silver steam arteries.

SMITH: Yeah, what we started out coming into this room is steam at a very high temperature and a very high pressure. The steam is put through then...

GROSSMAN: The steam powers a turbine which turns a generator to make electricity. Turbines like this one need hot, high-pressure steam. Steam passing out of the turbine is still hot, but it's too spent to make more electricity. Usually such heat is dumped in cooling towers or waterways. It's hard to believe, but most US electric plants convert only one third of their fuel energy into electricity. The rest is wasted. But not here.

SMITH: And that steam, after being used to produce electricity, is then leaving the plant going through 33 miles of pipelines, which is heating some 200,000 people in their offices and homes and facilities in central Philadelphia.

GROSSMAN: This facility has made steam for decades, just like the central heating building in the Capitol, along with a tiny amount of electricity. Now, because it generates heat and power in roughly equal proportions and does so with natural gas instead of oil, the plant is among the most efficient in the nation. Trigen President Thomas Casten.

KASTEN: That plant will put out 6% of the pollutants of the plants that it replaces. And it will cut the carbon dioxide output roughly in half. The plant is more than twice as efficient as the US average.

GROSSMAN: Energy experts say equipment soon available will be 3 times as efficient as today's average. In Europe, greater population density and the tradition that both steam heat and electricity are supplied by a single utility have made combined heat and power, or CHP, common. David Green, who heads Britain's Combined Heat And Power Trade Association, says Denmark leads the pack.

GREEN: The whole of Copenhagen is heated by one very large heating infrastructure, with the heat coming from several power plants located around the city. It's become a very energy-efficient city. In the UK, we've had a lot of small-scale CHP schemes, and we have Buckingham Palace, for example, is powered by CHP, and we have 2 CHP units in the House of Commons. And Windsor Castle has just been converted to CHP as well.

GROSSMAN: Ten percent of European electricity comes from plants that reuse excess heat. In the US, only 6% does. Energy analysts say the reasons include rigid air pollution rules that don't take into account that plants like the one in Philadelphia are doing 2 jobs in 1 building. And tax rules that discourage investment in combined heat and power. The Energy Department's Joseph Romm says the most important roadblock is a regulatory system that guarantees profits to electric utility monopolies.

ROMM: Existing utilities have had no incentive whatsoever to become more efficient because the way you add to your rate base is to get a new power plant built. So you don't want to make your existing power plants more efficient.

GROSSMAN: But change is coming. Six states, including California, Pennsylvania, and Massachusetts, have just adopted laws to open power markets to competition. Restructuring of the electricity industry could encourage investors to build more efficient power plants, says Joseph Romm. He predicts that in the next decade or so, electricity generated by combined heat and power plants will double. If he's right, the technology could help the US make 7% of the greenhouse gas cuts it needs to meet its obligations under the Kyoto Agreement. All of which supports President Clinton's claim that the US can protect the climate and the standard of living. For Living on Earth, I'm Daniel Grossman.



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