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Green gas production

Processing the sugar beets generates waste flows in the form of beet tips and residual foliage. In the past, these waste flows were transported to a composting company. However, the energetic value of these plant residues can be put to better use by digesting them at the site. The digester produces biogas and all the valuable minerals are left behind in the digestate. The digestate is used in agriculture as a fertiliser, so the minerals are recycled in a closed loop system. This helps keep the soil healthy and is an excellent example of how recycling loops can be closed locally in a circular process.
Each digester processes more than 100,000 tonnes of plant waste each year. These plant-based raw materials largely originate from the factory's in-house process, but may also include waste flows from other companies in the food sector such as potato peelings, Cigarant or cutting waste generated when processing vegetables. 


The biogas produced in the digestion process contains less methane than natural gas and has to be upgraded first before it can be pumped into the public gas grid. This is also part of Suiker Unie's green gas production activity. The green gas is sold to BioMCN.
When all the systems are running at full capacity, Suiker Unie delivers roughly 30 million cubic metres of green gas to the gas grid each year. This makes Suiker Unie one of the largest producers of sustainable gas in the Netherlands.
Suiker Unie also sees opportunities for achieving greater efficiency by digesting rather than drying the excess pressed pulp. Drying this pressed pulp requires a great deal of energy. Digesting it, on the other hand, generates energy. View the video below for more information: