Alliances generate benefits for all involved – as in the case of the French heat alliance between an agricultural biogas plant and a psychiatric hospital. The 'Méthavigne' project merits a second glance, especially because society and the environment also benefit from this union of a public institution and a private company. Together with the partner Domaix Energie, the German manufacturer WELTEC BIOPOWER is setting up the heat source, a 255-kW biogas plant, in Mirecourt, Lorraine/France, a town of 6,000.
Besides the farmer and operator Nicolas Jacquot, especially the medical centre ('Centre hospitalier Ravenel') of the Département Vosges benefits from the union. Thus, the communal representatives of the clinic quickly warmed up to the pipeline construction and heat transfer project. 'With the exhaust heat from the plant, our institution will be able to cover its entire hot water needs starting from the commissioning in October 2015', says Hervé Buffe, technical manager of the hospital, expressing his approval. The suitability of the location and the short distance of only one kilometre from the biogas CHP plant convinced Buffe and his colleagues of the cooperation. Thanks to the uninterrupted procurement of green heat, the clinic can save costs and streamline its ecological profile.
When they contacted the medical centre's representatives, biogas plant operator Nicolas Jacquot and Martin Nippé, Director of Domaix Energie, were aware of the clinic's ecological orientation. Nowadays, the fulfilment of environmental requirements is a must, and the placement of public orders by the clinic is subject to strict sustainability standards. With their concept, WELTEC and Domaix Energie fulfil these standards. Accordingly, Hervé Buffe gave his OK: 'We were immediately fascinated by the idea ‒ simply everything was perfect.'
In addition to the continually reliable heat supply, the sufficient quantity generated by the biogas plant operation was decisive. The plant's heat offer is so extensive that it covers the entire hot water supply of the medical centre plus the heat needs of the home of the operator's family of five. Against this backdrop, the contract between the Jacquot family and the clinic was concluded for 10 years.
For the farmer, the business field 'energy' blends in nicely with the overall strategy. After all, the cultivated area of 375 hectares and 850 cattle allow the Jacquot family to produce all the raw materials they need for the energy generation. Starting in autumn, the 2,226-m³ stainless-steel digester will be fed with a feedstock mix of cattle manure, maize silage, crop dust, straw, grass, fruit pomace, flotation grease and food leftovers in the amount of 28 t/day.
The new 60-m³ BIG-Mix dosing feeder serves as input system. The advantage of this system is that it is able to process long-fibre substrates such as solid manure or grass in an energy-saving manner with its individually driven push strips. A vertical mixing screw then passes on the material to the second input level, the MULTIMix, mashes it with liquid manure and introduces it to the digester. After the fermentation process, a CHP plant transforms the biogas to power, which is fed into the public grid, and heat. Moreover, the digestate is stored in a 5,007-m³ stainless-steel tank and can be used on the farmer's own fields as an effective low-odour fertiliser.
These technical details were also relevant to hospital technician Hervé Buffe, as the continuous supply and economic reliability depends on these. 'This partnership between a public hospital and a private farm is probably one of the first of this type in Lorraine or even in all of France. A key aspect for us is that this concept enables us to cut our total gas consumption by 7 percent', he emphasises.