Cogeneration: This Ain't Your Daddy's Energy Plan
by William McIvor '12Science & Technology Writer
"Going Green" is a popular trend both here at Hamilton and in the world at large. On Tuesday, President Obama pledged to the United Nations to take "ambitious actions" in fighting global warming and reiterated his pledge to cut U.S. emissions to below 1990 levels by 2020, a 14 percent decrease.
In trying to do our part in saving the environment up on the Hill, we have had solar panels and a wind turbine installed, we use some geothermal heating, and we organize sexually suggestive campaigns to save energy. The recently concluded "Do it in the Dark" dorm competition successfully reduced dorm energy use this past month by 17 percent, a laudable achievement to be sure, and will certainly help Obama keep his 14 percent pledge. But did you know that there is technology available today with which we could reduce nationwide energy use by almost 30 percent and greenhouse gas emissions by almost 50 percent in a similar time frame? It's called cogeneration, and is considered one of the most promising solutions to the current energy crisis.
The energy production and distribution network we have right now is horribly inefficient. Power plants operate at 30-35 percent efficiency, meaning up to 70 percent of the energy they produce is wasted. This is because turning heat energy produced from coal, for example, into rotational energy to produce electricity wastes much of the heat, and long distance transmission of electricity through wires also saps efficiency. Cogeneration, otherwise known as Combined Heating and Power (CHP), is simply the process of generating electricity and also capturing the heat energy that is usually wasted in this process to make hot water or steam to use for heating, vastly increasing efficiency.
Producing both electricity and heating from the same source is much more efficient than the energy production system we have now, but there are some problems in large-scale implementation. Although some countries, such as the Netherlands, have large centralized cogeneration plants, it is hard and inefficient to distribute the heat energy, and efficiency is lost in the transmission of electricity as well. On a smaller scale, several universities, including New York University, are considering using cogeneration to produce their heat and electricity and Massachusetts Institute of Technology has implemented a 10-year, 40 million dollar initiative to do just that. The largest potential for cogeneration, however, is in micro cogeneration, where small, highly efficient units produce both electricity and heat for individual buildings or complexes. If used with something called an absorption chiller, the heat energy can even be used to produce cold water for air conditioning in the summer.
There are several units on the market already that do this. Most run off of natural gas and operate at 85-98 percent efficiency, a huge increase over current energy efficiency. If almost all of the U.S. energy needs were produced on site using cogeneration operating at only 85 percent efficiency, total energy use would decrease 16 percent and total energy waste would decrease by almost 40 percent. This would allow every coal and nuclear power plant to be shut down. Use of natural gas, which can be produced domestically, would have to increase 63 percent, but would still lead to a 27 percent emissions decrease, or 1,520 million tons of carbon dioxide per year.
After electricity production, the biggest source of energy waste is transportation, which operates at an average of 20 percent energy efficiency. If all-electric vehicles were used, however, and were charged with electricity produced by cogeneration, total energy consumption would decrease 27 percent, total energy waste would decrease by 60 percent, coal and nuclear plants could be shut down, and oil use would be cut by 51 percent. Natural gas use would increase 104 percent, but would still lead to a 45 percent decrease in emissions, or 2,500 million tons of carbon dioxide per year.
The technology necessary to make these changes is available; many well known companies such as Honda and Synertech make micro-cogeneration units and they can easily be installed in place of a hot water heater without the need to retrofit anything in most houses. While they are currently more expensive than a traditional water heater, ranging from $6,000 to $20,000, they will pay for themselves in fewer than ten years in energy savings. The only major barriers to these units being widespread in the market is the lack of knowledge about them and the absence of companies that will actually deliver and install units, but if more people come to realize the potential that cogeneration has, companies will spring up to fill the gap.
At the moment, cogeneration is still based on fossil fuels, namely natural gas, but potential future systems to generate electricity such as fuel cells, nuclear, and solar-thermal still produce waste heat, and cogeneration could be used to make these systems more efficient as well. Given cogeneration's enormous potential not only to quickly and drastically reduce emissions and energy use but also to bolster the future of energy production, it is a technology that needs to see widespread use.
If the government put its weight behind the widespread use of cogeneration, it would be possible to put a unit in every home in 10 to 15 years. Mass production would make units even cheaper and more cost effective, and there is nothing else that needs to be done with this technology except start using it. Given this, next time Hamilton considers a new energy efficient investment, cogeneration should be considered instead of solar panels and wind turbines.