GrabCAD member Boyan Slat is a 19 year-old engineer from the Netherlands who is determined to change the world. He has invented a method to clean the ocean from plastic debris and started a company called The Ocean Cleanup. We interviewed Boyan about his impressive undertaking.
Boyan's concept for The Ocean Cleanup uses the natural ocean currents and winds to passively transport plastic towards a collection platform. Instead of using nets and vessels to remove plastic from the water, floating barriers make entanglement of sea life impossible. Boyan estimates that deploying this system for ten years would remove almost half of the plastic within the Great Pacific Garbage Patch.
What is your background? Are you an engineer?
It depends on which definition you use. In 2012 I started studying Aerospace Engineering, but decided to pause my study after 6 months to focus all my time on developing my concept. Besides leading a team of 100 people that performed the feasibility study, I have primarily been involved with the engineering side of things.
How is The Ocean Cleanup important to the world?
Every year we produce about 300 million tons of plastic, a portion of which enters and accumulates in the oceans. Due to large offshore currents, plastic concentrates in vast areas called gyres, of which the Great Pacific Garbage Patch between Hawaii and California is the best- known example. The damage to sea life is staggering: at least one million seabirds, and hundreds of thousands of marine mammals die each year due to the pollution. Even worse, the survival of many species, like the Hawaiian Monk Seal and Loggerhead Turtle, is directly jeopardized by plastic debris.
The Ocean Cleanup utilizes long floating barriers which - being at an an angle - capture and concentrate the plastic, making mechanical extraction possible. One of the main advantages of a passive cleanup concept is that it is scalable. Using the natural circulation period of the North Pacific Subtropical Gyre, cleanup duration could be reduced to just 5 years.
Another benefit of a passive collection approach is that operational expenses can be very low, making the cleanup more viable. Furthermore, converting the extracted plastic into either energy, oil or new materials could partly cover execution costs. Because no nets would be used, a passive cleanup may well be harmless to the marine ecosystem and could potentially catch particles that are much smaller than what nets could capture.
How did you come up with the cleaning system concept?
I was 16 years old, and I was diving in Greece, and suddenly I realized I came across more plastic bags than fish. For a high school science project I dedicated half a year to understanding the problem itself, and why it’s so difficult to clean up. I’d always been interested in engineering, so I came up with a concept of how I thought we could feasibly clean the ocean garbage patches.
What are the biggest engineering challenges?
The most challenging part of the engineering process was the design of the long floating barriers. They have to survive extreme conditions, as well as follow waves. Simulations revealed that these ‘booms’ should be longer than 1400 m, but would not follow the waves because of the tension in the cable that runs through it.
So we decided to suspend the tension cable at a depth of 30 m, and connect the cable to the barrier at 60 m-intervals. This prevents the build-up of tension in the barrier, but more significantly it enabled the boom to sway with the waves, reducing loads. Scale model tests even indicated a reduction of 60% in dynamic force.
How much has the concept changed during the feasibility study and research?
The basic principle hasn’t changed, though some details have changed though. For example, the platform design has now been improved, based on a spar platform. The most significant result of the study was that with only $30m per year, using a single system, deployed over 10 years, almost half the plastic from the Great Pacific Garbage Patch can be removed.
What's next for your team?
We are currently making preparations for the second phase of the project; the pilot phase. To help fund this major next step, we have now launched a crowdfunding campaign, through which we hope to raise $2 million in 100 days. It is now live on theoceancleanup.com.
To address the remaining uncertainties identified in the feasibility study, a second phase of the project is proposed to prepare for implementation. In this phase, The Ocean Cleanup would develop a series of up-scaling tests, working towards a large-scale operational pilot in 3 to 4 years. The scale of these tests will likely range from ~10m at the scale model test (1:1000) to ~10km at the large-scale operational test (1:10). Besides assessing new engineering results in a real world environment, these tests also serve to uncover any unforeseen interactions between the structure and the environment, while allowing for the practicing of operational procedures.
And although a cleanup will have a profound effect, it is just part of the solution. We also need to close the tap, to prevent any more plastic from reaching the oceans in the first place.
PS: As a side-note: the plastic bottles that can be seen floating in the artist’s impressions actually originate from GradCAD!
Thank you Boyan for this interview and good luck with the crowdfunding campaign!
Watch his TED Talk about the project.