Energy
In paper production at our mills we use several different types of energy sources: wood chips, peat, sludge, LPG, oil, electricity, natural gas and coal (mills in Poland and Germany). Thermal energy consumption for producing tissue paper is about 9 GJ/ton and 1.5 MWh/ton of electrical energy. These figures include energy consumption of the de-inking process.
The net consumption of energy for producing chemical pulp is almost zero as modern pulp mills produce energy as a by-product when combusting lignin in internal processes. A modern pulp mill produces more heat energy and electricity than the plant needs, and others can therefore benefit from the surplus. The wood mass not used in pulp production is combusted, and the resulting energy is recovered.
Processing recycled paper into paper pulp produces de-inking sludge. Purification of wastewater from de-inking and paper production processes also creates sludge. In the past, the sludge was deposited into landfill sites, but these days it can be combusted and the heat energy recovered. For example, at our mill in Katrinefors, 70,000 tonnes of sludge replaces some 5,500 m3 of oil. Simultaneously, the amount deposited into landfill is reduced by 90 per cent. The use of sludge as a fuel leads to considerably lower carbon dioxide emissions.