Climate change: How barnacles and algae on ship hulls increase carbon emissions – and the little device that could change the game | Climate News


A small device that emits tiny vibrations from a ship’s hull is a “game changer” in the fight to make container ships more environmentally friendly, its developer has said.

When barnacles, weeds and mussels settle on the hulls of ships, they create drag – or resistance, which makes it harder for ships to move through the water.

This means they have to burn more fuel and emit more carbon dioxide (CO2).

As research associate Andrea Grech La Rosa says, “It’s like trying to wade through water with a lot of clothes pulling you back.”

He spends his time studying different ways to increase the efficiency of ships in the towing tank at University College London.

Andrea Grech La Rosa uses ship models to carry out her research

“Seaweed, barnacles, all of this is to the detriment of the hull because the once smooth hull is going to be rougher, it’s going to disrupt the flow. It’s direct drag working against the ship.

“So the less algae or barnacles you have on the hull, the better the fuel mileage.”

In fact, the International Maritime Organization – the UN’s governing body for shipping and the seas – estimates that a ship could burn 55% more fuel, with 55% higher emissions as a result, barnacles covering only 1% of its shell.

It shows the difference a few seashells make.

Even a layer of mud as thin as half a millimeter covering 50% of a ship’s hull surface could increase its greenhouse gas emissions by 20-25%.

It’s a problem which, according to Mr. Grech La Rosa, is made worse by the increase in consumer demand.

“We want ships to deliver our items at the same rate, not making bigger ships, the only alternative is to go faster. And that means having fuel-efficient ships is key to ensuring that our emission levels are low.”

Currently, the industry relies on antifouling paints, with agents that kill these organisms, but these biocides are toxic and can also release microplastics, thus impacting the environment.

And sooner or later the paint will fade and the ship will have to be taken out, cleaned and repainted.

The small speaker attaches to the hull and vibrates

Even pulling a small boat out of the water can cost thousands of pounds and risk spreading invasive species to the world’s oceans.

But Coventry-based Sonihull may have the answer. The company has developed what is effectively a small speaker that attaches to the hull of boats and vibrates.

The tiny vibrations, too weak to interfere with the boats sonar equipment, or even marine life, create tiny bubbles around the hull.

Container ships burn more fuel and emit more CO2 when they have barnacles and algae on their undersides
Container ships burn more fuel and emit more CO2 when they have barnacles and algae on their undersides

When these tiny bubbles implode, they destroy single-celled organisms that would cling to the surface of the boat.

They are the food source for algae and other microscopic organisms at the base of the food chain.

So weeds and shells have nothing to feed on and never settle and grow.

No food, no growth, clean boat, less CO2.

It’s a tantalizingly simple formula, but one that, according to the company’s environmental manager, Darren Jones, their technology has been proven for years on boats.

Governments and regulators just need to sit up and take notice.

Especially when it comes to improving the impact of shipping and delivery, says Jones.

“The carbon savings are huge”

“If you’re interested in, ‘is the van delivering to my house for the last few miles electric?’ you should actually be more interested in the cleanliness of the ship, because that’s where you’re going to save money. in carbon. This is where you will make the difference.

“The carbon savings are huge. If you imagine a container ship, if there is no fouling, it would be equivalent to switching tens of thousands of people from their diesel car to an electric car.”

Darren Jones says the device that emits vibrations has been proven for years
Darren Jones says the device that emits vibrations has been proven for years

This all matters due to the scale of the industry. The shipping industry contributes between 2.5% and 3% of annual global carbon emissions. Some 940 million tons of carbon dioxide per year.

And, as we have seen with the disruptions of recent months, we rely on shipping for much of our trade. It is an integral part of our globalized economy.

Until there are carbon-free alternatives to power our tankers, it is vital to reduce emissions in other ways, says Mr Jones.

“If we could reduce the carbon footprint of biofouling, just reduce that drag, that would be equivalent to having the entire German economy zero carbon.

“We could do it overnight. The technology exists today. It’s not about invention, it’s about adoption. And the beauty is that it allows transportation organizations to to save money.”

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It could also help with the longer-term transition to net zero in the shipping industry, Jones adds.

By making ships more energy efficient, greener fuels become viable.

“This is a game changer”

“Longer term, as we move away from fossil fuels, we need to move to alternative technologies to power our ships, whether electric, hydrogen, whatever.

“Now the energy density is difficult. How do you cross the Atlantic with hydrogen, because it doesn’t have the energy density of fossil fuels? If you have less drag, if you use 50% less fuel, you can go 50% further.

“So this is a game-changer. It’s not just for today, it’s 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, like reducing meat consumption, adding insulation to your home, or maybe just keeping your boat clean.

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