Garbage in Power Out

One of the more interesting technologies to emerge from the last few decades of interest in alternative energy is plasma gasification, or more properly plasma arc gasification. The plasma is produced from an arc of electricity. You can think of it as a controlled and continuous bolt of lightning. It was originally developed by NASA as a means of simulating reentry temperatures for spacecraft. The Army adopted it in the early nineties as a way of destroying hazardous chemicals, especially old chemical munitions. It works because it produces temperatures hotter than the surface of the sun. Any substance on earth exposed to that kind of heat is reduced to its elemental atomic components. The technology can be used to dispose of all sorts of toxic chemicals. It isn’t much help with nuclear waste because radioactive materials are already in elemental form but for things like PCBs it is just the trick.

The plot thickens when we begin to think about what other materials we can break down, and what we can use the byproducts for. As for the latter, extremely hot gasses can be used to drive turbines and produce electricity. Depending on the gasses they may also be used to produce hydrocarbons. Resulting gasoline, diesel, and jet fuels can be readily cleansed of most of the pollutants we usually associate with them. Inorganic residue can be used to produce industrial chemicals or even construction materials. As for what feed stocks might be used, the most obvious choice is municipal waste. You might think the immense heat required would demand more energy than the process would produce but that turns out not to be the case. Once the process begins it produces more than enough energy to sustain itself. The excess has the potential to provide as much as 5% of our electricity needs from the nation’s garbage alone. It could eliminate the need for landfills and there are no smokestacks. The input materials aren’t burned. They are turned into gas in a closed system. There need be no release to the outside air.

The technology seems to be picking up steam. A company called InEnTec demonstrated a system at Port Arthur in June that produces ultra clean synthesis gas from chemical residuals normally treated as hazardous waste and incinerated. InEnTec is planning a commercial facility to produce hydrogen. Dow Chemical has adopted the technology for a plant in Michigan. St. Lucie County in Florida is building a garbage processing plant to replace its landfill and produce 60 MW of electricity at a cost competitive with natural gas. Environmentalists tend not to like it because they say it hasn’t been proven in the US but if these projects turn out to be as clean and economically sound as their backers expect we should see a wave of new construction over the next few years. It has some pretty significant advantages. It doesn’t have the long lead times or waste issues nuclear power has. And the knock on coal gasification is it burns coal to create the temperatures to produce the gas, and generates lots of extra carbon dioxide in the process. The plasma arc doesn’t burn anything. And a solution to the land fill problem should be attractive to every municipality in the country. No more methane emissions, no ground water contamination, no worries about non-biodegradable trash, a built in substitute for expensive re-cycling programs, and no more smelly eyesores in the landscape. What’s not to like?

Of course we’ve heard these promises before and not just from clean coal. This may not work out either for one reason or another. Environmentalists are right that it hasn’t been proved commercially. But sooner or later one of these ideas is bound to work.