関連ワード:  is biomass a renewable energy source    biomass is a renewable energy source give reason    biomass is a renewable energy source derived from    is biomass a clean energy source    is biomass a sustainable energy source    is biomass a green energy source    is biomass a solar energy source    is biomass a non renewable energy source    is biomass/biofuels a renewable energy source    is biomass a renewable or nonrenewable energy source