M55 The Electric Ship
by George Paloczi-Horvath
INTRODUCTION
It was announced on 1 August last year that the UK and France are to collaborate on research which could mean the next generation of warships and submarines will be powered by electric engines. The Ministry of Defence said that electric propulsion has clear potential advantages over existing diesel and gas turbine technology.
The ship can be powered by fewer, more efficient engines, leading to a lower initial purchase price and lower fuel, operating and maintenance costs through its service life. Large machinery spaces will no longer be needed, allowing more space for weapon systems and accommodation. Ships will be more operationally effective, better places to live and work – and more stealthy.
Potential savings in operating and maintaining ship power and propulsion systems could total up to £1 billion, the DPA says, adding that its experience with Type 23 frigates, which use electric drive for ultra-quiet operations when sonar arrays are deployed, is especially useful to the development of the electric ship.
Defence Procurement Minister Baroness Symons said' "the introduction of electric ship propulsion may be as significant as the change from sail to steam. It could mean the warships and submarines of the future would be more effective, would be better places for their crews to live and work on, and would be built and operated at a lower cost to the taxpayer.
"The results of the technology development programme will give us the information we need to use electric propulsion as the baseline against which other propulsion systems will be judged," Symons added. "If the prime contractors for the Future Surface Combatant, the Future Attack Submarine or the Future Aircraft Carrier wish to use an alternative they will have to demonstrate that their proposal is better. This means we will be able to ensure that our future ships will have the best possible propulsion systems," she said in a broadside against opponents of the new technology.
THE UK POSITION
The MoD and the French Government has funded an electric ship technology demonstrator which will test the practicality and effectiveness of the new concept. ALSTOM Power Conversion won key the £19 million contract to design, build and operate the demonstrator at their research centre at Whetstone, near Leicester.
If electric technology proves effective, it could power the Future Surface Combatant (FSC), the Royal Navy's next generation warship; the Future Attack Submarine, and the Navy's two new large aircraft carriers.
The Type 45 destroyers are needed too urgently for electric drive to have been fully developed in time (starting from 2007). They would instead have traditional gear boxes and shaft lines.
However, another project will still probably take centre stage with Type 45 - Integrated Electric Propulsion (IEP), which would be a development of technology used in the new assault ships Albion and Bulwark. IEP would use an induction motor, but is still the subject of technology demonstrator programmes which will be evaluated against more conventional options.
Type 45 using IEP would be powered by high speed gas turbine alternators which could provide about 40 megawatts - about the amount of power needed by a small town - to drive the ship and provide all other services. Two diesels would provide power for low speed operations. Type 45's baseline design can already accommodate IEP, the DPA says. The DPA also says that IEP would allow the ship to cruise at low speeds on its diesels or just one gas turbine, with the whole electric ship systems being used in combat or in an emergency.
But the CVF may be different, as the possibilities of electric drive provide the option of dispersing the powerplant around the ship and the first CVF is not required until 2012.
A preceding demonstrator project (IFEP) had been planned for 2001 - 2004 with the MoD providing major items of equipment like the WR-21 gas turbine, which will still be used on Type 45 and completed its development test phase last June. The IFEP project was to
bring together the development of advanced cycle gas turbine alternators and "power dense" electric motors in the prototype IFEP system which, now as IEP, will run for the first time next year.
The IFEP plan was that the gas turbine alternators to provide a single source of power for the electric motors driving the ship and power all the electrical services. Technologies compatible with the electric ship might include podded drives, with a powerful electric motor fitted in a steerable pod beneath the hull and fuel cells operating directly from diesel fuel. The Defence Evaluation and Research Agency is developing a fuel cell system of this type. All this work is being subsumed into the IEP project.
US PROGRESS
Last July the US Office of Naval Research awarded Florida State University (FSU) contracts worth $10.9 million over three years to research and develop the electric drive and integrated power systems that are expected to propel future warships.
The new technology is expected to revolutionise the US Navy's combat capabilities by improving combat effectiveness, while reducing operational costs and crew size, the FSU said. All electric ships of the future, like the DD-21 Zumwalt class land attack destroyer, will help the US Navy realise major cost savings and reduced crew levels by automating many functions now performed by sailors.
In present US warships, propulsion systems use up to 90% of a ship's capacity. All electric ships are intended to free hull space, reduce a ship's weight, increase payloads, and allow greater design flexibility. Eliminating hydraulics and compressed air is also supposed to lead to cleaner, quieter, uninterruptible and re-configurable electric power systems. New systems are hoped will allow the US Navy to take advantage of future direct energy conversion sources, electric weapons, and advanced sensors and defences.
"This is a major transition that will build a navy... which is fundamentally stronger than the navy of the past and better-adapted to seize the opportunities of the future," said the then US Navy Secretary Richard Danzig. "The architecture of our ships will change dramatically as will the conditions under which our sailors operate and the way we go to sea. Electric drive will change the character and power of our forces in revolutionary ways," Danzig added.
While research and development of next-generation ship propulsion will be a major focus at the FSU Centre for Advanced Power Systems, US Navy and FSU scientists expect equipment and systems developed at the centre to have broader applications in the aerospace and commercial industries as well as civil electric utilities. (The FSU Centre for Advanced Power Systems is made up of scientists at the FSU, the National High Magnetic Field Laboratory in Tallahassee, the Florida Agricultural and Mechanical University, the FSU College of Engineering as well as other academic and industrial participants).
One way or another, it is clear that the day of the electric ship is almost upon us.
Disclaimer
The views of the author are his/her own. The UK Defence Forum holds no corporate view on the opinions expressed therein. The Forum exists to enable politicians, industrialists, members of the armed forces, academics and others with an interest in defence and security issues to exchange information and views on the future needs of Britain’s defence. It is operated by a non-partisan, not for profit company.
February 2001
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