První energeticky soběstačná obec Kněžice
ve výrobě tepla a elektřiny v ČR
The first energy-independent municipality of Kněžice
in the production of heat and electricity in the Czech Republic. In the sense of the technical and technological today, it requires dusting off the essence of the farmer’s way of thinking, reviving the historical image of the countryside, where our grandfathers and gre
at-grandfathers easily gathered energy resources from their surroundings on a daily basis by means of a long established, sophisticated annual cycle of nature-friendly activities associated with plant cultivation, animal nutrition, and processing of natural compostable waste. In the first half of the 20th century, country people still had the energy sources they needed where they lived and worked. They had fodder for animals, good food for themselves, wood for the stove, and returned ash back into the wild. Horses and cattle provided them with cheap and easy to replace draft power, independent of oil or natural gas. This, in general, led to the self-sufficiency of the region and the country. Modern times are, of course, different, but in terms of energy, food, and nature it is the same. We all want to have a warm home, good food, beautiful, unspoilt nature, and in addition, we want it all to match the current trend of sustainable development. This is what was going on in the minds of the inhabitants of a small Czech town on the Elbe River, Kněžice u Městce Králové, at the season of the traditional autumn and winter smoke exhausts rising from people’s heaving brown-coal-fuelled boilers, piles of rotting branches and cut grass lying at the town squares, and the household septic tanks overflowing into the drains of surface water. In the end, the feeling of dissatisfaction led to a solution that started with a statement: “we are historical farmers, and hardly anything could ever change that. We can work with what our activities by-produce as biodegradable waste, which, when freely decaying in nature, brings a significant biochemical burden on our town and nature as a whole. On the other hand, it is all underestimated energy material. Let’s define an area in which we can use efficient technology to effectively help the laws of nature, benefiting thus both nature and ourselves." This is the story behind the project of an energy-self-sufficient town, where the majority of waste material is transformed into biogas and, combined with direct combustion of phytomass, forms a closed circle of energy that generates electricity for sale to the public and heat energy for local consumption of the town inhabitants. The energy-free residue from biogas production and ash from the boiler house are returned to the field as a fertilizer. We chose to build a biogas plant because it was a solution to several problems. Firstly, it replaces a wastewater treatment plant and a sewer system. Kněžice has five hundred inhabitants, of whom a hundred live away, in two local sections, and we could not have built sewers for them. Acquiring the necessary technology, we realized we could collect waste from Kněžice as well and utilise it at a biogas plant. This was crucial in the financial plan of the entire project. Although the investment cost of the project was enormous, cutting the cost of a sewerage system and wastewater plant means saving roughly 45 million. The next step for us was to decide to follow the same method also when disposing of all biological waste, i.e. grass from town greens, of which there are about 10 acres, which is quite a lot, raked leaves, waste from households, canteens, etc. I would definitely recommend this system to other towns; nevertheless I would encourage them to come see our or similar facility and learn from the mistakes that we have made, through no fault of our own but only because the system was new to us. There are various combinations that can be modelled based on the capabilities of other municipalities. Our project has had a pivotal influence on the air in our town, which one can tell just walking around. Prior to the project, when there was inversion, there would be clouds of smoke rolling on the ground in the early morning, while now the problem is solved thanks to the ESO system. We are now planning to expand the system with dry fermentation in order to use biodegradable wastes containing sand, stones, and other particles that find no use in the existing wet part. This is a brief description of our project, which could go on for pages, including also comparison of the pros and cons of building the system. Milan Kazda
mayor Knezice municipality
