wood pellets for heating industrial boiler houses with bio fuel in fire. modern energy concept. biomass wood pellets pile. eco-

pellet wood biomass woodpile environment fuel energy pile material stack alternative eco heap nature natural power renewable bio ecology compressed firewood background biofuel heat recycling timber industry log wooden solid organic biological ecological economy mass oak sustainable surface green technology snack domestic waste biodegradable pellets heating industrial boiler houses fire modern concept ecofriendly low cost