Canada

Garbage dumps are close to the grid and the users.

Many of the worst offenders are very old wells, as much as a century old. Their original owners are long gone which is how governments ended up being burdened with capping them.

Like many old toxic mines, the creators of the problems have evaded legal liability by going out of business. Legal frameworks may be more rigorous now but the old wells and mines remain.

Some of the oldest wells, like the ones near Petrolia in SW Ontario, might be economically viable for methane power generation. Others in Saskatchewan and Alberta are likely not.