@Hannes_SK the gas mixture what they suck off over the party headquarters of the Greens - very rarely should also occur near black holes. Energy supplier is so high, that can even keep locks in the air.
@Hannes_SK These are low calorific gases such as sewage gas or landfill gas. The gases have a relatively low specific calorific value. They are used as addon for firing cement plants or also in gypsum calcination.