Port electrification

What is port electrification and what are the key elements for the port energy transition?

Port electrification will be key to the energy transition of shipping. This mode of transport is highly efficient and comparatively sustainable compared to others, but it still needs to innovate in its management and energy sources to reduce emissions. Solutions such as Onshore Power Supply (OPS) facilities offer a promising new scenario.

An image from the pioneering ScottishPower study Electrification of Service Operation Vessels in the offshore wind sector.

Maritime transport is a key part of the supply chain for many industries. It is also essential for international trade and as a means of passenger transport, whether for short, medium or long distances. It is the most efficient and cost-effective way to move large volumes of goods and oversized cargo globally, with a lower carbon footprint per tonne transported than other modes of transport.

However, the sector remains responsible for a significant share of global greenhouse gas (GHG) emissions, taking into account the full journey of a vessel from its port of departure to its port of arrival, including its stay in both.

The electrification of maritime transport, starting with ports, represents both a challenge and an opportunity in the transition towards a more decarbonised, efficient and secure energy future.

A report from the International Transport Forum forecasts that, if no action is taken, CO₂ emissions from ships could reach 1.09 billion tonnes per year by 2035. In the European Union (EU) alone, maritime and port activity accounted for 137.5 million tonnes of carbon dioxide in 2022, representing 14.2% of transport emissions, almost equivalent to the aviation sector.

Since 2024, the EU has required the maritime sector to progressively decarbonise and, from 2030, will require ships to electrify their demand while at berth.

Industries that are difficult to decarbonise

Types, characteristics and challenges.

Hard-to-abate sectors

How do microgrids and other technologies drive port electrification?

The adaptation and electrification of ports is a fundamental and leading step in the energy transition of maritime transport, enabling more efficient, cleaner and more autonomous energy management. While electrifying vessels themselves — whether recreational, commercial or fishing — remains costly, there are multiple land-based solutions already being implemented that have a direct impact on reducing sector emissions while also cutting noise levels and improving wellbeing in nearby communities.

For example, the new shore-side power supply technology known as cold ironing or Onshore Power Supply (OPS) enables ports to install infrastructure that adapts the voltage and frequency characteristics of onshore electricity to those of ships, supplying them with power from the electrical network while they are berthed.

This allows ships’ auxiliary engines, which are essential for powering refrigeration, heating, lighting, loading and unloading systems and emergency systems 24 hours a day, to be switched off, thereby reducing pollutant emissions and noise.

Another way to accelerate the decarbonisation of terminals is by electrifying cargo handling equipment (CHE) used to move containers on and off ships in freight ports. The global CHE fleet is estimated at more than 120,000 units, so replacing diesel with clean energy sources would have a significant impact in creating greener ports.

Microgrids and smart grids also play a key role by integrating renewable sources, controlling demand in real time and ensuring a constant energy supply in ports even during peak loads. What’s more, battery energy storage systems (BESS) allow excess electricity generated – for example during periods of high wind or solar output – to be stored and used when needed, optimising consumption and reducing dependence on the central network.

Finally, the emerging use of fuels such as green hydrogen or green methanol offers sustainable alternatives for heavy machinery or working vessels, completing a comprehensive energy transition in ports.

The challenge of efficiently storing power

What impact will the electrification of the port sector have?

Port electrification will have a transformative global impact by drastically reducing pollutant emissions generated by berthed ships and port machinery.

As well as supporting the sector’s decarbonisation and reducing its environmental footprint, it will have a direct positive effect on the health of people who work or live in port areas, lowering respiratory and cardiovascular diseases.

For the industry, it represents a strategic opportunity to modernise operations, reduce long-term operating costs through the use of clean and efficient energy, and comply with increasingly strict environmental regulations. It also drives technological innovation and opens the door to new investment in smart infrastructure such as microgrids, storage systems and fast chargers.

These solutions are further complemented by solar self-consumption systems, which enable 100% renewable energy to be generated on the rooftops of port buildings, delivering significant savings on electricity bills.

How is Iberdrola driving port electrification for decarbonization?

In recent years Iberdrola has positioned itself as a leading partner in the development of OPS or cold ironing facilities in Spain, with major projects in ports such as Vigo, Alicante and Pasaia, which is scheduled to become operational in 2026. The network electricity supplying these new infrastructures to vessels at berth – replacing that generated by their fossil-fuel-powered auxiliary engines – comes from 100% renewable sources in the company’s projects. This further enhances emission reductions beyond the port areas themselves and, together with reduced noise pollution, generates a visible, measurable and significant positive impact.

Iberdrola’s active role in port electrification is also reflected in the partnership between Iberdrola España and Marinas de España, an agreement to promote the electrification of marinas nationwide with the aim of reducing their dependence on fossil fuels and driving a transition towards sustainable shipping.

Another key initiative by the Iberdrola Group, aligned with the objective of decarbonising marine operations, is being led by its UK subsidiary ScottishPower. In collaboration with Stillstrom, ScottishPower Renewables has presented the pioneering study Electrification of Service Operation Vessels, which demonstrates the technical, economic and operational feasibility of using battery-powered operation vessels for the maintenance of offshore wind farms.

These vessels, which could be charged directly using energy generated by the offshore wind turbines themselves, would be able to operate for up to 18 or 19 hours per day without emissions, significantly reducing greenhouse gases.

What challenges does maritime electrification face?

Large-scale electrification of commercial vessels remains a pending challenge, although there are increasingly successful initiatives that serve as inspiration for innovation in the sector. Examples include the Yara Birkeland, the world’s first fully electric cargo ship, which began commercial operations in Norway in 2022, and China’s Green Water 01 container ship, which is capable of transporting 10,000 tonnes using exclusively electric power.

Below are some of the main challenges facing maritime electrification, which also represent opportunities.

Technical challenges:

Increasing battery capacity

Current batteries have not yet developed sufficient autonomy to power large ocean-going vessels without the possibility of recharging.

Battery weight and size

The size of current batteries takes up considerable weight and space on ships, reducing cargo capacity and therefore potential profitability.

Charging time

Charging a ship’s battery takes significantly longer than refuelling with fossil fuels, which may affect schedules and port stay costs.

Political and regulatory challenges:

Lack of clear international standards

Globally, there is still no unified regulation requiring or incentivising the use of electric ships or green infrastructure in ports, although some countries are developing their own decarbonisation plans.

Inequality between countries

Not all countries involved in international maritime trade have the same economic or technological capacity to invest in electrification, which slows global progress.

Legal pressure on operators

In some places, legislation still allows ships to use polluting fuels without paying a fair price for that pollution.

That said, in 2025 a historic milestone was reached with a global agreement to address shipping emissions after almost 10 years of negotiations. Driven by the International Maritime Organization (IMO), the agreement covers the vast majority of global commercial maritime transport and means that, from 2028, shipowners will have to use increasingly cleaner fuels or face financial penalties.

This development offers hope that the maritime transport sector will take decarbonisation seriously and firmly commit to innovation and reinvention as the necessary path towards sustainability.