Cardinal Cogeneration makes coal obsolete
Sure, we don't use coal anymore -- but how much better is natural gas?
Monday, October 26, 2009 - 14:37
THE SUN SETS ON STANFORD COAL: A view of the main quad at dusk. (Photo: Jill Clardy/Flickr)
Stanford hasn't used coal for a long, long time. Ever the site for innovation, the school has relied on the Cardinal Cogeneration Plant as its main source of energy since the late 1980s, a key component of Stanford's Central Energy Facility (CEF). But what exactly is cogeneration, and how much better is it actually than coal?
To start with, the Cardinal Cogeneration Plant is one of four CEF components: The Boiler Plant, the Chilled Water Plant, the Cogeneration Plant and the Ice Plant. If this sounds to you like an energy-slanted take on the Fantastic Four, you wouldn't be too far off.
Standing strong as back-up for the Cogeneration Plant is the Boiler Plant, which operates on natural gas and provides supplemental energy resources for peak heating demand. Next, the Chilled Water Plant is what makes the Cogeneration Plant in part so much more sustainable than an ordinary coal-fired one--it captures the excess steam from the cogen plant during the summer when steam loads are low and electricity rates are high, and then provides the steam back to the cogen plant in off-peak and winter months. As for the Ice Plant, it simply provides additional cooling during the summer without having to operate electric chillers when electricity is at peak demand.
Then we have our superhero: The Cardinal Cogeneration Plant. Commissioned in 1987, the plant is a combined cycle power plant that consists of a natural gas powered turbine that powers a 42 MW generator, a waste heat recovery steam generator and a steam power turbine that powers a 14 MW generator. Stanford uses about 60 percent of the electrical power from this plant (the rest is sold back to GE) and then 80 percent of the excess waste heat for the campus's heating needs.
Yet at a sustainability meeting last spring, Stanford sustainability representative Fahmida Ahmed voiced the current concern with cogen: "The fuel being used is still natural gas."
Stanford has indeed come a long way from coal, but now the next step is to come a long way from cogen. The school's energy surveyors recently discovered that the heating demands of the university could already be met by the heat that the campus cooling system removes from the buildings. The reconfiguration project would move the campus from a policy of "cogeneration" to one of "regeneration" -- costing somewhere around $250 million. Yet the high price tag will hopefully be offset by the energy savings the campus will enjoy over the long term.
If you're interested in learning more about Stanford's next steps, check out the recent article about the new plan in Dan Stober's Stanford University News article. And stay tuned for more Stanford energy developments: After we go beyond cogen, who knows what will happen next?
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