I think I was responsible for some of the Cash for Ash speculation, either in this thread or the previous one - sorry!
I think the period where the Cash for Ash scam was ongoing was a period where there was a lot of interest in green energy/fuel, including biofuel and also reducing landfill. So there would have been money available for startups that wanted to produce green(ish) energy and reduce waste going to incineration/landfill.
As pp have said, the Cash for Ash fuel was wood pellets, not something made from landfill-type waste. But at that time, the idea that you could make fuel pellets from waste was probably quite attractive and could garner seed funding etc - which seems to be what happened with Re3, which had money from a US investor.