New energy-rich sorghum offers ethanol without the corn

As scientists around the world research biomass feedstocks — trees, shrubs and grasses that are designed to produce energy — a California startup called NexSteppe is betting that fast-growing, drought-resistant sorghum will emerge as a crop to sustainably fuel cars, trucks and power plants.

Sorghum, a millenia-old cereal grain, today feeds animals and people. It is turned into flour, syrups and beer, and used in gluten-free products. In Asia, sorghum is made into couscous, and across Africa, it’s consumed as a porridge.

Last year, though, NexSteppe introduced two new brands of sorghum seeds, dubbed Palo Alto and Malibu, that were bred expressly to be energy crops. They grow on marginal land and in a variety of climates, and they climb to a height of 20 feet after only four months of growth.

“Sorghum is naturally very heat and drought tolerant,” says Anna Rath, NexSteppe’s founder, president and CEO. “It originated in Africa. It’s a camel of a crop, if you will.”

Although NexSteppe has done almost no marketing outside of Brazil, its biggest market, the company’s sorghum is now being grown by farmers in 15 countries, including China, India, South Africa, Germany, Canada and the US.

“We identified a market need that wasn’t being met,” Rath told me, when we met at NexSteppe’s office in South San Francisco, across the bay from San Francisco International Airport. “Until now, crops have always been developed for animal feed and food—with the exception of cotton and tobacco. But there’s a growing need for energy that wasn’t being addressed.”

Rath, who is 38, is a former McKinsey consultant with degrees in biology and genetics, as well a doctorate from Yale Law School. She started NexSteppe with about $1m from friends and family in 2010. Since then, the company has raised about $40m from venture capitalists and from DuPont, which has major investments in biofuels, including a cellulosic ethanol plant under construction in Iowa.

NexSteppe isn’t the only company developing dedicated energy crops. Ceres, a small public company where Rath previously worked, breeds sorghum, switchgrass and miscanthus, but its products have been slow to reach the market. Meantime, the US government and university scientists backed by a 10-year, $500m grant from BP are extensively researching energy crops and biofuels production.

Why do we need dedicated energy crops? First of all, environmentalists say, reducing carbon pollution from the transportation sector will require widespread uptake of biofuels; vast, existing fleets of cars, trucks, buses and planes will need liquid fuels (but not gasoline or diesel oil) for decades to come. Second, most of the world’s biofuels today come from two feedstocks: corn in the US and sugarcane in Brazil. Neither is an ideal energy crop, experts say.

“We don’t view using food crops for fuel as a generally good idea,” says Heather Youngs, a senior fellow at the Energy Biosciences Institute (EBI), a BP-funded research project at UC Berkeley. EBI is doing basic research on an array of crops with appealing sustainability profiles, including perennial grasses like miscanthus. Since 2006, the US energy and agriculture departments have also funded basic research into the genomics of plant feedstocks for bioenergy.

Brian Siu, a senior policy analyst at the Natural Resources Defense Council, says biofuels ideally should be made out of organic waste or crops that don’t require much water or chemical use. “We have a lot of concerns with corn ethanol,” he says. “Corn is currently produced with a chemical-intensive process. It uses lots of fertilizers. It uses lots of pesticides.” Biofuels made from corn also cost more than fossil fuels, so they require government mandates or subsidies, which are controversial.

While sorghum is also grown for food, Rath says, it “needs a lot fewer carbon inputs than corn or sugarcane”. It also produces more biomass per acre per year than corn or sugarcane. NexSteppe has commissioned an independent analysis of sorghum’s sustainability profile, but it’s not yet available.

That said, unlike corn or sugarcane, NexSteppe’s crops have been bred to optimize energy production. Its Malibu sweet sorghum is designed to produce easily accessible fermentable sugars for fuels, while its Palo Alto high-biomass sorghum aims to deliver a low-moisture feedstock for cellulosic biofuels and biomass boilers that produce heat and electricity. The company, which employs about 35 people, half of them scientists, uses conventional breeding methods, and does’t use genetic modification.

Brazil is “our first, largest and most important market”, Rath says, because demand there is growing for both transportation fuels and electricity. Brazil also has dozens of ethanol plants and biomass boilers that are hungry for feedstocks to supplement local sugarcane. She sees opportunities for growth in China as well as in the US, where a half dozen or so cellulosic ethanol plants are expected to begin commercial production this year.

Over time, a variety of feedstocks are likely to emerge, depending on local conditions as well as government policy. Says Heather Youngs of EBI: “There’s a saying that ‘all biomass is local’ and it’s really true.” The NRDC’s Brian Siu agrees, saying that the sustainability profile of a biofuel is “highly determined by the feedstock and how and where we choose to grow it”. “The ‘how’ and ‘where’ are very important,” he says.

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