SOVs should ‘go electric’ to avoid GHG emission costs

On 1 July 2026, the UK Emissions Trading Scheme (ETS) reached the maritime sector, and offshore wind developers should be paying attention, as Sune Strøm* explains

The service operation vessels (SOVs) servicing UK windfarms are about to feel a new cost pressure that has nothing to do with turbine output or capacity factors. Carbon emissions from these vessels are no longer an environmental consideration alone, they are becoming an operating cost that developers and their supply chains need to plan for.

The UK ETS is not a new concept. Power generators and heavy industry have operated within it since 2021. The principle is straightforward – a cap is set on total emissions across covered sectors, operators must surrender one allowance for every tonne of CO₂e they emit, and the cap reduces over time.

What is new is that vessels of 5,000 gross tonnage (gt) and above are now entering the scheme for domestic UK voyages, with greenhouse gas (GHG) emissions included alongside those generated during transit. Every tonne of MGO burned on a vessel at berth, idling at sea or during a voyage will emit more than 3 tonnes of CO₂. The statutory civil penalty carbon price for 2026 is set at £49.41 per tonne.

While the market price for allowances will fluctuate, the direction of travel is clear, and emitting carbon carries an increasingly measurable financial consequence. For example, over the course of a year, a ship burning around 1,500 tonnes of MGO emits around 4,800 tonnes of CO₂e. If a vessel owner ends up paying the current statutory rates, then the use of 1,500 tonnes of MGO will add a yearly additional cost of £240,000, before accounting for the fuel itself (and assuming the penalty price is in effect). Across a fleet, those costs quickly become material.

Offshore windfarm owners in UK waters who are using the larger SOVs for daily maintenance, will also come into scope for UK ETS costs from 1 January 2027. The solution, however, is closer to hand than it might appear. By switching from fossil-fuelled ships to battery-electric vessels (e-SOVs), developers and their vessel providers can eliminate those GHG emissions at source, charging onboard batteries by tapping directly into the offshore wind farm’s own power production. Implementing a ‘wind-to-ship’ model not only avoids GHG emissions and associated costs, it also cuts exposure to oil price volatility and the geopolitical pressures driving it up.

UK ETS does not distinguish between a vessel making progress and one running generators alongside a quay or at anchor – a tonne is a tonne. That creates a direct financial incentive to reduce GHG emissions during idle and service periods, not simply just while their journey is underway.

Broader maritime electrification is just like the example of switching to e-SOVs, a solution for many vessels to avoid GHG emissions. Every period a ship can connect to zero or near zero carbon electricity instead of running auxiliary diesel generators minimises both fuel consumption and the number of emissions allowances that must ultimately be surrendered. As carbon pricing becomes embedded across maritime, the value of that operational flexibility will only increase.

The UK ETS threshold currently sits at 5,000 gt. It would be a mistake to treat that line as a target to stay just beneath. The UK Government has already consulted on extending the scheme to international voyages from 2028, and a review of the gross tonnage threshold is scheduled for the same year. Vessels below 5,000 gt are not outside the direction of policy, they are simply only outside its current scope. That is a distinction, but probably not a permanent one.

More fundamentally, the North Sea is undergoing significant change. Offshore wind energy represents one of the largest concentrations of marine activity anywhere in the world over the coming decade. This development it will unlock power supplies at large scale not only onshore but also offshore and thereby enabling maritime electrification both in ports and at sea.