Thursday, 16 September 2021
Leading European packaging company, DS Smith, is looking to invest EUR 7.5 million in expanding its anaerobic digestion (AD) facilities at its paper mill in northern France.
The investment will enable the site to process 100 per cent of its wastewater into biogas. The biogas is used to produce electricity, which is fed into the French national electricity grid (RTE).
This will boost the production of biogas from 26 000 MWh to 39 000 MWh, an increase of 50% which DS Smith claims could result in additional savings of 2 600 CO2 per year, equivalent to annual emissions of about 600 small cars.
The treatment of waste is also a big boon to the Rouen operations - in particular, the AD process results in a reduction in sludge which normally must be removed via vehicles. This development is in line with the company's sustainability strategy of taking 250 000 lorries off the road.
DS Smith has committed to a 40% reduction in CO2 emissions per tonne of product by 2030, using recent 2019 levels as a benchmark, on the road to net zero in 2050.
Bruno Šteh, Cluster Energy Coordinator for DS Smith said:
"We are very proud to have increased our green energy credentials with the expansion of our wastewater treatment facilities at Rouen Paper Mill. We are not only treating the wastewater onsite but extracting a naturally produced resource that is converted into green electricity. This investment was a key driver in our overall strategy to reduce the impact of our operations here in France and contribute to providing green power to the region."
Note that biomethane is not produced at the Rouen facility - rather than upgrading the biogas, it is utilised directly in a cogeneration plant. The plant is operated by Idex, combusting biogas to produce electricity and steam, with the steam being used on site.
For industries that require process steam for their operation and produce biogas, cogeneration will likely be the preferred option to biomethane. Furthermore, the transport of biomethane will likely require a gas grid connection which will not always be available or viable. For 2019, the EBA reported that of the 6 TWh biogas produced in France, 2.3 TWh of electricity was produced compared to 2.2 TWh of biomethane via the upgrading of biogas.
In general, the pulp and paper industry focuses upon energy recovery from waste streams, addressing energy supply, carbon emissions and waste treatment simultaneously. In particular, the use of boilers for recovering energy from spent liquor resulting from the Kraft pulp process is a common practice. However, processing of wastewater using AD to produce biogas, as occurs in Rouen, is also applicable to many pulp and paper sites.
DS Smith has made significant strides in reducing emissions overall, reporting a 50% drop in emissions intensity from 308 kg CO2 per tonne of product in 2011 to 212 kg CO2 per tonne of product in 2020.