BAE Systems is installing a centralised shore-to-ship power conversion solution at Her Majesty’s Naval Base (HMNB) Portsmouth. Ian Render, ABB’s Senior Project Engineer, explains how the Static Frequency Converter (SFC) solution will help to enhance the overall efficiency of the Navy Base while minimising its environmental impact.
The naval base is spread over 150 hectares and has 10 kilometres of waterfront. It is home to almost two thirds of the Royal Navy’s surface fleet, including frigates, the Fishery Protection Squadron and the new Queen Elizabeth Class aircraft carriers.
As the contractor responsible for the dockyard’s electrical systems, BAE systems has turned to ABB for a shore-to-ship power conversion solution to provide power to high power consumption vessels when they are in port. This allows them to switch off their diesel engines and is called cold-ironing.
Frequency conversion is essential in cold-ironing to convert the power supply from the 50 Hz of the UK’s national grid to 60 Hz. This is the standard frequency for on-board electrical distribution systems established by NATO and adopted by the commercial shipping sector.
Previously, frequency conversion at Portsmouth was carried out by a scheme of rotary frequency converters (RFCs). These are complex mechanical systems that combine motors, generators and drives, as well as regulation and control equipment. However, these were nearing the end of their service life and BAE wanted to adopt the latest solid-state power electronics technology.
ABB is delivering a package for BAE Systems based on medium voltage SFC technology and integrating a dry-type 11 kV to 6.6 kV transformer as well as control equipment to interface with the dockyard’s electrical management system.
The power electronics solution offers the major benefit of having no moving parts apart from its cooling fans. The SFC has high reliability, efficiency of more than 98 percent and minimal maintenance requirements, leading to lower costs per megavoltampere (MVA).
As a result, the new power supply will enable the dockyard to benefit from savings of up to 25 percent.
Whereas in commercial ports, cold-ironing is usually achieved with individual conversion stations for each berth, the solution at HMNB Portsmouth will use a central conversion system that feeds the entire shoreside network.
The SFC is rated at five megavoltamperes (MVA) with a peak load of seven MVA. It can switch on instantly, unlike an RFC that needs to be run up to speed. It is also able to handle much higher fault levels – 10 megawatt (MW) for 1 second.
Her Majesty’s Naval Base Portsmouth
Shipping and the environment
When the International Maritime Organisation Data Collection System (IMO DCS) comes into force in January 2019 it will be the first monitoring and reporting system for emissions from the world’s shipping fleet.
The new global regulation builds on the EU’s introduction of the Monitoring, Reporting and Verification (MRV) regulation in European waters in January 2018.
What both regulations share in common is that by gathering data on fuel consumption and CO2 emissions, they will provide a platform for port and shipping operators to improve their environmental performance.
Shipping carries around 90 percent of the UK’s goods and even though it is the most carbon efficient form of freight transport, the sector accounts for more than two percent of the world’s CO2 emissions, with a quarter of that being contributed by passenger services.
Cold ironing is an area with good potential to reduce the environmental impact of the sector. It is a relatively new trend for merchant fleets but is well established in naval dockyards around the world.
Not only is it a good opportunity for ports to reduce their emissions of CO2 and reduce the impact of noise and vibration on the local environment, but it also enables shipping operators to save on emissions and fuel consumption
