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Fjellstrand electrifies offshore wind service vessels

Fjellstrand converts diesel-powered service vessels to electric hybrids, reducing costs and emissions in the offshore wind industry. “We provide a win-win solution that takes our new electric ferry technology and applies it to other industries,” says Edmund Tolo, R&D and Sales Manager at Fjellstrand.Published 18 Nov 2022 (updated 7 Feb 2024) · 3 min read
Norside Supporter

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At a glance

  • Green battery systems for e-hybrid service vessels
  • Converts diesel-powered vessels for offshore wind use
  • Reduces fuel use, costs and emissions

Offshore wind energy and other renewables are undercutting fossil fuels as the world’s cheapest source of power. To keep this momentum going, the offshore wind industry continues to decarbonise its operations, both to reduce its own operational costs and to meet stricter environmental standards.

One stumbling block is the industry’s use of diesel-powered service vessels. “Wind farm operators cannot simply toss aside these expensive vessels. At the same time, the oil and gas industry has similar vessels going unused. Conversion and electric hybridisation is the answer,” says Tolo.

Offshore wind vessels get electric upgrade

Fjellstrand installs green battery systems in service operation vessels (SOV) for the offshore wind industry. In many cases, the original vessel was used in the oil and gas industry and then converted for a new purpose in a new market.

“We draw on our experience in battery installation on newbuilds,” says Tolo. Here he is referring to Fjellstrand’s delivery in 2015 of Ampere, the world’s first battery-operated car ferry, and Medstraum, the world’s first fully electric, zero-emission fast ferry, named “Ship of the Year” in 2022.

Moreover, Fjellstrand has the equipment and facilities to carry out the task. Using cranes and lifts, vessels can be lifted ashore and moved into a production hall for conversion without weather disruptions.

The shipbuilder also upgrades SOVs with walk-to-work gangways and other equipment. Other types of vessels are converted and upgraded as well. These include car ferries, fast ferries, and survey and seismic research vessels.

Fjellstrand installed and integrated an 896-kWh battery pack as part of the conversion of Norside Supporter into a wind farm SOV.

Huge cost cuts with Fjellstrand’s e-hybrid

Fjellstrand’s battery technology enables vessels to run on three engines instead of four. “This, along with other modifications, reduces a vessel’s emissions and power consumption by 20 to 25 per cent,” explains Tolo.

As a result, electric hybrids have lower operational and maintenance costs, including less use of lubrication oils.

Moreover, the solution extends the life of older, diesel-powered vessels. “After the drop in oil prices in 2015, we saw a number of oil and gas vessels sitting idle. We gave some of these new life through electric hybridisation and other upgrades,” says Tolo.

Electric hybrid vessels take off

The EU is scaling up offshore wind energy as part of its strategy to reach climate neutrality by 2050. Many countries are putting similar focus on wind energy to achieve energy independence and sustainability.

“Our market for green SOVs follows the offshore wind market. More wind farms are being built farther from shore, and the industry will have an increasing need to reduce fuel, operational and maintenance costs by hybridising service vessels,” says Tolo.

Established in 1928, Fjellstrand offers newbuilds, vessel conversion, battery installation for hybrid vessels, general maintenance and shipyard services.



Omavegen 225, 5632 OMASTRAND, Norway


Edmund Tolo

R&D / Sales Manager

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