New explainer: The race to turn sargassum into value
How Dr Mar Fernández-Méndez and MacroCarbon are leading the charge to transform the Caribbean's seaweed crisis into carbon-negative aviation fuel.
We don’t often find ourselves geeking out about seaweed — but this one was worth it.
Every year, millions of tonnes of sargassum seaweed drift from West Africa to the Caribbean, smothering beaches, releasing methane, and disrupting local economies. For most, it’s a coastal nightmare. For Dr Mar Fernández-Méndez, it’s a new kind of fuel story.
As the co-founder of MacroCarbon — and guest of last week’s Signal episode — Fernández-Méndez is leading a bold effort to turn this floating menace into carbon-negative sustainable aviation fuel (SAF).
Her process turns the invasive sargassum into hydrogen-rich SAF, capturing carbon as it grows and cleaning the ocean in the process. It’s a rare “two-for-one” climate innovation — tackling both marine and atmospheric challenges.
We’ve just published a free explainer report that unpacks the science, economics, and significance of this fast-moving field.
Here’s what you’ll find inside:
How a drifting seaweed bloom became a $300M-a-year environmental emergency for the Caribbean;
Lessons from the microalgae boom — and why MacroCarbon’s macroalgae model is different;
How sargassum can produce four revenue streams — bio-stimulants, biochar, carbon black, and SAF;
How carbon pricing and EU mandates make ocean-based SAF increasingly competitive;
MacroCarbon’s carbon-negative fuel vision that enhances marine biodiversity instead of harming it.
If you missed last week’s Signal episode with Dr Fernández-Méndez, you can listen here before diving into the full story:
