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Down With Oil To eliminate the petroleum source altogether, he used an epoxide derived from the oil in orange peels as a co-reactant to make plastic with CO2. Coates is working to commercialize CO2-based plastics with a range of properties, and other "environmentally benign" polymers, through a company called Novamer. Even if fossil fuel contributions were eliminated from all of these reactions, experts agree that making plastics from CO2 generated in power plants or other industrial processes will not fix the climate change problem. "When we keep burning as much fossil fuel as we are, it's going to be impossible for one chemical use to negate all of the CO2 that's made on a daily basis," Coates said. Production of all polymers worldwide amounted to about 260 million tons in 2005, according to Müller, while CO2 emissions added up to more than 100 times more. "However, if you're using CO2 instead of a petrochemical source, then you are prolonging the lifetime of the petrochemical resources that we have," said Christopher Rayner, of the University of Leeds in the U.K., who is working to make formic acid, which can be used in fuel cells, from CO2 and hydrogen. Doing As the Plants Do Another approach to providing the energy needed to turn the carbon in CO2 into a more useful form is with electrochemical cells -- which use electricity and a catalyst to convert CO2 into carbon monoxide and, eventually, into a fuel such as methanol. Daniel Dubois of the Pacific Northwest National Laboratory, another meeting presenter, is tackling this problem. "Part of the problem is, where do you get your electricity?" Rayner said of this method. Unless it comes from a renewable source, the electricity supply creates CO2 emissions that undo the gains in absorbing CO2 in the electrochemical process. There is, of course, a precedent for stripping CO2 out of the atmosphere on a large scale and converting it into all sorts of useful molecules: Plants do it all day by harnessing the sun's energy through photosynthesis and using it to build their cells and tissues. Some researchers are trying to turn CO2 back into fuels using methods similar in principle to photosynthesis -- using the energy in light to transform carbon dioxide into higher-energy molecules. Others are trying to capitalize directly on plants' ability to convert CO2 into potentially valuable molecules, including sources of fuel. It will be a challenge to identify which compounds can economically be made this way, Müller pointed out, also noting that only one percent of the sun's energy is converted by photosynthesis into plant tissue. He hopes synthetic approaches can be more efficient. "Of course we can learn from nature," he added, "We'd like to copy them." Related Links: Discovery News blog: What the Tech? |
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