Stock image of seaweed removed from the ocean. iStock
Rum and Sargassum, a startup in Barbados in the Caribbean islands, is turning rum waste from distilleries and seaweed washed off onto the shores to produce bio-compressed natural gas to fuel cars.
The startup was founded by mechanical engineer Legena Henry and her data scientist husband to help the country continue to attract tourists while also meeting its net zero goals.
Sargassum, or seaweed, has been invading Caribbean beaches for over a decade. The warming oceans and increased marine pollution have propelled the weed growth in the Sargasso Sea, which gets washed up on the pristine beaches in the Caribbean.
Once it reaches land, seaweed begins to rot. While mounds of seaweed and rotting smells are unpleasant for tourists, they are also a health risk for marine animals. Resorts spend millions of dollars every year to remove seaweed from the beaches, but Henry’s startup could turn this adversity into a win-win situation.
An idea that worked
Barbados has set an ambitious goal to become fossil-fuel-free by the end of this decade. However, Henry, a researcher and lecturer at the University of West Indies (UWI), believes this will have a massive economic impact since electric vehicles (EVs) are too expensive for the country’s common man.
Existing internal combustion engine vehicles can be retrofitted with a kit in about four hours and run on gas. The cost of the kit is a fraction of that of an EV. So, Henry was working to replicate Brazil’s success in using sugarcane to create biofuel that could power cars.
But while working on this project, Henry and her student Brittney McKenzie encountered trucks being deployed to clear up sargassum and wondered if they could use this material instead.
Using seaweed from the beaches and rum distillery wastewater, another waste the islands have to contend with, Brittney set up small batches of reactors, and their preliminary results were promising.
Saving tourism without fossil fuels
Henry also hired another biologist to determine what combinations of sargassum and wastewater produced the highest levels of natural gas. Once the technology was perfected, the team filed a patent in 2019 and sought more funding to deploy it as an experiment.
They tested their biofuel in a Nissan Leaf and decided to float Rum and Sargassum next in 2021. The startup is now working to scale up its production to meet demand for its initial target of 2,000 customers.
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In the long term, the company plans to supply fuel to 100,000 fossil fuel-powered vehicles, about 75 percent of all vehicles in Barbados. This would prevent an estimated 14 million tons of CO2 from being released into the air while also reducing the cost of fuel by half for vehicle owners. This could help tourism continue even without using fossil fuels.
But scaling up isn’t that straightforward. Henry estimates that selling fuel to 300 taxis would cost the company $7.5 million, and a mix of debt financing from development banks and venture capital could help raise these funds.
If successful, the solution could be applied in many places where seaweed has been troublesome but could eventually become a boon.
This report contains information that first appeared in Nature and theBBC.
