Ahlstrom-Munksjo is a global company within the paper industry. Their mill in Billingsfors was in need of an energy audit, localizing energy ows within the mill. An energy audit is a good tool for any company to get a good overview picture of their energy usage of the examined system, it is also seen as the rst stage for an energy-saving strategy. On the Billingsfors mill, the energy audit is included in the continuous work of increasing their energy eciency in order to keep up with the new regulations and advancements in this industry sector.

The energy audit was done on the whole mill with focus on the paper production and the district heating system. More detailed information about the paper production, a comparative study of two paper machines, PM2 and PM6, is also presented. The reason for the comparative study on PM2 and PM6 was due to an unexpectedly high recorded gas consumption from PM2. The two paper machines were believed to be similar enough to compare them without any deeper knowledge of the machines. They were also compared to a reference machine, representing an average machine with similar setup. The comparisons showed that PM2 does in fact have a higher gas consumption than PM6. To identify the reason for the higher consumption the dry solid contents of PM2 needs to be examined. The two machines do not have the exact same process when producing paper and a more detailed comparative study should be done for a better understanding of the high gas consumption.

However, the two machines have a lower gas consumption than the reference machine, this meaning they both have a relatively low gas consumption.