Ключевые слова: alternative energy, backgrounds, beech, biofuel, biomass, biomasse, black, briqettes, brown, bundle, closeup, cylinder, energy, environment, female hand, fire, flame, flames, fossil fuel, fuel and power, group of objects, hand, handful, heap, hold, horizontal, large group of objects, log, material, nature, oak, organic, pellet, pellet gun, pellets, pine, selective focus, smoke, trunk, woman, wood, wood chip, wood pellet, wood pellets,