Power-to-X turns surplus wind and solar electricity into hydrogen, chemicals, heat, and other useful products.
On days where there’s lots of wind and solar energy available, that energy could be turned in to something else: X? Power to gas, or ever power to fertilizer.
Power to gas
The X getting the most attention is hydrogen. Electricity can be used to split water (H2O) into hydrogen and oxygen, a technique known as electrolysis that dates back to 1800 and is well known to even grade school students.
Hydrogen can then be used in fuel cells, gas turbines, or engines to make electricity, or can be used as a feedstock in synthetic natural gas or other chemicals. Hydrogen can be mixed with natural gas and stored in natural gas pipeline and underground storage systems. Existing gas systems in Europe can hold 12 times more energy than current pumped hydro systems.
There are at least 18 power-to-gas demonstrations underway in Germany with more in the works, according to the European Power to Gas Platform. The consulting firm DNV GL, writing in a paper for the European Power To Gas Platform, says the transportation sector is especially key in commercializing power-to-X technologies. Honda and Toyota are both selling passenger cars that run on hydrogen, while a variety of ships, buses, planes, and industrial vehicles are experimenting with hydrogen fuel cells.
But while electrolysis technologies are well known, they are currently a significant cost barrier to producing renewable hydrogen. “For many of the above mentioned functionalities of power-to-gas there is currently not yet a business case,” DNV writes. “Significant cost reductions and efficiency improvements are required to enable its deployment on commercial scale.”
The Power-to-X Alliance, composed of Audi, Airbus, and other companies, proposed legislation in Germany in November that would help commercialize power-to-X technologies, with incentives based on tons of carbon avoided.
Power to fertilizer
Europe is far ahead of the US on power-to-X, where it is still largely considered an exotic concept. But one innovative project is exploring the potential for wind power to improve farming practices.
The University of Minnesota at Morris formally dedicated a project in 2013 to start using wind power to make synthetic fertilizer for farming. Producing nitrogen-based fertilizers accounts for roughly 40% of the energy that goes into producing corn, increasing the carbon footprint of meat, dairy, and ethanol. Moreover, nitrogen is itself a potent greenhouse gas. When it emits from the soil in the form of nitrous oxide (N2O) it has a global warming potential almost 300 times that of CO2.
Because air is 78% nitrogen, researchers in Minnesota are able to use wind-powered electricity to pull nitrogen from the air and to split water into hydrogen. The Haber-Bosch Process, developed by two German scientists in the early 1900s, was key to creating the large amounts of low-cost fertilizer that enabled the explosion in farm productivity in the 20thcentury, known as the Green Revolution.
University of Minnesota graduate Norman Borlaug developed varieties of wheat in the 1940s that could thrive on the synthetic fertilizer. He won the Nobel Prize as the “father of the green revolution” and is credited with the food production that saved one billion lives across the globe.