Low-priced feedstock, such as solid manure, grass and silage, is used to feed biogas plants equipped with robust technology. The naturally high fibre content in these substrates places great demands on both the technology and the biology. The raw fibres in the substrate are extremely difficult to “digest” for the bacteria in the digester. Our Heatcrack heat technology breaks down the unprocessed raw fibre contents in a thermal process so that they can be processed more easily by the bacteria. The heat technology tests conducted by our research laboratory have yielded excellent results: In practice, the biogas yield is increased by up to 5 % by using the substrate break-down system.