Landfill fuel gas production.

burying a huge amount of trash and loose organics like potato's then putting a natural gas extractor on top will slowly convert it into contaminated dirt and fuel gas. You can then use the fuel gas and clean the contaminated dirt in some way later.

Real landfills have flare towers from how much methane they make. It would be cool to show off in game. It's a fuel source that is being wasted in the real world right now and it would be cool to show a practical use for it in game.