Kelp, a kind of seaweed, can be used in biofuels that one day could power ships and aircraft. That would sharply reduce the use of gas and oil, which emit greenhouse gases that lead to global warming. Proponents also argue it would allow the United States to be less susceptible to energy crunches like the one caused by the war with Iran. However, energy companies are hesitant to invest in large-scale aquaculture projects without demonstrated demand, while farmers are reluctant to scale up without a guaranteed buyer. It’s a circular problem that has slowed industry development. Still, marine scientists, such as those at the Woods Hole Oceanographic Institution in Massachusetts, are confident that the advantages of kelp for fuel will eventually lead to market growth.