St1 Supply

Harbours - St1 Supply

Energy audit of seaport depot

In 2016, AFRY was contracted by St1 Supply to carry out an energy audit for the company’s seaport depot in Gothenburg. With initiatives already underway, AFRY helped identify further possible savings. Since 2014, St1 in Gothenburg has reduced its energy usage by 42%, equivalent to an annual cost of 700 000 SEK.


The law on mandatory energy audits for large scale companies (2014:266) helps fulfil the demands posed by the EU energy efficiency directive EED (2012/27/EU). The law proscribes that all large companies in member countries must conduct quality assured energy audits at least every four years.

AFRY’s role

As certified energy auditors, AFRY was contracted by St1 Supply to perform an energy audit of their operations, with the aim of identifying areas of improvement and suggesting potential savings measures. The energy audit involved site visits, an inventory of significant energy users and interviews with operational staff. The AFRY project group consisted of a process engineer, an energy consultant and a certified energy auditor.

St1 had already conducted an energy audit in 2012 and started focussing on energy efficiency. Now, the newly introduced law on mandatory energy audits brought a renewed and increased energy focus. The measures implemented thus far were partially connected to changed operational products. The AFRY energy audit created an increased understanding of the function and interaction of systems, and of how energy usage might be dramatically reduced using relatively simple means.

The company believed that most major measures possible had already been taken, but further savings potential was identified.

One major change brought on by the energy audit was that the company widened its focus to include building management energy usage, as well as operational optimization of ventilation, for instance.

District heating losses proved to be considerably larger than St realised, and today some units have done away with district hearing altogether, in favour of air heater pumps.

Also, staff is helping optimize cistern temperatures, to ensure that they are not higher than necessary, while the refinery delivers temperatures that are as high as possible, keeping the heating needs of the depot to a minimum.The increased awareness and commitment of staff is noticeable thorough decreased usage of the manually controlled lighting in the tank park, and the fact that it is now only switched on when needed. These behavioural measures are a bonus, resulting from increased knowledge among employees.

The Gothenburg plant was the first of St’s depots to undergo an energy audit. In 2018, the Luleå depot was audited as well. Here, there are different challenges, due to a colder climate. Because of its great improvement in energy efficiency, the Gothenburg depot is held up as an example within St1, in the hope that other plants in the country might follow suit.


Energy usage reduced by 945 MWh/year, equivalent to 700 000 SEK/year.


Client: St1 Supply
Object: St1 Supply, Gothenburg
Project: Energy audits as per Swedish lefislation for large companies
AFRYs role: Suggesting energy efficiency improvement opportunities and energy savings measures.


Ulf Gustavsson - CDO Affärsområde Buildings Sverige

Ulf Gustavsson

CDO Business Area Buildings Sweden

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