The plant in Missouri seems to belie your skepticism. I would never bet my life savings on a single company, but I would invest some money in this one if it were publicly traded. My concerns are more in the realms of cost-effectiveness and zoning type issues -- can these plants recover the costs of building and maintaining them? Does the process produce inordinate noise or odor (a detriment to building them in lieu of landfills)? From the technical side, how "known" does the input mix need to be to be efficient?
As the operators gain experience they plants could be built to handle more variable streams such as municipal or industrial waste.
There's still a whole lot of engineering that needs to be done. Think of it as automobiles in the 1930's or semiconductors in the 1960's...
Not so, Just proves that there were enough investors roped in to finance the plant. The trial of my scepticism will come if the plant actually makes a net profit.
There were studies done in the '70s by IEEE on internal combustion powered small generators off the methane produced by landfills - same concept. Their conclusion was that it wasn't cost effective.