Nitrogen is the most abundant element in the Earth’s atmosphere but it is extremely difficult to sever its chemical bonds to other nitrogen atoms. It really prefers to stay in the form of nitrogen gas — N2 to you organic chemistry majors. Plants are capable of breaking down N2 in their root systems, but scientists have never been able to manage the same trick without expending massive amounts of energy — which often comes from burning fossil fuels.
Nitrogen makes excellent fertilizer and is largely responsible for the agriculture revolution that allows 1% of the population to feed the rest of the world’s population. A century ago, two German scientists — Franz Haber and Carl Bösch — devised a way to create nitrogen fertilizer, but it is an energy intensive process. Today, 2% of the world’s energy is devoted to making fertilizer using the method discovered by those German scientists, which means it has a rather large carbon footprint.
In 2016, Newsweek did a story on the nitrogen economy entitled “We Need A New, Sustainable Way To Make Fertilizer.” It interviewed two nitrogen researchers, Paul King, a photobiologist at the National Renewable Energy Laboratory, and Mercouri G. Kanatzidis, a member of the Northwestern Solar Energy Research Center at Northwestern University. Both have been experimenting with ways to use solar power to create ammonia, a molecule made up of one nitrogen atom and three hydrogen atoms.
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But there quest goes beyond just fertilizer. Ammonia is a way of storing energy — lots of energy, actually. The bomb Timothy McVeigh used to blow up the Alfred P. Murrah Federal building in Oklahoma City was a combination of fertilizer and diesel fuel. “Making fertilizer via Haber-Bosch is like making electricity at a big central coal-fired power plant — electricity that then needs to be transported hundreds of miles to its point of use,” says Newsweek.
“But with solar panels, electricity can be made where it’s used. With solar powered ammonia synthesis, so can fertilizer. And while electricity storage is tricky, storing ammonia is easy by comparison. You might imagine other systems of ammonia synthesis that rely on yet other forms of renewable energy.” John Holbrook, executive director of the NH 3 Fuel Association, says, “I can’t tell you how many times we’ve talked to people who want to take the output of their wind turbine and make their own fertilizer or fuel for the farm.”
These researchers have been toiling in the fields of nitrogen research for a decade or more without any assistance from the federal government. But in October of 2016, The US Department of Energy Office of Basic Energy Sciences brought Lance Seefeldt, a biochemist at Utah State University, and 16 other experts in nitrogen research together in Washington, D.C. to discuss the current field of nitrogen activation chemistry and its future directions. The results of their research were published in the journal Science on May 25.
“It’s an incredible irony,” Seefeldt tells Science Daily. “We need nitrogen to survive and we’re swimming in a sea of it, but we can’t get to it. Humans and animals get nitrogen from protein in our food. Plants get nitrogen from the soil. Our research on this process, which uses nanomaterials to capture light energy, demonstrates how sunlight or artificial light can power nitrogen fixation. It a potential game-changer.”
Renewable energy advocates will immediately recognize the conflict involved in using excess solar or wind power to create hydrogen or ammonia. Neither is really a fuel. Both are actually ways of storing energy for use later. True believers in renewables suggest if there is any excess electricity lurking about somewhere, it should be stored in a battery, not used to power chemical reactions.
The response is that all methods of weaning the world off fossil fuels are vitally important. Some will be advantageous in certain situations, others will be particularly suited to other applications. The world will need all of them to break the stranglehold of fossil fuels.
Paul King believes the key to transitioning away from fossil fuels to sustainable energy sources will occur when carbon fees become commonplace, destroying the unfair economic advantage fossil fuels enjoy because the social costs of using them are not included in their price. “Humanity doesn’t need to recognize value in nitrogen; it needs to see danger in carbon,” reports Newsweek. Exactly.