Researchers bet kelp could one day fuel ships, planes

Why kelp keeps drawing attention

Kelp has one of the cleanest climate-tech pitches in the biofuels world: it grows in the ocean, not on farmland, and it avoids the fresh water and pesticide demands that come with corn-based ethanol. That makes it especially appealing for heavy transport sectors like shipping and aviation, where batteries are harder to use at scale and where the search for lower-carbon liquid fuels is still urgent.

The appeal is real, but so are the limits. Kelp is not a substitute for petroleum today, and even biofuels still release pollutants when burned. The question is not whether seaweed sounds greener than oil or corn, but whether it can be produced, harvested, processed and certified at a cost and scale that matter to the energy system.

What researchers are actually doing in Woods Hole

At Woods Hole, Massachusetts, researchers are growing tiny seaweed cells called gametophytes inside a red-light chamber to help breed faster-growing kelp strains. That work is aimed at one of the field’s most basic bottlenecks: if kelp is ever going to become fuel feedstock, it must grow faster, more predictably and in quantities large enough to support industrial demand.

This is where the science moves from concept to engineering. Breeding better strains is only one piece of the puzzle. Researchers also need to solve how to turn marine biomass into a fuel that can move through existing supply chains, meet fuel specifications and compete with established petroleum products on cost.

Why the fuel market matters more than the lab story

The broader biofuels push is not happening in a vacuum. The U.S. Department of Energy says sustainable aviation fuel can have a smaller carbon footprint than conventional jet fuel, depending on the feedstock and production technology. The Federal Aviation Administration has its own research agenda centered on feedstock innovation, lifecycle emissions reduction and supply-chain analysis, which shows how seriously policymakers are treating novel pathways into aviation fuel.

That matters because kelp fuel would need to fit inside a real regulatory system. The U.S. Environmental Protection Agency’s Renewable Fuel Standard remains a central framework for renewable transportation fuels in the United States, so any kelp-derived pathway would have to clear policy, certification and accounting hurdles, not just technical ones. In other words, the market will not reward novelty alone. It will reward fuels that can be measured, verified and delivered at scale.

The commercial test case is still small

There is already early commercialization activity around kelp-derived fuel. The Department of Energy has documented a project in which Macro Oceans, Inc. is working with the National Renewable Energy Laboratory on a kelp-waste-to-ethanol pathway designed to support sustainable aviation fuel. DOE materials describe that effort as an attempt to move kelp-to-ethanol beyond the lab bench, which is an important distinction in a field full of optimistic presentations and very few industrial proofs.

The project matters because it is specific. It is not just a vague promise that seaweed could someday become energy. It is a test of whether waste biomass from kelp can be converted into ethanol, then used as an intermediate for catalytic conversion into SAF. That is the kind of stepwise industrial pathway that any future seaweed fuel must eventually survive.

The economics are still the biggest obstacle

A 2025 review in Frontiers found that marine biofuel production is constrained primarily by fuel cost and then by feedstock availability. That ordering is telling. The field is not yet bottlenecked first by chemistry or public enthusiasm. It is bottlenecked by whether the fuel can be produced cheaply enough and whether there is enough biomass to keep plants running consistently.

That is why the size of the resource matters so much. Maine is the largest producer of sea kelp in the United States, and it harvested almost one million pounds in 2022, more than 20 times the 2017 level. That is real growth, but it is still tiny compared with the enormous volumes required to fuel ships or aircraft. Kelp farming can expand, but the gap between regional aquaculture and global transport demand remains vast.

Even the environmental case has caveats. A 2024 life-cycle study of kelp aquaculture found that minimizing boat use is important for reducing emissions. That is a reminder that seaweed fuel is not automatically low-carbon at every step. Boats, harvesting equipment, processing energy and transport all shape the final carbon footprint, and those upstream costs can erode the climate benefit if they are not tightly managed.

A Rhode Island farmer shows what the market looks like now

The human face of this industry is still closer to food than fuel. Oliver Dixon, a shellfish farmer in Point Judith, Rhode Island, grows kelp to supplement his oyster business during the winter. He expects to harvest about 10,000 pounds, or 4,500 kilograms, of kelp, and most of it currently goes to local restaurants and seafood markets.

That is the clearest reality check in the story. The American kelp economy exists, but its center of gravity is not aviation fuel. It is local food, shellfish farms and niche markets. Turning that same crop into a transportation fuel would require a different logistics network, different processors, different buyers and likely a different policy framework to make the economics work.

What would have to change before kelp could power ships or planes

For kelp to become meaningful fuel, several things would need to happen at once:

• Faster-growing strains would need to raise yields enough to support larger harvests.
• Harvesting would have to become efficient without adding too much boat fuel or labor cost.
• Processing would need to convert seaweed into usable intermediates without losing too much energy in the chain.
• Supply chains would need to expand far beyond current food-market volumes.
• Certification and regulation would need to accommodate a marine-grown feedstock inside the existing renewable-fuels system.

None of those hurdles is trivial. Together, they explain why the most honest case for kelp is not that it will replace oil, but that it might one day become one more feedstock in a broader decarbonization strategy.

The real takeaway

Kelp is attractive because it shifts the biofuel debate away from land use and toward the ocean, where the resource base is large and the agricultural inputs are lighter. But the seductive part of the idea is also the risky part: the easier the concept sounds, the easier it is to underestimate the industrial work required to make it real.

For now, the story is less about a miracle crop than about a long commercialization climb. Woods Hole’s red-light chambers, Delaware-style policy architecture, Maine’s expanding harvests and early DOE-backed projects all point in the same direction: kelp has a plausible future in transport fuel, but only if scale, cost, processing and energy return stop working against it.