Ключевые слова: alternative energy, backgrounds, beech, biofuel, biomass, biomasse, black, briqettes, brown, bundle, close up, cylinder, energy, environment, female hand, flame, fossil fuel, group of objects, hand, handful, heap, hold, horizontal, large group of objects, match, material, nature, oac, organic, pellet, pellet gun, pellets, pine, selective focus, sunflower, woman, wood, wood chip, wood pellet, wood pellets,