By George Harvey
It was not all that long ago that waste of all kinds was simply dumped into rivers. There were no laws to protect the environment, and conventional ‘wisdom’ was that the environment could absorb just about anything we wanted to throw at it, from plastic bags to plutonium.
Today, we are seeing a better way emerging. We are starting to understand the value of waste. It is not something to throw away – it is too valuable. Whether it is landfill waste, manure or human waste, food scraps, or previously unusable agricultural by-products, it is worth money. Why? The reason is that it can be converted to fuel or feedstock for a variety of things ranging from automotive fuel to plastics.
Last fall had a number of interesting news stories about waste. Each was of itself rather small, but when they are seen together, they show a trend that may eventually be highly significant.
One story is about ‘bio-methane,’ a drop-in replacement for natural gas. It has been used for some years to fuel power plants, but the news had a new twist. A company called Clean Energy is marketing bio-methane, under the trade name, “Redeem.” They have put it on sale in over thirty gas stations in California, where vehicles equipped to run on natural gas can fill up.
The process of making Redeem takes municipal or agricultural waste and turns it into a number of different things. One is bio-methane. Another is compost that can be used agriculturally. By-products exist, but they are relatively benign. The process uses agriculture waste that would otherwise decompose partly to methane, which, if uncontrolled, is far worse than the carbon dioxide released by vehicles. The carbon atoms in the process were recently in the atmosphere, and the fact that the carbon is being recycled through the atmosphere makes it possible to regard the process as carbon-neutral.
In some places, bio-methane is already being run into existing natural gas lines. As a by-product of agricultural and municipal waste, it can be less expensive. It requires some processing before it can go into the lines, however, and does require a bit of attention from the people who make it.
On the plus sides, it is a product that can be made wherever there are farms or municipal waste, and it does not require extensive, continental-scale transportation infrastructure. Other benefits are that when it is properly made, it does not contain sulfur compounds or radon, and so it can be cleaner than natural gas, entirely apart form the fact that the carbon footprint is at worst tiny, compared to natural gas with a much larger carbon load.
It is somewhat costly, but methane can be converted to such things as gasoline and diesel oil, along with such lighter fuels as butane and propane. The processes that are used to do this have been known since the 1930’s and before. So, as newer, more efficient, and less costly processes are developed and the prices of fossil fuels increase, we are also likely to see gas-to-liquid plants built making local fuel from local waste.
Right now, bio-methane is about the same price as natural gas at the gas stations that sell it, which makes it less expensive than gasoline or diesel oil. As technology for making it improves and the costs of fossil fuels continue to go up, we can doubtless expect to see more of it.