Global shipping is responsible for around 3% of greenhouse gas (GHG) emissions. Just last month, in April 2025, the International Maritime Organization (IMO) approved a landmark Net-Zero Framework, aiming for net-zero GHG emissions from global shipping by or around 2050. Although the pace of maritime decarbonization needs to be accelerated, this framework introduces mandatory emissions limits and a global carbon pricing mechanism, marking the first such comprehensive approach in the maritime sector. Additionally, the FuelEU Maritime regulation, effective from January 2025, mandates gradual reductions in the GHG intensity of fuels used by ships, starting with a 2% reduction in 2025 and aiming for up to an 80% reduction by 2050. 

For more than a decade, Bellona has been an active player chasing solutions to decarbonize the shipping industry – a sector that is inevitably linked with ports along the beautiful and diverse European coastline. Bellona is working to promote the development and implementation of solutions to three fundamental challenges to our environment: climate change, pollution and degradation of ecosystems.​ 

Ports2Decarb project manager Janis Volberts sat down with Norwegian colleagues Sigurd Enge and Irene Øvstebø Tvedten to share Norwegian insights on scalable solutions to reduce an estimated 4.7 million tonnes of CO₂ from the European ferry fleet. The discussion also addressed the challenges of long-distance shipping and the growing number of emission-intensive tasks now taking place in and around ports – underlining the message that emissions are a public responsibility. 

1. Could you walk us through Bellona’s work on the electrification of ships, particularly efforts to replace diesel engines with battery systems or hybrid solutions for longer-distance shipping? 

It has been a decade since Bellona helped to demonstrate that 24 m long sailboat Opal (see image at the top left of the article) can ship tourists from northern Iceland to Greenland powered by wind and electricity. Now more than 50% of all the ferries in Norway are electrified. This is the way to go as direct electrification is the most efficient way for zero-emission shipping in short and fixed routes. Electrified ships are now operational and connecting Oslo to Kiel as well as Norway and Sweden. They have been using shore power since 2011. 

In 2019, Color Line newbuild “Color Hybrid” came into operation with a battery pack of 4,7 MWh in a hybrid propulsion system enabling up to one hour of emission-free operation, and a charging facility in Sandefjord that charges the batteries every day. “Color Hybrid” is 160 meters long and has a capacity of 2 000 passengers and 500 cars. This demonstrates that hybrid-electric propulsion is scalable. 

In 2022, we built on our experiences and technological developments to conduct a new feasibility study on the European ferry fleet. The goal was to assess which existing battery-technology could be applied to different shipping cases and how they could reduce emissions across the Europe. The result of the study showed a potential emissions reduction up to  48%.  

2. Could you tell me more about shore power and its potential to reduce emissions, given that around 7% of a ship’s total emissions occur while docked at port? 

We estimated 7 percent port emission as an average stay in port for the sector as a whole. The first physical evidence of our work was in Oslo, where the Kiel ferry was in port in Oslo 4 hours a day, with around 3 000 tons of CO₂ annually were reduced, as a result of a cooperation between ColorLine, Hafslund (grid and energy actor), Oslo Port Authority and Bellona. They needed high voltage connection with 1,2 MW capacity to feed the consumption onboard while by the quay. The benefits are many; direct conversion from fossil fuel to electric hydropower, avoided air pollution in densely populated areas, protecting nature from air pollution in coastal areas, drastically reduced noise in port areas, cleaner nearby areas with no SOx, NOx and black carbon emissions.  

Simultaneously we engaged with the (International Standard Organization (ISO) working group for high voltage shore power connections. In 2011, Bellona was chosen as the convener for the working group and hosted one of the first gatherings in Oslo with the industry from many nations, including US, Japan, Germany and Norway. This collaboration between ISO, Institute of Electrical and Electronics Engineers (IEEEI) and International Electrotechnical Commission (IEC) with the name ISO/IEEE/IEC 80005-1/2/3, resulted in setting an international standard for high voltage shore power. 

After the first facility in Oslo in 2011, there was a long struggle to get this into the political agenda and the result today is that it’s rolled out based on an ENOVA support program which has used over one billion Norwegian kroner, and a number of projects for ferries, cargo ships, cruise ships, aquaculture, fishing boats, supply vessels and more. See  this map for locations and numbers. See ENOVA’s last  allocation of funds for projects (in Norwegian). 

In 2016, Bellona’s first publication on shore power was a feasibility study with an economic focus and the concept “The Port as an Energy HUB”.  

Today we know that shore power is not enough, as we need charging power to charge the batteries onboard too, including due to a much higher demand for capacity for route-going vessels. The good thing is that this technological concept can be applied to many more ships in short sea shipping than we thought before. Electricity is more efficient than any other energy carriers so electric propulsion should be chosen, when possible. 

3. What are the prospects for wind-assisted propulsion systems (WAPS), including technologies based on the Magnus effect, as viable solutions for decarbonizing the shipping sector? 

Wind was the main energy carrier until the coal fired steamships and later combustion engines became the new normal. Now we need a “new normal” once again, with sails and wind applications in focus again. Wing energy has the smallest environmental footprint for ship propulsion. It’s a competitive technology with zero energy cost. The cost is to manufacture and install the application, then you work with nature’s forces, not against them.  

In addition to traditional sails, several other concepts are currently being developed and tested.  The “Magnus effect” makes the rotor spin and gives the ship extra propulsion and can substitute up to 20 % of the needed energy. Together with rotor sails, there is rigid wing sail, soft wing sail, soft sail system (conventional sails) ventilated foil systems and kite systems. These systems can make the battery range extend even more and bring the ship, passengers and cargo safe to the port. 

Sigurd Enge was part of the Heyerdahl awards expert committee that awarded the prize to Wallenius Wilhelmsen for their plans to use wind-powered vessels for their cars and truck carrier (Link to the Norwegian Shipowner Association award announcement). 

4. Could you share the benefits of hull cleaning for ships, and how this low-tech solution contributes to reducing emissions? 

Bellona’s perspective is that frequent in-water cleaning of ships’ hulls, also known as proactive cleaning is a key method to address biofouling in the shipping industry. Biofouling is the accumulation of organisms on ships’ hulls, and has several negative environmental effects, including the potential transfer of invasive aquatic species organisms on ships’ hulls, and an increase in greenhouse gas emissions due to additional drag caused by the biofouling. In-water cleaning helps mitigate these environmental problems, and in the long run, may also lessen the need for toxic coatings as a way of preventing biofouling.  Today, the use of in-water cleaning is quite limited, partly due to stringent regulations at national and local levels.  

Allowing environmentally sound in-water cleaning should be part of the practices of any green port, especially those part of Green Corridors, since it reduces greenhouse gas emissions by at least 9 %, according to the IMO. Bellona has initiated an ISO standard on in-water cleaning, which will make it easier to approve in-water cleaning and oversee that in-water cleaning processes are conducted in an environmentally sound way.  

For more information on ship hull cleaning reach out to Irene Øvstebø Tvedten Senior Advisor Maritime at the Bellona Foundation irene.tvedten@bellona.no. 

5. What are the next steps Norway is planning to take to further reduce greenhouse gas emissions from the shipping sector? 

In Norway there is different kind of ship categories that need to decarbonize. The biggest contributors to GHG emissions are offshore supply vessels, fishing fleet, ferries and short sea cargo ships. The governments’ goal is to reduce the Norwegian overall emissions by 55 % by 2030. But we are not even close. 

The offshore (petroleum) supply fleet does have the economy, the ambition and a moral responsibility to cut their emissions significantly. They have invested in shore power, but it is not finished. They have projects on ammonia as fuel but are in the early stages and the reconstruction will take time and at a high price. And they need more ammonia than what’s available today. They will reach a 55 % reduction but “when” remains the big question. 

The fishing fleet, especially the ocean-going fleet, have long travel to the fishing ground and stay there for weeks and months so it’s a challenge to store enough renewable energy onboard. The price of reconstruction and energy makes it challenging to happen. Fishery is a renewable resource that needs radical changes to become sustainable.  In particular, the ocean-going fleet faces significant challenges in switching from fossil diesel oil to low or zero emission fuel. This comes on top of overfishing and fishing gear like bottom trawl that damages the seabed. But they will also be able to reduce by 55 %, the question is when.  

The car ferries are in the best position when it comes to switching to alternative energy and reduced GHG emissions and are close to 50 % reduction already, but the development has stopped because of higher prices and poor county economies and lack of governmental support schemes. So, the lead erodes if there are no new political incentives to continue. Emissions from the ferry fleet are “ours”, it is the public responsibility and needs to be addressed to our politicians, to make the emissions disappear.  

The short sea cargo ships have started many projects to reduce emissions by electrification and switch to zero emission fuels. It is possible to reduce it by 55 % but the barriers are in the ports, to get the needed energy for propulsion in every port with traffic in this segment.  

So, we need much more electric energy to charge ship batteries. That means electric energy to ports must be prioritized higher in the future. We need clear and predictable political demands for each sector of ships to be able to accelerate the green shift at sea. We must produce more alternative fuel to replace fossil fuels, and there must be cooperation in the Nordic countries to ensure there is the same quality of fuel and electricity in all ports. The Nordic coasts must be a long green corridor of sustainable solutions! 

6. What about the deep-sea ships? 

In the first week of April there was a meeting in the IMO about emissions from the international shipping fleet. They made a historic agreement to define fuel quality and implement economic measures to equalize the prices between fossil fuels and zero emission fuels. That’s good news but there is still work left to make the details clear and strong enough to bring us to zero emissions from shipping by 2050.  

So, our job is to detect the smartest logistical, technology and policy solutions and fight for them! 

To reach the ambitious goals for 2030 and net zero for shipping sector by 2050 Bellona recommends the following: 

1. On political landscape level national governments need to strengthen incentives to help speed up investments in ports, ships and related infrastructure.
   • Council Regulation (EEC) No. 3577/92, 7 December 1992 
   • States can conduct public service contracts to ensure reliable transport to/from/between islands.
   • Gives opportunity to impose requirements for emission reduction 
   • The main success for electrification in Norway – 70 electric ferries in 2022. By end of 2024 the number of ferries is close to 80 but the transition has slowed down the few last years caused by economy of the counties and inflation.  
   • Proposed FuelEU Maritime requires ships over 5 000 GT to reduce the GHG intensity, increasing over time to secure the track to zero in 2050. 
   • The offshore petroleum service vessels need to get clear requirements for their GHG reduction to maintain their “license to sail”.
   • The production of alternative fuel, like hydrogen or ammonia needs to be planned according to the demand.
   • The deep sea fleet need a GHG agreement in IMO that is strong enough to make alternative fuels to compete with fossil fuels.

2. For the short sea shipping fleet should go electric, when possible, and all ports with short sea vessels need to establish electric charging capacity. Ferries can be fed with electricity from shore by:

• The local and regional electric grid needs to be upgraded to be able to support the demand from battery-electric propulsion vessels 
• Part of the general electrification of all fossil energy use 
• Stationary battery packs will speed up charging 
• Battery packs will relieve the net by «peak shaving» the load 
• Install solar panels on nearby buildings 
• Install wind turbine on shore and offshore 
• Strengthen the grid to feed both other ship types and land transport 
• Make onboard heat and other energy use more energy efficient 
• New built ferries in light weight (aluminum, carbon, etc.) materials reduces energy use 

3. Ports play a key role for proactive hull cleaning. In the absence of international regulations, they should act individually to be part of Green Corridors.

Check out the recent launch of Bellona’s Center for Marine Restoration in Lofoten. 

For questions, please contact:  

• Janis Volberts: janis@bellona.org  
• Sigurd Enge:  sigurd@bellona.no  
•  Irene Twedten: irene.tvedten@bellona.no