Most people that do that sort of thing would have the chips/fuel as a by product of something else they are already producing. If you would have to buy the chips it wouldn't make sense. Just buy propane/natural gas to run the kiln. My old company that I worked for made wall panels for construction sites. We would build the whole apartment building in the shop and then ship the panels to the job to be erected. All of the scrap from making the panels was saved and went into a pile to be burned in the winter months to run a huge boiler system that heated multiple buildings. The scrap was a by product of the wall panel construction, so instead of throwing it out they turned it into fuel for the winter.