A small device which emits tiny vibrations from the hull of a ship is a “game-changer” in the fight to make container vessels more environmentally-friendly, its developer has said.
When barnacles, and weed and mussels, make their home on the hull of ships, they create drag – or resistance, which makes it harder for the vessels to move through the water.
That means they have to burn more fuel, and emit more carbon dioxide (CO2).
As research associate Andrea Grech La Rosa puts it: “It’s like trying to make your way through water with lots of clothes pulling you back”.
He spends his time investigating the different ways to increase the efficiency of ships in the University College London tow tank.
“Algae, barnacles, these are all to the detriment of the hull because the once smooth hull is going to be rougher, it will disturb the flow. This is a direct drag that’s working against the ship.
“So, the less algae or barnacles you have on the hull, the better the fuel consumption will be.”
In fact, the International Maritime Organisation – the UN’s governing body for shipping and the seas – estimates that a vessel could burn 55% more fuel, with emissions 55% higher as a result, with barnacles covering just 1% of its hull.
That shows the difference a few shells makes.
Even a layer of slime as thin as half a millimetre covering 50% of a ship’s hull surface could increase its greenhouse gas emissions by 20-25%.
It’s an issue that Mr Grech La Rosa says is compounded by increased consumer demand.
“We want ships to be delivering our items at the same rate, without making larger ships, the only alternative is to go faster. And that means that having fuel efficient ships is critical to ensure our emission levels are low.”
Currently, the industry relies on anti-fouling paints, with agents that kill these organisms, but these biocides are toxic, and can shed microplastics as well, so have an environmental impact.
And sooner or later, the paint will wear off and the ship will have to be hauled out, cleaned, and repainted.
Small speaker fixes on to hull and vibrates
Even hauling a small boat out of the water can cost thousands of pounds, and risks spreading invasive species around the world’s oceans.
But, Coventry-based Sonihull may have the answer. The company has developed what is effectively a small speaker that fixes on to the hull of boats and vibrates.
The tiny vibrations, too small to interfere with sonar equipment on boats, or indeed with marine life, create tiny bubbles around the hull.
When those tiny bubbles implode they destroy the single-celled organisms that would cling to the surface of the boat.
They’re the food source for algae, and other microscopic organisms at the base of the food chain.
So the weed and shells have nothing to feed on, and never take hold and grow in the first place.
No food, no growth, clean boat, lower CO2.
It’s a tantalisingly simple formula, but one which, the company’s environment director Darren Jones says, their technology has tried and tested for years on boats.
It just needs governments and regulators to sit up and take notice.
Especially when it comes to improving the impact of shipping and deliveries, says Mr Jones.
‘Carbon savings are enormous’
“If you’re interested in, ‘is the van that delivers to my house that last few miles electric?’, you should actually be more interested in how clean was the ship, because that is where you’re going to make a saving in carbon. That’s where you’re going to make a difference.
“The carbon savings are enormous. If you imagine a container ship, if it’s got no fouling, it would be the equivalent of switching tens of thousands of people from their diesel car to an electric car.”
This all matters because of the scale of the industry. The shipping industry contributes between 2.5% and 3% of annual global carbon emissions. Some 940 million tonnes of carbon dioxide a year.
And, as we’ve seen with disruption in recent months, we rely on shipping for so much of our trade. It’s integral to our globalised economy.
Until there are zero-carbon alternatives to fuel our tankers, reducing emissions by other means is vital, says Mr Jones.
“If we could reduce the carbon footprint of the biofouling, just reduce that drag, it would be the equivalent of having the entire German economy zero carbon.
“We could do that overnight. The technology exists today. It’s not about invention, it’s about adoption. And the beauty is, it saves the shipping organisations money.”
And it could help with the longer-terms transition to net zero in the shipping industry as well, Mr Jones adds.
By making ships more energy efficient, greener fuels become viable.
‘This is a game-changer’
“In the longer picture, as we get away from fossil fuels, we need to move to alternative technologies to propel our vessels, be that electric, hydrogen, whatever.
“Now, energy density is difficult. How do you get across the Atlantic on hydrogen, because it hasn’t got the energy density of fossil fuels? If you’ve got less drag, if you’re using 50% less fuel, you can go 50% further.
“So this is a game-changer. It’s not just for today, this is a technology for tomorrow.”
In the fight against global warming and reducing carbon emissions, it’s often the little things that make a big difference.
Small lifestyle changes, such as cutting down on eating meat, adding insulation to your home, or perhaps just keeping your boat clean.