Per Capita Davis: More about hydrogen
But first, I want to clarify something a reader pointed out to me in the prior column, where I stated, “Once you get it into a car’s fuel tank, it can power the car without producing any greenhouse gases. Combustion in the engine results only in water coming out the tailpipe.” Mostly true, but the statement contains a significant error. Namely, there is no “combustion” in a hydrogen-fueled vehicle. This is, of course, also the case in an electric vehicle and it deserves some explanation.
Whereas electric vehicles are battery powered, hydrogen vehicles rely on fuel cells consisting of both a positive and a negative terminal, much like a battery. Oxygen is inserted to the negative terminal. Hydrogen from the car’s fuel tank is fed into the fuel cell to the positive terminal, where a catalyst strips off its electron and passes it to an electric motor that powers the vehicle. The remaining part of the hydrogen (a proton) misses its minus and is attracted to the negative terminal and passes through a membrane to combine with oxygen to form water. Voila. Power is produced from a process called electrolysis and water is the by-product.
But, how does the hydrogen get into the fuel tank in the first place? This is where the argument against hydrogen as a fuel has found one (there are others) of its biggest barriers to widespread adoption. As indicated in the prior column, there’s not much hydrogen just floating around in the air. One estimate compares it to two liters of water randomly mixed into an Olympic-sized (50 meters; 2,500,000 liters) swimming pool.
So, we have to manufacture hydrogen, and this currently involves using methane as a feedstock and CO2 as a by-product.
But there is a better way, and the result of this other process is what is coming to be called “green hydrogen” produced from water via an “electrolyzer” using renewable energy to drive the process. This device is basically a positive electrode and a negative electrode separated by a membrane. When water is introduced and electricity is supplied, the water splits into hydrogen and oxygen. The hydrogen is harvested.
Sounds simple, but currently, it’s expensive to manufacture and operate an electrolyzer that can produce hydrogen at a scale commercially competitive with the current process. Though, the forecast by some is that this could happen as soon as 2030 due to both declining costs for renewable energy to power the process as well as advances that have resulted in declines in the cost of the electrolyzers.
And this not all theory — there are large investments being made in green hydrogen. To list a few: ITM Power, a manufacturer of electrolyzers, has contracted for, or has bids on, $300 million worth of electrolyzers; the German company ThyssenKrupp is targeting 10 GW capacity to meet that country’s COVID-19 stimulus package goal for green hydrogen; and the government of Australia recently announced funding of $70 million for hydrogen projects.
Utah’s Intermountain Power Project is shutting down a 1,800 MW coal plant to be replaced by a two-unit plant capable of burning 30 percent green hydrogen with 70 percent natural gas by 2025 and 100 percent hydrogen by 2045 that will be managed by the Los Angeles Department of Water and Power. The U.K. is examining hydrogen as an alternative to installing new electricity infrastructure to replace diesel locomotives. (More about hydrogen and trains in a future column.)
This one sounds a bit on the speculative side, but Nikola Motors, a firm in Arizona that intends to manufacture zero-emission vehicles, is reported to be offering a seven-year, 700,000-mile lease for hydrogen-powered trucks that includes filling stations “in multiple states and trucking routes” and has purchased 85 MW of green hydrogen production capacity to supply planned heavy-duty vehicle filling stations.
A friend, and expert on all things transportation, let me know that, “The most recent big focus on H2 in transportation is on big vehicles or marine vessels where the need for fast filling is important and a small number of stations can do the job.”
Hydrogen production facilities in close proximity to ports, trucking centers and businesses reliant on specialized heavy-duty vehicles such as the steel and chemical industries, using renewable energy produced on site or nearby, combined with a relatively small number of filling stations, can reduce some of the remaining barriers to widespread adoption of hydrogen fuels, including the requirement to liquefy and transport and the current lack of a refueling infrastructure.
As a parting thought, doesn’t it seem strange that as a hydrogen-fuel future potentially unfolds in front of us, we refer to the current liquid fuel we pump into our cars as “gas” and where we get the fuel as a gas station?
— John Mott-Smith is a resident of Davis. This column appears the first and third Wednesday of each month. Please send comments to firstname.lastname@example.org.
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