[maCDzP]

This made me chuckle. I am guessing he is trying to show how ridiculous our life style is without fossil fuels?

[rambambram]

Definitely. This is an art project (ArteZ is an art school in The Netherlands) and the naming suggests a lot of fun! - Slootmotor: already explained in article - Uitsloot: pun on exhaust gas and ditch - Plompstation: pun on gas station and pond/water

[Cthulhu_]

Looks more like a proof of concept that you can get enough methane to run a moped from your local ponds.

[the_rectifier]

Not at all. Did you read the article?