Maybe on to something here......

 Methane gas is produced by rotting vegetation/peat etc. and can be found in ponds, ditches, lakes, marshes and other still bodies of water.

This young bloke from Arnhem has a novel method to recover and collect the gas to run his moped.

He stomps around and stirs up the muck on the bottom to release the methane gas bubbles, collects it then pumps it into a bladder on his moped.

He has a website.

Now, if we could just capture all those farts....

.....and a YouTube video.

Here's the link.

https://youtu.be/KyoeO9UFZwQ 

Titbits :-

Methane gas plants using animal manure cow/pigs/chickens are not popular in Netherlands.

A group of dairy and pig farmers tried for years to build a gas plant near us, in Varsseveld, had broken ground, but we're shut down by the Greens, environmentalists and other NIMBY protestors.

Lack of financing finally killed the project.

Here is a home biogas methane kit.