Produced by Maija Palmer, Filmed by James Sandy, edited by Oliver McGuirk
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Much work is being done to find more sustainable sources of energy for the world's growing population. But one of the answers could come from the ocean - using seaweed as biofuel.
It grows so quickly, much, much quicker than land plants. It has a higher photosynthetic capability. It can sequester carbon dioxide out of the atmosphere much better and quicker than land plants. So there's kind of lots of potential benefits of using seaweed as a feedstock.
The SeaGas project in the northeast of the United Kingdom is exploring how best to turn seaweed into a biogas.
You saw the seaweed go in off the boat. And this is what it looks like.
It is a very sweet smell that's coming off this now.
It is, actually. It's actually quite pleasant. So Maria's going to take the seaweed and going to feed it into the hopper, which is the front end of our AD process, our anaerobic digestion. That will feed through the particular shredder, macerator and then into the feed tank to get it into the right consistency and the right strength for the process.
Oh wow. So what are these?
They're our five-litre So we're able here to test the different seaweed feedstocks and different blends of seaweed and food waste together.
I think it's been very difficult to use seaweed in the west on any kind of commercial scale. Although the process works fine, the ensiling has worked very well, the anaerobic digestion has worked very well, we see very good levels of methane production - every bit as good as energy crops from land, but what really skews the whole economics at the moment is the seaweed farming itself. That's a very expensive process.
Off the coast of Catalina near Los Angeles, a start-up called Marine BioEnergy together with the University of Southern California's Wrigley Institute is designing a robot submarine that could maximise the growth of kelp.
Kelp is attached to long lines pulled by the drone up near the ocean surface during the day to get as much sunlight as possible, and then submerge to the deeper nutrient-rich parts of the ocean at night. When the kelp is ready to be harvested, it can be pulled to a nearby ship and processed to turn it into the equivalent of crude oil.
It would still require a huge kelp farm - something the size of the state of Utah - to supply 10% of the energy needs of the United States, says Bob Wilcox, who leads the project.
A research collaboration between ExxonMobil and Synthetic Genomics has used genetic engineering to increase the oil content of algae from 20% to 40%. This is a level at which seaweed starts to become a useful substitute for petroleum-based fuels.
People have been investigating algal biofuels since the 1970s without a huge amount of success. But these more recent projects suggests that we could be getting closer to using these fast-growing plants as a clean, green source of energy. Maija Palmer, Financial Times, Redcar.