It’s a phrase you may have already seen. I’m sure you were pretty confused when you heard it.
The idea is based off the old idea of “synthetic oil,” which actually began on a large scale with the Nazi’s. Yes, the German Nazi’s with an abundance of coal from the Rühr region wanted to convert it to oil for their vehicles (remember the versatility of oil compared to coal) so they could keep up with important orders of business like invading countries. Anyway, the process is quite basic, and involves coal being sprayed with a catalyst, burned in a massive furnace, and finally having a resultant gas come out at the other end. Same idea as with all fuels: the junk gets separated from the valuable stuff. Unfortunately, the process was simply too costly and made no economic sense.
The idea bounced popped up again in the 80’s when an ill-fated plant in North Dakota was operated briefly by a Yale economist and former White House official named Paul MacAvoy. The problem was selling the product, and maintaining that price through swings in oil and gas prices.
Finally, a group of Boston entrepreneurs with no relevance to the coal industry dug up some of the scientific papers from American scientists that had worked on the last round of synthetic gas plants. They were able to coerce the scientists out of retirement to get them working on a way to make the process economical.
The three Bostonians now claim they can produce natural gas from coal for a lower price than conventional drilling methods. The process even involves carbon sequestration using conventional air chilling technology, and the resulting CO2 is pumped into the ground. The methane as natural gas that results is 99.5% pure.
The process is considered clean because all of the particulate matter is removed in the making of the gas. The carbon sequestration is an extra step, but it should be included if the whole process can be done for less than the cost of the cheapest alternatives in the industry.