To take advantage of the tax credit the EFM coal boilers were tested with a few biomass products and are now being designated multi fuel boilers. If you're unfamiliar with the EFM stokers they are in quite a unique position to provide this. The EFM rep has mentioned to me in the past that a lot of farmers were already running a 50/50 mix of anthracite and corn. The reason it's possible with this particular boiler is it uses an underfed pot supplied by an auger. Most coal boilers and stokers use a bed design which is unsuitable for biomass. I should note these are full boilers installed in basement designed to heat a whole house, not sure what the current state is in the biomass area but these units are built like the proverbial brick chit house. EFM has been in the business since the 20's and this particular design hasn't changed much in 50 years.