Since we’re continuing to dump greenhouse gases into our air that come from our use of fossil fuels, the Earth really is getting warmer. The average temperature has risen 1.5 degrees Centigrade since the 19th century. While it sounds like such a modest change, serious weather-related consequences are increasingly frequent around the world.
In addition to droughts, floods, rising seas and ocean acidification, there are record-busting tornados. In December 2021, tornados ripped through five states in a few hours; winds reached 150 mph; nearly 100 people were killed; and 400,000 lost power
This is our new climate.
If we can limit the rise in the world’s temperature to 5 degrees Centigrade, we’re told maybe the worst effects of climate change can be endured. But how can we stop using fossil fuels?
You may already know the answer: Electricity from renewable sources. And hydrogen.
Hydrogen is a colorless gas that can be thought of as electricity in disguise. It does not occur naturally in useful amounts, but it can be made cleanly from electricity and water with a device called an electrolyzer. It can be turned back into electricity with a fuel cell, with water again as the only byproduct. Year by year as the cost of renewable electricity declines, the cost of hydrogen made from renewables declines in turn. It is expected to achieve cost parity with fossil fuels by 2025.
Until recently hydrogen was made using fossil fuels, resulting in the release of the greenhouse gas CO2 in a process called steam reformation.
But that was then. Now, “green” hydrogen can be made by splitting water through electrolysis using electricity derived from renewable sources like solar and wind power. Soon the cost of green hydrogen will become cheaper than “black” or “brown” hydrogen, which is made from black or brown coal. Hydrogen can also be made from natural gas or methane, which is inexpensive, but the process produces CO2. If that CO2 is captured and pumped into the ground rather than released into the air (carbon capture and sequestration) this is “blue” hydrogen. If nuclear energy is used to split water, it’s called “pink” hydrogen. Most interesting is “yellow” hydrogen, which is produced in solar panels by a process related to electrolysis.
Diverse private industries are paying attention to the declining costs of renewables and green hydrogen. Especially exciting is using hydrogen to clean up industries that were considered difficult to abate, such as heating, transportation, production of basic materials like steel and cement, and energy storage.
For heating, hydrogen can be mixed with natural gas, delivered via existing pipes and burned in boilers or furnaces. This is already taking place in the United Kingdom.
For transportation, the batteries in today’s electric cars offer a useful range of a few hundred miles. That range will improve, but automotive batteries remain expensive and must be replaced eventually. In contrast, hydrogen can be compressed, raising its energy density beyond that of fossil fuels or conventional batteries, enabling hydrogen to power heavy trucks and trains. Its use in ocean-going ships and even airplanes is being planned.
Hydrogen also has useful chemical properties that will clean up other uses. It can be used to make ammonia for fertilizer, steel from iron ore, and the fuel and industrial chemical methanol. If that hydrogen is made from renewables, these industrial products become green, since no carbon dioxide is produced. The Swedish company Hybrit, owned by steelmaker SSAB, is already making green steel and its customers are familiar: Volvo and Mercedes.
Hydrogen is helping Europe store excess wind energy. Offshore wind farms in Germany and the U.K. at times produce much more electricity than their grids can accept. Last year German utilities curtailed $1.5 billion and U.K. utilities curtailed $227 million worth of electricity because of this imbalance. Storing this energy by making hydrogen would yield significant savings. European companies now propose making the green hydrogen at sea as part of the wind farms and storing it in salt caverns in the seabed.
Back on land, almost all utility-scale solar plants that rival the output of old-fashioned nuclear plants are now built with on-site energy storage using either batteries or hydrogen. This enables large renewable installations to integrate their production with the grid, much like coal or gas plants of the last century.
We can hope that black, brown and blue hydrogen will fade and eventually disappear entirely, even as green, pink, and maybe yellow hydrogen become economically irresistible.
Richard Gelinas, Ph.D., whose early work earned a Nobel prize, is a senior research scientist at the Institute for Systems Biology. He lives in Lakebay.
Suggestions for further reading:
“Where the Tornados Struck, Destroying Buildings and Homes,” The New York Times, Dec. 12, 2021
“Humanity Must Take a Stand on Climate,” The New York Times, Aug. 15, 2021
“The Hydrogen Colour Spectrum,” The National Grid Group (U.K.)
“Another Look in the Toy Box,” The Economist, July 4, 2020
“Green Hydrogen Developer Fears Electrolyzers Will Quickly Sell Out When the Ketchup Effect Kicks In,” Leigh Collins, Dec. 15, 2021; in ‘Recharge’ part of the NHST Media Group (online)
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