The gas is generated by the chemistry of the stuff that was put there. Moving the stuff there takes a lot of energy, but everything sitting there mainly just needs a pump and treatment system.
This is besides the point because environmentalists (who were carped at above) tend to seek to reduce the amount of trash that needs to be shipped off to somewhere.
reducing trash is useful. Recycling of trash is sometimes worse than throwing it in a landfill. There are many different plastics and many different grades of used paper so there is no one size fits all. People often want to think I recycle so I'm good - but effort is needed to reduce packaging and things that break early.
