Last week I attended the Energy Forum at the University of Texas at Austin. I was particularly struck by UT’s executive director of the Utility and Energy Management, Juan Ontiveros’, 10 minute energy idea talk in which he discussed the 65 MW combined heat and power (CHP) system he runs right here on campus. CHP, also known as cogeneration, is the “simultaneous production of heat and electricity from a single fuel source” . In 2009, the University received the Global District Energy Climate Award at the District Energy Summit in Copenhagen awarded by the International Energy Agency . I also found Juan Ontiveros on youtube talking about the UT’s power plant!
At the Forum Friday, Ontiveros also discussed the energy policy in Denmark that makes it mandatory for any new power plants constructed to be combined heat and power. In Denmark, power stations exclusively producing electricity utilize only 62% of the energy fuel has to offer while CHP utilizes 90% without releasing more CO2 . 62% of household in Denmark have such district heating . One of Denmark’s energy goals is to be completely free from fossil fuels by 2020 and the combined higher efficiency obtained by CHP as well as a switch to renewable energy is a means of achieving this .
The two most common CHPs are gas turbine or engine with heat recovery unit and steam boiler with steam turbine. Below are two schematics illustrating how these two types of CHPs work.
Gas Turbine or Engine with Heat Recovery Unit 
Steam Boiler with Steam Turbine 
The benefits of CHP are endless! They include efficiency benefits, reliability benefits, environmental benefits and economic benefits. CHP are more efficient since they use less fuel to produce each unit of energy and since on-site generation avoids losses from distribution since energy is lost when it travels long distances on transmission lines, it’s reliable since it is generated on-site and is not affected by the power grid, it’s environmentally beneficial since less fuel means less emissions of greenhouse gases, and economically beneficial because of its high efficiency and independence of fluctuating prices for energy received from the grid .
In the US, Con Edison operates the largest district steam system “providing steam for heating, hot water, and air conditioning to approximately 1,800 customers in Manhattan” . This is one example of an estimated 5,800 district heating and cooling systems throughout the US which provide an estimated 320 million MWh of thermal energy, providing only 5% of the nations heating and cooling load . In comparison with Denmark’s policy, I’m curious as to why the United States does not push for a similar increase in power plants that utilize combined heat and power. To me, UT’s example could be followed at universities and save a significant amount of energy. Similarly, communities and cities could utilize this energy saving technique. I’d love to hear if you have any ideas why such a widespread use of CHP, like in Denmark, isn’t adopted here; or perhaps there are obstacles that make it more difficult?