Can The Ocean Cleanup Eliminate the Great Pacific Garbage Patch?
Converting Plastics to Energy: The End of the Line
January 2, 2019
On September 8, the Danish offshore tugboat Maersk Launcher left the port of San Francisco, towing a 2000-foot-long floating tube attached to a 10-foot screen.
It’s destination? The Great Pacific Garbage Patch (GPGP), about 1400 nautical miles off the coast of the U.S.
It’s purpose? Begin to clean up the largest accumulation of ocean plastic in the world.
A Teenager’s Dream Come True
Dutch inventor Boyan Slat was 16 years old, diving off the coast of Greece, when he was surprised to see more plastic than fish down there. “Why don’t we just clean it up?” he kept thinking.
Two years later, he finally got a chance to do something.
In 2013 Slat founded a non-profit technology firm called The Ocean Cleanup. Crowdfunding provided the initial $90,000 in start-up capital, as well as a subsequent $2.2 million.
Over a two-year period, the company conducted six expeditions to the North Atlantic to measure the vertical distribution of ocean plastic. Three expeditions to the GPGP followed.
A mega expedition of 30 vessels in 2015 discovered that the plastic concentration in the GPGP was much greater than previously estimated. They also learned that most of the plastic was large debris, such as abandoned fishing gear.
After three more years of testing, including a North Sea prototype, the first stage of the GPGP cleanup (dubbed System 001) was finally deployed from San Francisco last September. On October 16, it reached its destination and began its massive task.
You can follow the progress of System 001 on Twitter or by clicking here.
How It Works
The Ocean Cleanup team consists of more than 80 engineers, researchers, scientists and computational modelers. But the principle behind The Ocean Cleanup is relatively simple: Use the ocean’s own currents to passively catch and concentrate plastic debris.
Here’s how the system works:
Wind and ocean currents move the U-shaped floater system slightly faster than the ocean plastic.- As plastic accumulates in the center of the U, the system acts like a giant Pac-Man, skimming the ocean surface.
- Every few months, a garbage vessel extracts the collected plastic.
- The collected plastic is sent to land-based recycling centers. From there, it’s refashioned into consumer goods and sold. Revenues are then used to help fund ocean cleanup in other areas of the world.
The company’s long-term goal is to deploy 60 systems by the year 2020. At that rate, Slat estimates that 50% of the entire GPGP could be cleaned up in five years.
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Protecting Marine Life
But what about marine life? Is it at all affected by Slat’s floating systems? Apparently not. In fact, the company outlines four ways in which The Ocean Cleanup system is designed to protect sea life:
- The systems move through the ocean at extremely low speeds, allowing creatures to swim away.
- The screen attached to the floater is impenetrable, so the ocean current flows beneath the screen. Any organisms that can’t actively move are guided below the screen. (Floating plastic remains inside the system.)
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The screen is not a net, so sea life cannot become entangled.
- Crew members are present to check for marine life whenever plastic is removed from the water.
The Nature of the Beast
One of the more surprising findings of the company’s earlier expeditions has been the nature of the plastic within the GPGP. Specifically, that three-quarters of it is large — between two and 20 inches in size. (While microplastics comprise 94 percent of plastic in the patch, that only amounts to eight percent of the total tonnage.)
In fact, fishing nets account for 46% of the mass in the GPGP. The majority of the rest is other fishing industry “ghost gear” (ropes, oyster spacers, eel traps, crates, and baskets).
Not only is the ghost gear a serious hazard for marine life, but it can also break down into smaller pieces and microplastics within the GPGP. Once that happens, they’re very difficult to remove and are often mistaken for food by marine animals.
To Boyen Slat, the next few decades will be crucial to ensuring that these large pieces of plastic don’t become microplastics.
“If we don’t get it out, the amount of microplastics can be tenfold or 100-fold. It’s this problem that’s waiting out there to magnify many times unless we can take it out.”
In the following video, Mr. Slat further explains the details of his entire project and the science behind it:
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