For every scenario, electricity was the largest expense, accounting for over 45 percent of total cost on average. In states such as Mississippi and Texas with low electricity prices, production costs came down over 20 percent, making it possible to produce fishmeal from methane for $1,214 per ton, or $386 less per ton than conventional fishmeal production. Electricity costs could be reduced further, the researchers say, by designing reactors that better transfer heat to require less cooling, and switching electric-powered applications to those powered by so-called stranded gas that would otherwise be wasted or unused, which can also reduce reliance on grid electricity for remote locations. In scenarios involving methane from wastewater treatment plants, the wastewater itself could be used to provide nitrogen and phosphorus, as well as cooling.

If efficiencies like these could bring down the production cost for a methanotroph-based fishmeal by 20 percent, the process could profitably supply total global demand for fishmeal with methane captured in the U.S. alone, according to the study. Similarly, the process could replace soybean and animal feeds if further cost reductions were achieved.

“Despite decades of trying, the energy industry has had trouble finding a good use for stranded natural gas,” said study co-author Evan David Sherwin, a postdoctoral researcher in energy resources engineering at Stanford. “Once we started looking at the energy and food systems together, it became clear that we could solve at least two longstanding problems at once.”

The study was funded by the Stanford Center for Innovation in Global Health and the Stanford Natural Gas Initiative.

Criddle is also a senior fellow at the Stanford Woods Institute for the Environment, a member of Stanford Bio-X and an affiliate of the Precourt Institute for Energy.

Co-author Adam Brandt is an associate professor of energy resources engineering and senior fellow at the Precourt Institute for Energy, and co-author Stephen Luby is a professor of infectious diseases, a senior fellow at the Stanford Woods Institute and the Freeman Spogli Institute for International Studies, a member of Stanford Bio-X and the Stanford Maternal & Child Health Research Institute and director of research at the Stanford Center for Innovation in Global Health.

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