Thanks to put that in number. I was unsatisfied with the "not good enough" conclusion after reading it, but couldn't exactly say why.

CO2 footprint probably also is better than mentioned. Certainly, it would take 4+ year to pay back for it, but what would have been the footprint for those 4+ years using coal based electricity? It's not only "how does the system perform", it's also "how does it compare".