As the production of biofuel continues to increase, so does the need for sustainable feedstocks. Corn, canola, and sugarcane have all been used to produce biofuels, but the problem is that these feedstocks require land to grow on as well as a lot of resources such as water and fertilizers.
Kelp on the other hand doesn’t need any of that. Growing naturally within the marine environment, kelp is one of the fastest-growing plants in the world and provides a habitat for sea creatures. That said, raising the plant in controlled aquaculture settings raises a few challenges. For instance, the plant needs to be fixed to a substrate within sun-drenched waters to really thrive, but these parts of the ocean don’t offer the same abundance of nutrients found in deeper waters.
To get around this issue and help grow faster, a team of researchers from The University of Southern California came up with a novel contraption to get the best of both the nutrient-rich deep sea and the sun-drenched shallow sea. This machine is called the kelp elevator, and it raises the kelp up to the sunny surface during the daytime and lowers it to depths of around 260 ft (80 m) at night, allowing the kelp to soak up vital nutrients like nitrate and phosphate.
With the kelp elevator, which is made of fiberglass tubes and stainless steel cables, scientists were able to grow kelp off the coast of California much faster over the course of 100 days. In fact, the scientists produced four times the biomass of regular kelp using the kelp elevator.
“The good news is the farm system can be assembled from off-the-shelf products without new technology,” said Brian Wilcox, co-founder and chief engineer of company Marine BioEnergy, which came up with the elevator. “Once implemented, depth-cycling farms could lead to a new way to produce affordable, carbon-neutral fuel year-round.”