Shipping poses a particular challenge for decarbonisation, including for offshore projects. Solving this riddle will be crucial.

Energy companies demand that contractor-provided vessels meet sustainability targets.

Vessel providers must “prove they’re doing what they can”, Energy Solutions managing director Paul Holland said.

Tidal Transit co-founder Leo Hambro said there was pressure across all industries to decarbonise.

“In some ways, it could be even more important for wind to become circular and sustainable because this industry is one of the main driving forces behind electrification and net zero; all eyes are on wind to set the greatest example of how to transition to clean, emissions-free energy and in a sustainable way,” Hambro said.

A first step in tackling decarbonisation is moving from hydrocarbons to hybrid power. A crew transfer vessel (CTV) emits 999.1 kg of CO2e per hour while in transit, falling to 405.9 kg while loitering. For a service operation vessel (SOV), this rises to 2,775.4 kg and 333 kg respectively.

Hybrid hopes

Using a battery onboard can help cut emissions when loitering. Holland explained that hybridisation “works when there’s significant variability in power requirements”.

The challenge for a vessel moving from port to offshore facilities, such as a wind turbine, is the variation.

“It may be operating to harbour limits, then accelerate away to an offshore site where it will loiter for hours. Effectively, it’s a taxi service. There’s scope for integrating hybrid power,” Holland said.

Batteries can provide power in the harbour and while on station. When the ship is fully underway, it runs on diesel.

“There’s an advantage in just loitering. At this point, if you’re burning diesel, the engines aren’t working hard enough. As a result, you get soot and diesel particulates and NOx emissions because the engine doesn’t reach the heat required to clear this.”

While hybrid power does not fully provide decarbonised maritime transport, it has an impact.

“Things are changing. It’s very rare there’s no opportunity to improve efficiency. We just need to look to make improvements where we can and then we start to make an impact on the overall problem.”

Costing the change

Companies want to show progress on sustainability targets. But do the sums add up in moving away from diesel to hybrid or battery power?

Holland said there was a two-fold benefit. The use of batteries saves fuel, and emissions, and reduces engine running time.

“The cost of servicing these engines can be significant and a service interval may be as little as 500 hours. If you’re running the engine for 10, or 12, or 18 hours a day, you reach that 500 hour mark alarming quickly,” he said. When it is idling, there is a low return on expense.

Hybridisation allows the engine to last longer, be more efficient, while reducing fuel and service costs.

Holland acknowledged an “additional cost of electrification”, while stating these were falling. He said costs have fallen by 20-40% per year.

Batteries for maritime uses tend to be lithium iron phosphate. The trade-off is that while this is seen as safer, it is less energy dense than other options.

*Hybrid onboard power systems. Source: Energy Solutions*

Full electrification is more of a challenge. Hambro noted the industry’s continued reliance on diesel. “Alongside the capital and time expenditure required to make the transition, the supporting infrastructure, like onshore and offshore charging, is not yet at a stage where transitioning to a fully electric fleet is entirely feasible.”

Further into the future

Holland acknowledged that hybrid power is a first step towards cutting emissions. Moving to longer distance autonomous vessels would require alternative technologies, like e-methanol.

Methanol is gaining ground. The UK Shipping Office for Reducing Emissions (UK SHORE) programme has recently funded “green corridors”, involving methanol, between the Port of Tyne and the Netherlands’ IJmuiden, in addition to studying the Dublin-Holyhead route.

UK SHORE faces criticism for lacking objectives and questions over its continued funding. This is an area where industry is seeking clarification from government at the upcoming budget.

There is talk of hydrogen, but it lacks energy density and costs – for clean options – are high.

“It’s early days with hydrogen and you can also just use that as short code for expensive,” Holland said. “Time will start to erode that price premium.”

He continued that hydrogen fuel cells would benefit from hybridisation. These are “not very good at picking up significant step load increases. Using a battery as part of the system, where the battery can pick up instantaneous demand and then hand back to the fuel cell, works really well.”

Another option that has taken some recent attention is a move to sails. This week, Drax Group agreed to provide £1 million for the FastRig technology, in partnership with Smart Green Shipping. This technology claims to reduce emissions by 30%.

Port in a storm

Ships can tackle emissions in port. Vessels need power while moored for heat and lights for the crew.

The obvious solution is to link vessels to the distribution grid in a process known as “cold ironing”, given proximity to shore power.

Unfortunately, this is not as commonplace as it could be. Holland cited an instance where vessels delivering goods between Scandinavia and the UK run generators constantly, because neither port has the needed infrastructure.

“We are starting to see there are some ports that are making good progress, but it’s not universal by any means,” Holland said.

By 2030, the European Union will require larger ships to connect to shoreside power in certain ports.

NatPower Marine aims to tackle this problem with a £3 billion investment in 120 ports to achieve electrification by 2030.

Stefano Sommadossi, CEO of NatPower Marine, described port electrification as “vital in the move to decarbonisation. It can be utilised for cold ironing or propulsion, where an electric engine is the source of power to propel the ship.”

Sommadossi said one sixth of shipping emissions are produced while vessels are berthed and running on auxiliary engines.

“Infrastructure at ports is vital to enable the switch to zero carbon electric ships, which are considered an important potential way for the industry to reach net zero emissions by 2050.”

Hambro said the greatest challenge in the move towards electrification was a lack of charging infrastructure. “While portside charging by itself is relatively limited, the ability to charge onshore is really only half of the equation: to reach 100% electrification, vessels must also be able to charge at sea.”

The Tidal Transit director said integrating offshore charging would be crucial. This would allow “vessels to plug directly into wind turbines through both fixed and floating solutions, allows them to harness the unlimited renewable energy directly from source and with very high efficiency. This greatly extends vessels’ time on the water and unlocks wider areas of the sea serviceable by zero-emissions maritime.”

Making the connection

The challenge is always growing from existing levels. New electricity demand sources will pressure the existing grid and generation, which is already struggling.

NatPower has proposed its solution. Its sister company NatPower UK is developing onshore GigaParks, which will house around 20 GW of clean power.

These “will be supported by a total of 60 GWh of battery storage capacity, crucial for balancing intermittent demand – such as the demand from electric ship propulsion and cold ironing. These GigaParks will provide stable clean electricity to NatPower Marine’s UK port network via direct Power Purchasing Agreements [PPAs], or private wires,” the CEO said.

The UK Chamber of Shipping has called for a review of grid capacity availability in serving ports in 2026. Authorities should also commit to equalising tax treatment for electricity to make it a viable alternative fuel for shipping, the chamber said.

Sommadossi explained that ports cannot compete on price and are struggling to reach a critical mass.

“In a nutshell: It is not convenient and too risky for ports to manage electricity as a fuel. Just as ports prefer making money out of the logistics of carbon-based fuels rather than drilling, extracting, refining and selling it to shipping lines themselves, they could make money out of the logistics of electric fuel too – by entering into agreements with NatPower Marine,” he said.

NatPower announced an agreement with Peel Ports to create green shipping corridors to Ireland.

Tidal Transit’s Hambro called for more focus on circularity. Last generation technologies, he said, can be reused and recycled.

“Batteries, for example, can be given a second life onshore as port charging solutions, while vessels that have already seen years of service can be retrofitted to run on battery power, thereby expanding their lifespan by many years and offering thousands of nautical miles’ extra service.”

Take the plunge

Hybrid power for ships is an obvious initial approach for vessel and offshore facility owners. It addresses the significant decarbonisation issue with an initial step.

There’s a need for a greater vision. Companies look to government for big picture thoughts, but capacity is limited and the new administration has challenges to tackle.

Research into alternative power to reduce transit emissions is needed. Hydrogen may not be the first choice, but there are other ways to drop-in fuels, like biofuels.

Drax’s support for sails is another area of interest. Smart Green Shipping’s FastRig can be retrofitted onto existing vessels and start cutting emissions. This is similar to hybridisation. It does not achieve complete decarbonisation, but demonstrates willingness and interest.

Ports are an essential component of the puzzle. This should be easiest, given construction is more straightforward onshore than off. However, port expansion plays into those bigger challenges, like grid connections, needing systemic change.

Installing a battery or sail, ordering new engines are all steps that individuals can take. Developing onshore infrastructure and avoiding the complications of the grid queue and other such woes requires a much greater degree of co-operation and support.

NatPower’s plans can cut the Gordian knot, but the sector needs more such investments.

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