wood briquettes (ruf type), made of beech and oak burning inside the wood fuel boiler. alternative fuel

alternative fuel background bio bioenergy biomass block boiler brick briquette briquettes briquetting burn chip compressed dry eco ecology energy generation sources fire place fireplace firewood flame flames hardwood heap heat industry natural nature oven power renewable resource ruf type sawdust solid solidfuel stack sustained texture wood wooden beech oak burning inside boiler