Hydrothermal carbonization

Technically, the process imitates, within a few hours, the brown coal formation process (German "Inkohlung", literally "coalification"), which takes place in nature over enormously longer geological periods of 50,000 to 50 million years. It was investigated by Friedrich Bergius and first described in 1913. The carbon efficiency of most processes for converting organic matter into fuel is relatively low, i.e., the proportion of carbon contained in the biomass, which is later contained in the usable end product, is relatively low: In poorly designed systems, the unused carbon escapes into the atmosphere as carbon dioxide, or, when fermented, as methane. Both gases are greenhouse gases with methane even more climate-active on a per molecule basis than CO2. In addition, the heat that is released in these processes is not generally used. Advanced modern systems capture nearly all the gases and use the heat as part of the process or for district heating. The problem with the production of biodiesel from oil plants is that only the energy contained in the fruit can be used. If the entire plant could be used for fuel production, the energy yield could be increased by a factor of three to five with the same cultivation area when growing fast-growing plants such as willow, poplar, miscanthus, hemp, reeds or forestry, while simultaneously reducing energy, fertilizer and herbicide use, with the possibility of using – for current energy plant cultivation – poor soil.