The Troubles of the Ocean Cleanup Project

Boyan Slat
Boyan Slat pictured in 2015.

The Ocean Cleanup is a Dutch environmental organisation which aims to create new technology which can remove plastic pollution from the world’s seas and oceans. Founded in 2013, the organisation has received high levels of publicity and backing from celebrities and prominent business people and received millions of dollars in funding. Bold initial claims about the technology were made and it was claimed that the Ocean Cleanup would potentially be able to remove millions of tons of plastic pollution from the oceans (1) while being powered by renewable sources such as wind, wave and solar power (1). Indeed, at the outset, the project talked of removing the majority of plastic from the Great Pacific Garbage Patch within a decade (1).

However, many of these initial aims have not been met and the Ocean Cleanup project has significantly changed both its claims on how much plastic it can remove from the seas and oceans, and drastically scaled back the innovative technology it will use to collect the waste. This has led to high levels of criticism from the scientific community and from conservationists who believe that the money spent on Ocean Cleanup could have been used more effectively on other projects.


The Ocean Cleanup project was founded by Dutchman Boyan Slat when he was eighteen years old. He was inspired to form the organisation when he was on a family holiday in Greece in 2011 and found more plastic than fish when diving in the ocean. Two years later he founded the Ocean Cleanup and by 2015 had raised over $2.2 million (£1.7 million) to fund the project (2), with a total of $35 million (£26.8 million) being raised by 2021 (3). Celebrities and prominent business people such as billionaire internet entrepreneur Marc Benioff and PayPal co-founder Peter Thiel donated money to Ocean Cleanup and publicly backed the project.

The initial aims of the Ocean Cleanup were extremely ambitious and focused on cleaning up the Great Pacific Garbage Patch – a concentration of marine rubbish covering hundreds of thousands of square miles which is trapped in the middle of the Pacific Ocean by currents and gyres. Initial concepts of the system envisioned vast booms extending for miles across the sea. Screens would hang underneath these booms and collect the floating marine pollution and rubbish which flowed into them. A conveyor belt system would then transport the rubbish into sleek, yacht-like central units where automated conveyer belts would move the rubbish into storage towers.

System 001
The inital plans for the Ocean Cleanup, named System 001, proposed huge 60-mile long booms which would be powered by renewable energy, connected to satellites and passively collect plastic waste.

Satellite pods would allow the exact location of the booms to be monitored from Ocean Cleanup’s headquarters in Rotterdam and also allow approaching vessels to see the location of the booms to avoid collisions. Further sensors would monitor weather and sea conditions and would constantly feedback information on how the boom was performing and the amount of plastic which was being collected. A camera system would also allow 360-degree monitoring of the boom with images beamed back to Ocean Cleanup in real-time, and lanterns would light up the booms for added visibility. The scale of the device was vast, with Slat envisioning the booms being 100 km (60 miles) long (2). This design won multiple awards, including Design of the Year from the London Design Museum (4).

Prototypes and Testing

Scale models and smaller sections of booms were manufactured and a 100-metre (328 ft) prototype was tested in the North Sea in 2016 (5). This version used inflatable rubber booms which were fitted with sensors to monitor the impact of the waves and tides. Slat stated that the aim of the North Sea tests was not to collect plastic and rubbish from the sea but to assess how well the booms coped with the sea conditions. He added that the tests were “a historic day on the path toward clean oceans” (5). In late August 2016 Slate wrote an update on the tests on the official Ocean Cleanup website. He said that after almost two months at sea the device had been subject to harsh conditions including large waves and winds of 45 knots (51 mph). Despite this the boom came out in “reasonably good condition” and Slat said his team were “confident multi-year survivability is an achievable design goal” (6).

Ocean Boom
Booms were tested in 2016, with the design being significantly changed by 2018.

However, between 2017 and 2018 the design was to undergo drastic changes, with much of the ground-breaking technology being stripped from the plans. The idea of a 100km/60-mile boom which was anchored to the seabed was dropped, as was the idea of a conveyor belt system which transported rubbish to a central tower. Instead, a fleet of much smaller U-shaped booms was designed. These were not attached to the seabed but were instead free-floating and would passively collect debris which flowed into them as they moved across the sea (7). These booms would not have a conveyor belt system to move the waste and would instead need to be periodically emptied by a support vessel. This was billed as the “final design” of “the world’s first ocean cleanup system” on the organisation’s website (7).

In July 2018 the two 60-metre (196 ft) sections of the boom, now named System 001 “Wilson”, were tested in San Francisco Bay. The Ocean Cleanup’s official website reported that the “unit behaved very well. It endured a severe storm and withstood the forces of the ocean during this time.” In September of 2018 System 001 was towed 240 nautical miles (445 km) out into the Pacific Ocean for further tests (8).

Criticism Begins

Ocean Plastic Pollution
Ocean cleanup has struggled to collect plastic pollution.

It was at this time websites such as Business Insider and Popular Mechanics began reporting that even though Ocean Cleanup had significantly reduced the size of the booms and removed the complicated conveyor belt system, this new version of their booms was still failing to remove plastic from the ocean. Both websites stated that the booms may be moving through the sea too slowly, allowing debris to flow out, while vibrations at the edges of the booms may also prevent plastic from entering the booms and Ocean Cleanup’s engineers could not identify exactly why this was happening (9), (10). In the final few days of 2018, it was also reported that System 001 had not been robust enough to withstand the conditions of the Pacific Ocean and had broken apart while being tested (11).

This led to serious questions being asked about the feasibility of the entire project. In January 2019 the website the Verge published a special report entitled “Why So Many of Us Wanted to Believe in an Ocean Cleanup System that just Broke Apart.” The report’s author, the Verge’s science correspondent Rachel Becker, pointed out that coverage of the project had been continuously positive and upbeat, even when prototypes had failed and targets had not been reached.

Becker pointed out that the Huffington Post had referred to the Ocean Cleanup as “miracle ocean cleaning tech” before it had even proved that it worked, and Time magazine named the initial design of the booms as one of the best inventions of 2015, despite the absence of a workable prototype no evidence that it could effectively collect plastic pollution. Becker also added that scientists who have been claiming that Slat’s plans were unrealistic since 2014 have been ignored (12).

More significant criticisms about the entire basis of the Ocean Cleanup project were also made during this time. Alexander Bond, a senior curator at the Natural History Museum was quoted in the Verge article as saying that with 350 million tons of plastic being produced across the world every year plastic was “literally everywhere” saying it was found:

“At the bottom of the Mariana Trench, the deepest place in the ocean. It’s in the sea floor under the Arctic ice caps, we see it on the most remote islands” (12).

Because of the sheer amount of plastic waste which flowed into the oceans it made much more sense to spend resources stopping the pollution at its source, rather than try to collect a small portion of what was already in the seas and oceans while more and more continued to flow in. Bond said that much of Ocean Cleanup’s appeal was that it made plastic pollution seem like an issue people didn’t have to deal with, telling Verge “it moves the proposed solution to ‘out there,’ where the trash is, rather than into our own lives, where the trash is being generated” (12).

First Plastic Collected at Sea and New Interceptor™ System Developed

In October 2019 the Ocean Cleanup project successfully collected its first plastic when a 600 metre (1968 ft) free-floating boom was deployed in the Pacific Ocean at the Great Pacific Garbage Patch. The Guardian reported that the new design of the boom incorporated an underwater parachute anchor which slowed the boom down and allowed it to passively collect plastic. Boyan Slat was quoted in the paper as saying:

“We are now catching plastics … After beginning this journey seven years ago, this first year of testing in the unforgivable environment of the high seas strongly indicates that our vision is attainable and that the beginning of our mission to rid the ocean of plastic garbage, which has accumulated for decades, is within our sights. We now have a self-contained system in the Great Pacific Garbage Patch that is using the natural forces of the ocean to passively catch and concentrate plastics … This now gives us sufficient confidence in the general concept to keep going on this project” (13).

Slat also said that he believed that the Ocean Cleanup project would become financially self-sustaining as they would be able to sell products made out of the waste plastic they recovered, telling the Guardian that when they had a “full-scale fleet” of plastic-collecting booms they would be able to “cover the operational cost of the clean-up operation using the plastic harvested” (13).

In late 2019 Slat announced a new invention named the Interceptor™. This was described as the “world’s first scalable solution for preventing river debris from entering the ocean” (14). Backed with funding from Coca Cola, the Interceptor™ resembles a catamaran-style boat which uses a barrier placed in the river to guide plastic and other forms of floating waste into the Interceptor™. A system of conveyor belts then sorts the waste into dumpsters which can contain up to fifty cubic metres before they need to be emptied. Ocean Cleanup say that the Interceptor™ can remove up to 50,000kg (110,000 lbs) of rubbish from rivers each day and can operate autonomously 24-hours a day as it is solar powered (15). As of April 2022, the Ocean Cleanup website states that Interceptors™ are operating in Indonesia, Malaysia and the Dominican Republic, and there are plans to Vietnam, Thailand, Jamaica and the USA (15). With 80 per cent of oceanic plastic pollution coming from a relatively small proportion of the world’s rivers, it was believed that the Interceptor™ system will be an effective way of stopping floating pollution before it reaches the open oceans.

New System Developed but Criticism Intensifies

While the Interceptor™ may prove to be a success, Slat was not giving up on a way of cleaning up the Great Pacific Garbage Patch. In mid-2021 yet another design was unveiled. Named System 002 “Jenny” this consisted of a U-shaped boom which was 520 metres (1,706 feet) wide, but this time it used “active propulsion” (16), essentially meaning it was pulled through the sea by two ships. Ocean Cleanup claimed that this was, in fact, better than the passive systems they had spent years trying to develop, as it meant that they could “steer the systems towards areas with high concentrations of plastic” (16). The fact that the fleet of multiple, smaller, free-floating booms had been referred to as the “final design” in 2018 was not referenced, although the webpage stating this is still available to view on the Ocean Cleanup’s official website as of April 2022.

Ocean Cleanup Ship
Fossil fuel-powered Maersk tender ships are used to provide “active propulsion” for the current incarnation of Ocean Cleanup’s plastic-removing technology.

This new system was heavily criticised when details of it emerged. The Ocean Cleanup had regressed from a huge 60-mile long satellite-connected boom powered by renewable energy to a net being pulled through the sea by two boats. In an article on the science and technology website Gizmodo, Dr Miriam Goldstein, the director of ocean policy at the Centre for American Progress, said that System 002 was effectively a trawl and Ocean Cleanup had spent “many tens of millions of dollars to [re]invent fishing” (17). The same article also criticised the new system for being towed by two diesel-powered Maersk tender vessels which would have a “hefty carbon footprint,” although Ocean Cleanup said that they would pay to offset the carbon emitted by the ships (17). The Gizmodo article also stated that System 002 could have a major issue with bycatch. Tens of thousands of small sea creatures such as mid-water crustaceans, small fish, jellyfish and squid potentially being caught even when the system was used at its slowest speed (17).

Furthermore, quotes from a BBC interview with Boyan Slat came back to haunt him. Speaking in 2014 he said:

“Most people have this image of an island of trash that you can almost walk on, but that’s not what it’s like … It stretches for millions of square kilometres – if you went there to try and clean up by ship it would take thousands of years. Not only that, it would be very costly in terms of both money and energy, and fish would be accidentally caught in the nets” (18).

Clearly, using nets to remove plastic pollution from the ocean was never the aim of Slat and the Ocean Cleanup, and the change to now claim that an active ship-and-net based system was somehow better and more effective than the passive system entirely powered by renewable energy they had spent so long developing was seen as disingenuous by critics of the project.

In 2021 the underwhelming performance of System 002 continued. A test in Canadian waters revealed that after being at sea for 120 hours 8.2 tonnes (18,000 lbs) of rubbish had been collected. An article on the Reuters website said that crew members were “thrilled” with the results of this test, despite this being “less than a garbage truck’s standard haul.” Ocean Cleanup said that they wanted to deploy 10 to 15 System 002s around the clock to remove 15,000 to 20,000 tonnes of debris a year and clear up the Great Pacific Garbage patch (19). However, the Reuters article pointed out that this would potentially cost millions of dollars, generate large amounts of carbon and would only remove a tiny fraction of the estimated eleven million tons of plastic entering the oceans each year (19).

The Reuters article also revealed that while some of the plastic which had been recovered from the sea had been recycled to make products to sell and fund the project (such as sunglasses which retailed for $200 (£155), but Ocean Cleanup admitted that other plastic they had collected may have to be incinerated (19). It was also disclosed that the Ocean Cleanup project had raised over $100 million (£76.7 million) since the project began (20).

Fakery Accusations

In early 2022 Ocean Cleanup received more negative publicity when the organisation was accused of faking pictures of rubbish being removed from the sea. The organisation’s verified Twitter account tweeted a video of a net full of plastic waste being removed from the sea and dumped on the deck of one of the Maersk tender ships. Many marine biologists and scientists were quick to allege that the plastic looked remarkably clean, especially as it may have been in the sea for up to thirty years. Dr David Shiffman, a marine biologist at Arizona State University told Newsweek that:

“The imagery they showed is just not at all what it would look like if one were to truly drag a big net through the ocean and scoop up plastic that had been floating there for years … It’s too brightly coloured, nothing is growing on it, and they didn’t catch anything but plastic” (21).

Trevor Branch, associate professor at the School of Aquatic and Fishery Sciences at the University of Washington, also speaking to Newsweek, said:

“The plastic they picked up, most of which they say is ten to thirty years old, is so clean and free of the organisms that usually grow very quickly on anything in the ocean … although I am not an expert in biofouling, others had similar questions” (21).

Ocean Cleanup strongly refuted the allegations of faking footage and said that the plastic was recovered from an area of the ocean which was low in nutrients which explained why there was little algal growth, and as much of the plastic stuck out of the water the ultraviolet sunlight prevented organisms from growing on the plastic. This did not convince some people such as oceanographer Clark Richards, who tweeted “I call bullshit on this stunt — this is likely a staged video” (22).

The Future of Ocean Cleanup

At the time of writing (April 2022) the Ocean Cleanup project continues to divide opinion. The project has had successes at stopping plastic pollution from reaching the sea with its Interceptor™ devices, but the organisation’s attempts to clean up the Great Pacific Garbage Patch appear to have failed. In retrospect, its plans for renewable-powered sixty-mile long floating booms which removed debris from the sea and then store it away using conveyor belts were wildly unrealistic, and even scaled-down attempts to passively collect plastic pollution have ended in failure. The Ocean Cleanup has now been reduced to using fossil fuel-powered ships to tow nets through the sea to collect plastic – something which could have been done at the outset and saved tens of millions of dollars. Furthermore, Ocean Cleanup has never fully engaged with the criticisms which have been levelled at the organisation or admitted that the regression from a hi-tech boom system to a towed net represents a failure of its initial aims. Instead, a relentlessly positive and upbeat picture of what the project can achieve has been presented at all times, even though the whole project is likely to only achieve a fraction of the success it initially promised.

Mark Rober
Mark Rober, the hugely popular engineer and YouTuber, helped raise $30 which will be donated to Ocean Cleanup to develop the Interceptor™ technology to remove pollution from rivers.

Despite the criticisms and the issues, the organisation has faced, the Ocean Cleanup project remains popular and well supported. In October 2021 Boyan Slat announced that he was teaming up with the hugely popular YouTubers Mark Rober and MrBeast (who between them have over 100 million subscribers on the platform). The trio would work on a new campaign called #teamseas which aimed to get popular YouTubers and their fans to raise $30 million (£23 million) by January 2022. The money would then be “donated to the Ocean Cleanup will be put into the build, deployment, and operations of our Interceptor™ technology to prevent pollution and debris from entering the oceans via rivers” (23). The campaign was successful with 27-year-old American technology entrepreneur Austin Russell making a late $4 million (£3 million) donation to get the campaign over its $30 million target (24). As of April 2022, major companies such as the Danish shipping company Maersk, Coca-Cola, Deloitte and KLM are all listed as partners of the Ocean Cleanup project (25).

While Boyan Slat and the Ocean Cleanup retain popularity and goodwill, it remains to be seen if they will admit that their initial aims of cleaning up the Great Pacific Garbage Patch were simply too ambitious and unrealistic to ever have been achieved.


1. Could a Teenager Save the World’s Oceans?, Daily Mail, 9th September 2013.
2. A Sea of Plastic,, 26th September 2016.
3. Scooping Plastic Out of the Ocean Is a Losing Game, Hakai Magazine, 21st September 2021.
4. 2015 Design of the Year winners announced in London,, 30th August 2016.
5. Boyan Slat’s Ocean Cleanup Project Launches Historic First Prototype at Sea, Ecowatch, 23rd June 2016.
6. An Update from the  North Sea, Ocean Cleanup Website, 31st August 2016.
7. The Final Design of the World’s First Cleanup System, Ocean Cleanup Website, 21st July 2018.
8. The World’s First Ocean Cleanup System Launched from San Francisco, Ocean Cleanup Website, 8th September 2018.
9. An Ambitious Project to Clean Up the Ocean’s Garbage Patch Isn’t Working, Popular Mechanics, 10th December 2018.
10. The Massive Ocean Cleanup Device Invented by a 24-year-old is Running into Problems in the Great Pacific Garbage Patch, Business Insider, 6th December 2018.
11. Ocean Cleanup Device Breaks Down, Well Before Ridding Pacific of plastics, NBC News, 4th January 2018.
12. Why So Many of Us Wanted to Believe in an Ocean Cleanup System That Just Broke, The Verge, 9th January 2019.
13. Ocean Cleanup Device Successfully Collects Plastic for First Time, The Guardian, 3rd October 2019.
14. What is the Interceptor™?, Ocean Cleanup Website, Undated.
15. How Much Waste can the Interceptor Original™ extract? Ocean Cleanup Website, Undated.
16. FAQ, Ocean Cleanup Website, Undated.
17. The Dream of Scooping Plastic From the Ocean Is Still Alive – and Problematic, Gizmodo, 19th October 2021.
18. The Dutch Boy Mopping up a Sea of Plastic, BBC News, 17th October 2014.
19. Ocean Cleanup Struggles to Fulfil Promise to Scoop up Plastic at Sea,, 16th September 2016.
20. Oops, Cleaning the Great Pacific Garbage Patch was Probably a Bad Idea, Vox, 4th March 2022.
21. Ocean Cleanup Accused of Staging Removal After Plastic Looked Too Clean, Newsweek, 16th February 2022.
22. – Clark Richards PhD
23. The Ocean Cleanup and Ocean Conservancy Team Up with MrBeast and Mark Rober in #Teamseas Fundraising Campaign, Ocean Cleanup Website, 29th October 2019.
24. – MrBeast
25. Thanks to Our Partners We Can Clean the Oceans, Ocean Cleanup Website, Undated.