When cars or industrial facilities burn fuels derived from plant matter, the carbon dioxide released is the same carbon dioxide those plants absorbed from the atmosphere to begin with.

That’s a simplistic way to look at it, of course. And it takes energy to grow all the biomass required to make biofuel, which makes this energy “cycle” far from perfect or self-sustaining. But it’s clear that biofuels have a huge role to play in our transition from fossil fuels to a truly sustainable and renewable future. Here’s a look at some biofuel raw materials that are showing promise.

Algal Lipids

The biodiesel industry definitely has its eye on algae. Algae are remarkable, even in the plant kingdom, because they can perform photosynthesis just like “full-size” plants, except without arable land, fresh water or the depletion of food crops. Their application in biofuels stems from their ability to produce “algal lipids.” This may be done in one of two ways: in an open pond, much like algae grows in the wild, or fermented in a bioreactor. Bioreactor systems grow algae in controlled conditions to maximize yield.

These systems haven’t been scaled up to meet industrial needs yet, but companies have been signaling for years that their ASTM-friendly biofuel mixtures derived from algal lipids (“algae oils”) are ready any time the infrastructure comes together. The American Society for Testing and Materials, or ASTM, is one of the bodies responsible for drawing up product standards for the transportation, construction and manufacturing industries.

Soybeans

The humble soybean is grown all over the world. It’s a food crop, but its ubiquity and the vast amount of available cropland devoted to it make it an appealing choice as a biofuel feedstock. The U.S. produces 32% of the world’s soybeans, making it the world’s largest producer. Brazil comes in second place with a 28% share of the market.

 

Companies like Monsanto and DuPont continue to introduce genetically modified soybean varieties. Some soybean types boast improvements in crop yield of up to 12%, without using up any additional land.

An acre of soybeans does not yield as much fuel as an acre of canola or even sunflowers, but soybeans are already a part of the growing cycle for many farmers, who grow it in turns with wheat or corn to break up disease cycles and insect infestations. Soybeans are already a big part of the biofuels industry and will continue to play a role as industries everywhere look to break their dependency on fossil fuels.

Castor Seeds

The most important mark of any biofuel or “transitional” fuel is that it’s reasonably sustainably produced, it can meet our present energy needs, and it doesn’t adversely affect the habitability of the planet for future generations. Castor oil is a material which seems to satisfy these requirements. It’s derived from the castor plant — a tropical variety partial to India, China and Brazil, making these the dominant markets for castor oil in the world.

 

Castor seeds are appealing to the biofuels industry because they contain a triglyceride-rich oil called ricinolein. With the right industrial process, this type of oil can step into the role currently filled by petrochemicals and go on to become any number of different end products.

 

Importantly, castor seeds aren’t fit for human consumption — and that means growing them won’t compete with food crops. While castor seeds do require land to grow, committing land to their cultivation yields a better return than other oil crops, including sunflowers, palm and rapeseed. Improvements in the production process led to total castor seed production across the world rising from 1 ton to 1.4 tons between 2003 and 2013 alongside a concurrent drop in prices.

Camelina

While agricultural companies work to squeeze the greatest yield possible of raw plant material, others are working on the problem of narrowing down the most high-yield oil crops available and then working out how to grow them at scale.

 

A relative of canola, camelina is one interesting candidate. It may compete with lands that are also suitable for growing wheat, including in the Upper Midwest of the U.S., but it has a short growing season, is suitable for soil of only marginal quality and is attractive economically because it has a lower break-even cost than other emerging oil crops, including canola and soybeans.

Cleaner Roads to Biofuels (And Beyond)

Ethanol did some of the heavy lifting already, butcompared with the other oil crops on this list, corn takes a lot of fertilizer and water — and it’s something human civilization has relied on for foot since prehistory.

The ideal way to go, as the biofuels industry plots its way forward, is to prioritize crops which don’t require prime cropland, make do with “marginal” crop acreage instead, and require a smaller share of the resources we need to feed ourselves. The candidates listed here aren’t perfect. They aren’t electric cars. However they’ve been working to help us break away from fossil fuels.

This Author

Emily Folk is a conservation and sustainability writer and the editor of Conservation Folks.