At the moment hog fuel is burned. Not everyone is equally technically aware and forward thinking.
But the concept of bio-digestion to create a cleaner fuel is definitely in the works in some places.
When you build a multi million dollar installation with a ROI of thirty years you don't just scrap it because ten years laker something better comes along. You use the new technology on the next project. You look at whether it is feasible and economic to do a conversion.
and above al else, you try hard not to throw out the baby with the bath water.