As more vessels become electrified and the EU requires ports to provide onshore power supply, pressure is mounting on Swedish ports to invest in new infrastructure. The question, however, is how much electricity each port will actually need. A new pre-study from Lighthouse and the Swedish Transport Administration shows that system scalability is crucial, and that systems must be able to grow in line with the electrification of shipping without becoming obsolete after just a few years.

“Many medium-sized ports need to invest in onshore power supply infrastructure today, while future electricity demand remains uncertain. The aim of the study was to help ports make better-informed, longer-term investment decisions,” says Nicole Costa of RISE, coordinator of the pre-study Scalable Onshore Power Supply Systems for Mid-Sized Ports, which was carried out within the Swedish Transport Administration’s industry programme Sustainable Shipping, managed by Lighthouse.

Onshore Power Supply (OPS) enables vessels to switch off their auxiliary engines while berthed and connect directly to the port’s electrical grid. This results in lower emissions, reduced noise levels, and decreased fuel consumption. Under the EU’s Alternative Fuels Infrastructure Regulation (AFIR), an increasing number of ports will be required to offer onshore power supply in the coming years.

The challenge is that there is still uncertainty regarding how much power future vessels will require and which vessels will call at specific berths over the longer term. While some vessels will mainly use shore power to operate onboard electrical systems, others may need to recharge large battery packs within a short period of time.

To address this, the researchers analysed three future scenarios: one involving smaller or partially electrified vessels, one involving hybrid vessels with greater charging needs, and one involving fully electric vessels requiring very high power levels.

“We wanted to understand how onshore power supply systems can be designed to expand over time, rather than becoming either too small or unnecessarily oversized,” says Nicole Costa.

According to the pre-study, scalability must be considered from the very beginning.

“Many of the most critical decisions are made early in a project. These decisions determine whether a system can be expanded cost-effectively in the future,” says Nicole Costa.

The report therefore recommends modular solutions, allowing new components to be added gradually as demand increases.

Another key finding is that battery energy storage systems could play a central role in future ports. Batteries can be charged continuously and then used when vessels connect to the onshore power system. This helps reduce peak loads and ease the strain on the electricity grid. According to the report’s calculations, battery storage systems could reduce daily operating costs by five to seven percent in some cases.

“Batteries can help shave power peaks, reduce pressure on local electricity grids, and lower operating costs. At the same time, they are not necessary in every port and should be evaluated based on local conditions,” says Nicole Costa.

The study also highlights the importance of international standards. If vessels are to connect to shore power in different ports, common technical solutions are needed for voltage, frequency, safety, and communication systems. Without standardisation, investments risk becoming more expensive and more complex.

“Our recommendation is that ports should not only focus on today’s electricity demand, but also consider how requirements may evolve over the next 10 to 20 years. By designing shore power systems to be scalable from the outset, ports can reduce costs and investment risks, avoid expensive upgrades later on, and be better prepared for the rapid electrification of shipping.”

The report Scalable Onshore Power Supply Systems for Mid-Sized Ports was authored by:
Matilda Arvidsson, Henrik Hemark, Mikael Johansson (DNV)
Qian Xun, Nicole Costa, Vendela Santén (RISE)
In collaboration with:
Stena (Sebastian Packalén, Hans Tistrand)
Port of Gothenburg (Besha Welander)
ABB (Jörgen Karlsson, Chris Poyner)
Actemium (André Olofsson)