Fertilizer is an end product in a very different venture under way at the University of Minnesota at Morris.
A $2 million, 1.6-megawatt wind turbine installed in 2005 generates supplemental electricity for the 1,800-student campus, while about 20 percent of the juice is sold to Fergus Falls–based Ottertail Power Company. In a pilot project now in the design phase, sales to Ottertail will decrease as the wind turbine becomes the power source for a $3.75 million facility housing an electrolyzer that captures hydrogen from water.
Hydrogen is the main component of anhydrous ammonia, which is the main component of nitrogenous fertilizer. Given that a world powered by hydrogen fuel cells is still far from reality (see The Elusive Hydrogen Economy), anhydrous ammonia is an excellent and economically promising use for hydrogen, says Michael Reese, coordinator of the Minnesota West Central Research and Outreach Center at the Morris campus. It gives the hydrogen immediate value, and because the fertilizer is a liquid, it’s practical to store and ship it; one pound of hydrogen gas fills an 800-gallon tank.
Separating hydrogen and oxygen from water in an electrolyzer—essentially a water tank into which electricity is introduced—is an old technology used more extensively in the 1920s than today, Reese says. In the 1950s, it became cheaper to extract hydrogen from natural gas via a process called steam methane reformation. But that requires very large facilities and releases carbon dioxide, a greenhouse gas. Since the price of natural gas began to rise sharply in recent years, some 40 percent of American producers of anhydrous ammonia have gone out of business, Reese says.
The cost of electrolysis and of the steam methane method are now roughly equal, and the world’s largest manufacturer of electrolyzers, $26 billion Norsk Hydro of Norway, has taken a keen interest in the Morris project, providing research help and supplying the electrolyzer.
Prior to spinning off its fertilizer business in 2005, Reese explains, Norsk Hydro also was the world’s largest fertilizer company. From its perspective, a successful pilot project in Morris could lead to a new market for the company’s water-to-hydrogen-to-ammonia technology, as any wind turbine in a farming area could become the power source for a local fertilizer plant.
The university does not expect to profit from the operation. “It will cost us money to do the fertilizer process,” Reese says. “What we hope to do is provide the information necessary to commercialize it.” The project will have the potential to make 360 tons per year of nitrogen fertilizer, but probably will produce less. “What we don’t use on the university’s own research corn crop, we’ll sell to a local co-op,” he says.
The potential, however, is far reaching. Collectively, all of the wind turbines that now generate electricity in Minnesota have a bit less than 1 gigawatt of capacity. According to Reese, it would take only double that capacity for wind power to produce all of the nitrogenous fertilizer used by every farm in the state.
