I think I wondered if this would work

 

When Sargassum first started to show up in much greater amounts than had been historically observed, washing up on beaches and offending tourists (particularly their noses), I wondered if all that biomass could be processed for biofuel.

I guess I wasn't the only one.

How the Caribbean could turn a plague of seaweed into fuel and fertilizer

"Removing seaweed from beaches and carting it to the dump costs countries millions of dollars a year and takes up dwindling space in landfills. But officials in Grenada, an island nation of more than 100,000 people at the far end of the Caribbean archipelago, say they have a better idea: Harvest the sargassum before it hits the beaches and turn it into a renewable source of fuel, fertilizer and other products.

“We shouldn’t just see sargassum as a menace, but as an opportunity,” said Jerry Enoe, Grenada’s special envoy for oceans.

In October, Grenada hosted a sargassum conference among Caribbean nations and the European Union, which has pledged to support Caribbean efforts to turn its climate-change-fueled problem into a green industry. At the conference, Grenadian Prime Minister Dickon Mitchell vowed that his country would transform 10,000 tons of sargassum into useful products by 2026."

Here's another article about this idea.

Researchers convert washed-up seaweed into biofuels and fertiliser

There's certainly enough of it.