On cars, old, new and future; science & technology; vintage airplanes, computer flight simulation of them; Sherlockiana; our English language; travel; and other stuff
WHEN BILL MITCHELL, LARRY BURNS, AND CHRIS BORRONI-BIRD proposed mobility for this century, they envisioned a vehicle mix with propulsion depending upon size and distance.
Based on range and infrastructural constraints, Battery Electric Vehicles occupy the small size/short distance corner of the matrix. Hybrid Electric Vehicles and Plug-in Hybrids fill the midsection. For the largest size and longest distances, the optimal choice is Fuel-Cell Electric Vehicles.
These days, much of the hype and government push is on BEVs, with predictions that they’ll dominate the market by 2030, if not before. However, range, infrastructure—and time spent at the latter—still give credence to that upper right of the Mitchell/Borroni-Bird/Burns graphic.
Here in Parts 1 and 2 today and tomorrow are tidbits gleaned from a variety of sources, particularly on fuel-cell trucking.
Background. “If you got it,” the adage goes, “it got there by truck.” And, for one step or another of the process, this still holds true (despite depictions of neighborhood airspace filled with delivery drones).
“Fuel-Cell Trucking,” SimanaitisSays, September 2, 2016, discussed emissions-free semis having 1200-mile range. And, compared to battery recharging times, FC trucks have relatively quick fillups on par with diesel replenishment—once the hydrogen infrastructure is in place.
Elon Musk has twitted “Fuel cells = fool cells.” Others note progress is being made in exploiting this particular niche of the size/distance matrix.
Hydrogen Sourcing. Though hydrogen is the most common element in the universe, it is also among the most promiscuous. Hydrogen is produced commercially primarily from natural gas (48 percent), oil (30 percent), and coal (18 percent). Each of these breaks up hydrogen’s carbon romance, albeit freeing the latter to its environmental detriment.
The remaining four percent results from electrolysis, a process practiced by anyone taking a secondary school science class: Electricity splits water, H2O, into hydrogen and oxygen.
Efficiency of Production. Wikipedia notes, “Electrolysis of water is 70–80% efficient (a 20–30% conversion loss) while steam reforming of natural gas has a thermal efficiency between 70 and 85%.”
Hydrogen—Green or Blue. Electrolysis produces “green” hydrogen—but only if its required electricity comes from a renewable source. Otherwise, for example, coal-sourced electrolytically generated hydrogen fueling an FC semi may be no better source-to-wheel than its diesel counterpart. (Earlier research has shown that a BEV charged with coal-produced electricity is inferior, source-to-wheel, to its state-of-the-art gasoline-fueled counterpart.)
The term “blue” hydrogen describes steam reformation of methane, a component of natural gas, in which the byproduct carbon dioxide and other impurities are sequestered. This sounds like a good idea—especially because today methane is often flared at refinery stacks.
This time, the challenge focuses on source-to-tank, the to-wheel portion being a fuel cell cinch: Its efficiency exceeds 60 percent (versus internal combustion’s 20-35 percent); its emission is the purest of water.
Tomorrow in Part 2, the research continues: One study says blue isn’t all that green. Others describe cooperative efforts to keep on truckin’ with H2.
© Dennis Simanaitis, SimanaitisSays.com, 2022
“BEV charged with coal-produced electricity is inferior, source-to-wheel, to its state-of-the-art gasoline-fueled counterpart?”
I’ve seen much the opposite, but it clearly depends on the efficiency of the BEV. Use something near the higher-efficiency end of the scale, such as (at around 4 mi/kwh) Bolt and some of the lower-end Tesla Model 3s, and the BEV is certainly better than gasoline even when the power is fueled by coal. At the other end of the scale, a 1.5 mi/kwh Hummer is just a pig, though whether it’s better or worse than its <10 mpg gasoline (or diesel) fueled equivalent is hard to guess. Even in the worst case (CO2 emissions from power exceeding, probably only slightly, those of the equivalent gasoline-fueled vehicle) – no fair comparing a EV Hummer on coal to a Prius!), though, EVs do have lower localized pollutant emissions because there's no exhaust; the fossil-fueled models still produce some exhaust PM and NOx even after considerable aftertreatment, and even if the fuel itself is biologically-derived.
Check out https://afdc.energy.gov/vehicles/electric_emissions.html, from the U.S. Department of Energy: “All-electric vehicles and PHEVs running only on electricity have zero tailpipe emissions, but emissions may be produced by the source of electrical power, such as a power plant. In geographic areas that use relatively low-polluting energy sources for electricity generation, all-electric vehicles and PHEVs typically have lower emissions well-to-wheel than similar conventional vehicles running on gasoline or diesel. In regions that depend heavily on coal for electricity generation, EVs may not demonstrate a strong well-to-wheel emissions benefit.”
The term I always heard when discussing BEV green-ness was “deferred emissions”, and as you show, it’s an important consideration. Coal is our local primary source, but the percentage of renewable power has increased in the past decade, making vehicle charging more acceptable.
Still, the lemming train to BEV-mandates alarms me. I’ve often lived where fist fights would break out over insufficient parking — can’t imagine how multifamily home renters are expected to charge their cars. Why remove HEVs (like the one I already own) from the toolbox? The DoD has nukes, but still issues knives.
Plus, my city already has tiered pricing and restrictions on summer electricity use. Can the grid handle more BEVs? I imagine it takes a lot more kilowatt hours to move a ton and half down the freeway, than it does to dry a load of clothes, boil pasta, or cool a home.