Next-generation warships help protect the Fleet – and the environment

Giant ‘catalytic converters’ are being fitted on the Navy’s new generation of warships to dramatically reduce their impact on the environment.

Harnessing technology used in diesel cars and trucks – but on a much grander scale – Type 26 frigates, led by HMS Glasgow, remove many of the harmful elements from engine exhaust gases.

It will allow the submarine-hunting ships – which enter service in the second half of the decade – to operate in some of the most environmentally-sensitive parts of the world as well as meet the standards set in heavily-regulated waters such as the North Sea and off the Eastern Seaboard of the USA.

A version of the system has already been fitted to the Royal Navy’s two newest patrol ships, HMS Spey and Tamar.

The duo are on a five-year mission to patrol the Indo-Pacific region, including operating in some of the most remote, unblemished regions of the planet.

Minimising their environmental impact was a key factor in their construction – and is now being built upon in the next generation of warships now taking shape at BAE Systems’ yard at Govan on the Clyde.

To mark British science week, the team are keen to trumpet the growing green credentials of the future Fleet.

HMS Glasgow and her seven sisters are being fitted with Selective Catalytic Reactors – a box about three metres tall and two across equipped with large-scale filters/converters.

As exhaust fumes from the diesel generator passes through, a urea solution is sprayed in which causes a chemical reaction to reduce the majority of nitrogen oxides emissions.

Instead of the gases – harmful to the ozone layer, a key component of acid rain and a factor in global warming – the process instead produces water and oxygen.

“The urea we will use is effectively the same ‘Adblue’ solution that you see sold in fuel station forecourts for trucks and vans,” explained Commander Richard Wadsworth, a senior marine engineer officer with the Type 26 frigate programme.

“It thermally decomposes in the hot exhaust and reacts with NOx to produce water and nitrogen. It reduces NOx emissions – which is good for the environment.

“It means that the Type 26s will be ‘IMO Tier III compliant’ for NOx emissions and will be able to operate worldwide including in several ‘special areas’ which have higher emission regulations.”

And if you were wondering… The urea comes not from the crew – or any other living creature with a kidney – it’s not the correct purity or concentration. Instead it’s manufactured as a special solution and delivered to the ships.

The catalytic reactors are part of a wider programme of enhancements and improvements to reduce the impact of the Navy’s operations on the environment,

Aircraft carrier HMS Prince of Wales is fitted with the Fleet’s first pyrolysis plants which turn 150kg of waste into just 1½kg – or one and a half standard bags of sugar.

And underlining the ‘environmental credentials’ of Spey and Tamar – which proclaim to be the ‘greenest ships in the Navy’, all ballast water taken on board is treated with ultraviolet light to sanitise the water which means the ships won’t carry invasive species around the world in their tanks.

And the waste water produced – known as ‘black water’ – is broken down by bacteria and discharged safely into the ocean as clear water… so clean it is supposedly good enough to drink (although no-one aboard has dared try it).