BMW Reapproaches Hydrogen
Top engineers in Munich talk about the vital role of H2 fuel cells in the climate crusade as iX5 test-fleet production begins.
Automakers have raised and dashed hopes for using hydrogen to power cars and trucks, including General Motors’ notorious 2007 promise that it would sell 1 million fuel-cell vehicles annually (actual number: zero). With EVs now seizing the lead in showrooms and public infrastructure, hydrogen might still seem dubious. But the complexities of global electrification have many OEMs and policymakers willing to give our lightest atomic element another chance.
BMW is convinced that without hydrogen supplementing the energy mix — including for large trucks that are poor fits for battery propulsion – the transportation sector and nations have little chance of keeping global temperatures in check. BMW is the first German automaker to sign onto the United Nations’ “Race to Zero” pledge, as BMW aims to reach full carbon neutrality by 2050.
“Hydrogen is a versatile energy source that has a key role to play,” said Frank Weber, member of the BMW board of management. “We are certain that hydrogen is set to gain significantly in importance for individual mobility.”
iX5 system details
Recently in Germany, BMW took journalists behind the scenes of the new iX5 Hydrogen fuel-cell SUV as it kicked off pilot-plant production, part of a test fleet that will begin operation this spring. Based on the South Carolina-built X5, the iX5 ditches a gasoline engine for a 125-kW (170-hp) fuel-cell stack and rear-axle electric motor. The system is fed by an enormous pair of underfloor tanks (at an industry-standard 700 bar/10,150 psi) that hold 6 kg (13.2 lb.) of hydrogen; conveniently, one hydrogen kilogram holds the energy equivalent of one gallon of gasoline. The traction motor and small 2.5-kWh battery fill in power gaps from the fuel cell with 150 kW (200 hp), and recapture energy via the vehicle’s brakes.
The upshot is a total 275 kW (369 hp), a 500-km (311-mi.) range and 190-km/h (118-mph) top speed. Easy, EV-crushing refills take less than five minutes. Easy, that is, if one can find an H2 oasis. Pumps for hydrogen — currently priced around $7 to $10 per gallon in the U.S. — remain scarce worldwide, with about 320 public stations in the EU and U.S. combined. Where it’s even available, hydrogen’s per-mile costs are two to three times that of gasoline, in part because few companies manufacture or supply the gas for retail. And that hydrogen is almost exclusively manufactured using energy-intensive fossil fuels, mainly natural gas.
It’s the chicken-and-egg scenario from the pre-Tesla EV era: What hydrogen passenger vehicles exist, including a Honda CR-V-based model coming in 2024, end up being a mirage in showrooms.
In the 2000s, BMW fiddled with burning cryogenically stored hydrogen in the ICE engines of a short run of 7-Series sedans. Two decades later at the company’s Hydrogen Competence Center near Munich, engineers showed their latest tech. BMW’s fuel-cell system, developed in-house, starts with wafer-thin bipolar plates — about the size of a home A/C filter — sourced from partner Toyota; the plates are the same as those in the Japanese automaker’s Mirai. A turbo-like electric compressor forces hydrogen into sandwiched plate membranes, whose catalyst separates hydrogen molecules into protons and electrons. Those particles take separate paths to a cathode, electrons create a flow of electricity and water vapor is the green byproduct.
The individual cells are inspected by vision machines to ensure no leakage of escape-prone H2. An automated process precisely stacks and compresses hundreds of cells. The resulting stack is sealed in a housing and mounted in the rear carrier of the X5.
As with previous fuel-cell bids, this might all seem quixotic. And proponents like Thomas Hofmann, BMW hydrogen project manager, acknowledge every hurdle. But they insist that if fully renewable, carbon-free transportation is the ultimate goal, EVs and their infrastructure can’t possibly serve every vehicle or use case.
Electricity “is unlikely to work 100 percent of the time,” says Hofmann, who co-authored a major white paper on the hydrogen economy for VDE Renewables, a quality-assurance service provider. According to his paper: Electricity generation from wind and solar is subject to strong daily and seasonal fluctuations. The potential to produce green electricity also varies greatly geographically. Hydrogen provides an optimal solution for bridging the gap between volatile generation and the need to supply green energy on-demand across all sectors.
While BMW is focusing on passenger vehicles, the company still sees medium-to-large trucks as hydrogen’s optimum play. “The heavier and larger the vehicle, the more hydrogen makes sense,” Hofmann says, as EV batteries deliver ever-diminishing returns in range and cost.
Unlike electricity, hydrogen can be cheaply stored and moved via pipeline, the BMW engineers noted. It can diversify the energy supply chain and buttress it against shortages: The iX5 requires no lithium, cobalt or nickel. Hydrogen could fill gaps in transportation that are more expensive or impractical for electricity. Pointing to a German infrastructure study, the BMW experts argue that building two complementary infrastructures — electricity and hydrogen — ultimately would cost less than electricity going it alone. As for a near-absence of renewable hydrogen, a Sept. 2022 analysis by McKinsey & Co. asserts green hydrogen’s price will quickly fall below that of fossil hydrogen as market penetration expands.
H2 backers also cite major governmental and environmental momentum for hydrogen, including support under President Biden’s Bipartisan Infrastructure Law, and growing fealty to the Paris Accords. The EU is preparing rules calling for a minimum number of hydrogen stations. Hofmann’s study projects a roughly $240 billion global investment in hydrogen through 2030. Yet the paper cautions that current hydrogen investment remains largely tied to global subsidy programs, with major uncertainty over expected return on private investment.
That uncertainty extends to showrooms. BMW’s iX5 is strictly a technology testbed. BMW does intend to sell its first series-production fuel-cell model by the end of the decade, however — around the time it projects having 10 million EVs already on the road.