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Producing and using renewable energy

View enlarged Producing and using renewable energy

Using renewable, rather than fossil fuel, energy sources is important, as burning fossil fuels releases 'new' CO2 previously locked up in the earth's crust in the form of oil, gas or coal. When renewable energy like biomass is burned, the CO2 released is equivalent to that which was bound from the atmosphere during the process of photosynthesis—so, no 'new' carbon is being introduced.

The reason for the much higher percentages of renewable energy in our mills in SNA and SSA than in SEU is that, in the first two regions, a much greater proportion of our product originates from integrated pulp and paper mills. These mills typically have a higher degree of energy self-sufficiency than mills with different processes from those that only produce paper, as the black liquor (dissolved organic compounds from wood) created during the manufacture of pulp is a biofuel and primary source of renewable fuel for steam and power production.

Renewable and nuclear energy breakdown (%)
Renewable energy (%)

Comment 1 2:

Globally, there was a slight increase. In SEU, the increase was attributable to fewer standstills of the 'green power' steam turbine generator at Alfeld Mill compared to 2018. Renewable energy use at Stockstadt Mill increased due to the start-up of a new, highly efficient 'green power' steam turbine generator. The situation in SNA and SSA was stable.

1 Includes renewable and nuclear energy
2 Renewable Energy Certificates not deducted.
Energy self-sufficiency (%)

Comment:

Globally, there was a slight increase. In SEU, the increase was attributable to fewer standstills of the 'green power' steam turbine generator at Alfeld Mill compared to 2018. Renewable energy use at Stockstadt Mill increased due to the start-up of a new, highly efficient 'green power' steam turbine generator. In SNA, there was a slight increase, with both Somerset and Westbrook Mills stable and Cloquet Mill reducing both purchased and total energy. The trend in SSA was stable.

Fuel sources (%)
Energy consumption in the organisation (GJ/adt)
Energy intensity (GJ/adt)

Comment 3:

Globally, there was a slight increase in specific energy intensity. In SEU, the small increase was caused mainly by the rebuild of PM8 at Lanaken Mill. All other mills slightly increased their energy intensity because of reduced production. The integration of Condino and Carmignano Mills positively impacted specific total energy consumption. However, the integration of Rockwell Solutions, where production differs from the other mills, had a negative impact. There was a slight decrease in SNA, driven by increased DWP production at Cloquet Mill, increased pulp sales at Somerset Mill and an improvement at Westbrook Mill. SSA was stable.

3 Figures based on net calorific values.

CASE STUDY

Reducing coal and electricity consumption

As part of Stanger Mill's energy management system, in 2019, efforts were focused on coal consumption and electricity.

  • Coal: The mill endeavoured to source good quality coal and reduced coal consumption. This was supported by ongoing optimisation of boiler airflows and grate speeds, replacement of cyclones on #4 boiler, mill-wide lagging and steam trap repairs. The distributed control system upgrade on boilers also assisted in process optimisations. This resulted in a steam-to coal average of 7.1 for the year and a reduction of specific steam of 5.0 t/t in 2018 to 4.9 t/t in 2019.
  • Electricity: A new energy efficient compressor was installed and paper machine drives were upgraded to energy-efficient drives. In addition, non-essential plants were switched off during peak periods. This reduced specific electrical energy from 4.6 GJ/t in 2018 to 4.5 GJ/t in 2019.