Green Hydrogen’s Role in Enabling Zero-Emissions Transportation – Part One

Abstract

Hydrogen is likely to play a key role as we transition to low/zero-emissions transport. While battery-powered vehicles dominate in cars and light trucks, it will be a different story for ocean-faring ships and possibly for long-haul trucks and trains, where the unique advantages of hydrogen-derived fuels are more important.

Article

The Hydrogen Economy—Vision for the Future … or Hallucination From the Past?

In his 2003 State of the Union address, President Bush said “Tonight I’m proposing $1.2 billion in research funding so that America can lead the world in developing clean, hydrogen-powered automobiles.” The White House issued their Hydrogen Economy Fact Sheet. There was considerable excitement about moving to a hydrogen economy—in which the economy and most vehicles and vessels are powered by hydrogen fuel. Fast forward 20 years and it sure looks like battery power has won and hydrogen fuel cells have lost the battle for a zero-emissions power source for vehicles. In the U.S., about 660,000 battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) were sold in 2021, vs. slightly over 3,300 hydrogen-powered vehicles1 (aka Fuel Cell Electric Vehicles or FCEV). That means that hydrogen-powered cars represent a mere 0.5% of ‘zero emission’ vehicles being sold (and an almost invisible 0.02% of all light vehicles sold).2

Battery power, rather than hydrogen, seems to be the power source of choice for zero-emission delivery vans as well. Amazon ordered 100,000 battery electric delivery vans from Rivian Automotive in 2019. Even for big class 8 trucks, most manufacturers3 are coming out with BEV (battery) powered rather than FCEV (hydrogen fuel cell) powered trucks. We have also seen battery-powered electric cargo ships and ferries such as the Yara Birkeland, MS Medstraum, and MS Wellingdorf. There are some battery-powered trains, like Wabtec’s FLXdrive locomotives, Alstom, Hitachi Rail, and Parallel Systems autonomous trains. There are even a few battery-powered airplanes in the works, such as the Heart Aerospace ES-30 and Eviation’s Alice.

High Cost of Hydrogen Fuel and an Almost Complete Lack of Hydrogen Fueling Stations

Source: Ivan Radic, CC BY 2.0, via Wikimedia Commons

Why did batteries seemingly win over hydrogen? First is the high cost per mile for hydrogen fuel. As of November 2022, in California, a typical hydrogen FCEV (Fuel Cell Electric Vehicle) costs about $0.30/mile for fuel, over four-times higher than the $0.07/mile cost of operating an equivalent BEV (Battery Electric Vehicle).5 Even more of a factor is the dearth of hydrogen fueling stations. In the U.S., as of April 19, 2023, there are 61 public hydrogen fueling stations in the U.S., of which 60 are in California. There are almost 1,000 times as many BEV charging stations in the U.S.—52,810 stations, with 136,371 charging ports, of which 30,194 are DC Fast charging. This does not include privately owned residential charging stations, which provide BEV owners with even more convenience of charging their vehicles without even leaving the house. It is no wonder that hydrogen vehicles have been so slow to take off, while battery-electric vehicles are on a tear.

The Score: Batteries 100, Hydrogen 0 … but It’s Not Over Yet

One might conclude that the battle is over; that battery power has triumphed over hydrogen power for zero-emission transportation. However, hydrogen fuel (in the form of ammonia) is still very likely to play a dominant role in ocean shipping. Hydrogen fuel cells may play an important (if not dominant) role in rail and long-haul trucking as well. The logistics behind these sectors are completely different than for passenger vehicles. The energy density and refueling time advantages of hydrogen become critical factors for these sectors. Furthermore, the magnitude of the per-mile price difference between hydrogen fuel vs. battery charging is expected to drop dramatically, as we will discuss in part two of this series.

The Energy Density and Refueling Time Advantage

Hydrogen has two major advantages over battery power:

  • Energy Density—Hydrogen is much more energy dense than even the most advanced Lithium Ion (Li-ion) batteries.
    • The specific energy (energy per unit of mass) of hydrogen is almost 150 times that of the best Lithium Ion (Li-ion) batteries (39,600 Wh/Kg vs. 270 Wh/Kg). Once you factor in the weight of a fuel cell, the advantage drops dramatically, but is still considerable.
      A hydrogen fuel cell typically has 2 to 10 times the specific energy of Li-ion Batteries.6
      Source: Image by Roo Reynolds, (CC BY-NC 2.0)
      Compressed hydrogen has 3.5 to 9 times the volumetric energy density (MJ/L)7 of Li batteries. Ammonia, which can be derived from hydrogen, is even more energy dense, with 5 to 15 times more energy per unit of volume (MJ/L) compared to Li batteries.8
  • Refueling/Recharging Time—Hydrogen or ammonia refueling times are 5 to 50+ times shorter than recharging comparable energy capacity Li batteries.
    • Refilling a typical hydrogen-powered car takes about 3-5 minutes, similar to refilling a gas tank.
    • Recharging a battery-electric car, using the fastest chargers available (DCFC chargers), takes 20 minutes to an hour.
      Level 1 and 2 chargers take much longer.9

These advantages make hydrogen fuel more attractive than battery power for ocean shipping and potentially attractive for rail, and long-haul trucking. More precisely, ocean shipping will use green ammonia derived from green hydrogen (more on that in part two of this series). For large ocean-going ships, traveling many thousands of miles across the seas with no opportunities to refuel, green ammonia appears to be the only viable option for very-low/zero-emissions today. Battery-powered ships may end up playing an important role for shorter distances .

Not All Hydrogen is Created Equal—The Hydrogen Rainbow

Hydrogen has a vastly different carbon footprint depending on how it is produced. As shown in Figure 1 below, hydrogen can be produced from coal gasification (highest level of CO2 emissions, unless carbon capture is done), from natural gas using steam reforming (with or without carbon capture), and via electrolysis. Electrolysis can be done using conventionally generated electricity (typically a mix of coal-fired, gas-fired, and renewables generation) or with electricity solely from renewable low/zero-carbon generation. Only the latter is considered to be ‘green’ hydrogen.

Diagram by ChainLink Research.  Data from Various Sources (see footnote 4)
Figure 1 – Understanding the Hydrogen Rainbow Colors

This does not mean that we are anywhere near a quick or immediate transition of ocean shipping to green ammonia. First, at today’s prices, green ammonia is about four times as expensive as the typical bunker fuels used in shipping today.10 More critically, there are almost no ships capable of running on ammonia and only a very small number of plants producing green ammonia. Decades of investment are required.

In part two of this series, we look at the massive infrastructure investments that will be required and the massive incentives being provided by the U.S. Federal government, the EU, and other governments. In part three, we examine the IMO’s aggressive net zero goals and the legal framework driving ocean shipping to adopt low- and no-emissions power, why green ammonia (derived from green-hydrogen) is likely to be the fuel of choice, and some initial projects already underway.


1 Source: Hydrogen Fuel Cell Car Sales Rebounded In 2021Return to article text above

2 Source: MarkLines: USA – Automotive sales volume, 2021Return to article text above

3 Battery-powered class 8 trucks are being shipped or announced from all of the existing major class 8 manufacturers: Daimler Freightliner, Peterbilt, Kenworth, Volvo, Navistar, and Mack, as well as startups or established electric car companies trying to enter this space, such as Nikola, BYD, and Tesla. — Return to article text above

4 Sources for Figure 1 data:
   ●  Black hydrogen CO2 emissions data from Thunder Said Energy—Costs of hydrogen from coal gasification?
   ●  Grey hydrogen CO2 emissions data from Forbes—Estimating The Carbon Footprint Of Hydrogen Production
   ●  Blue and Green hydrogen CO2 emissions data from Rocky Mountain Institute—Hydrogen Reality Check: All “Clean Hydrogen” Is Not Equally Clean
   ●  Black and Grey global production data from Center on Global Energy Policy—Hydrogen Fact Sheet: Production of Low-Carbon Hydrogen
   ●  Blue hydrogen global production data from International Energy Agency—Global Hydrogen Review 2022
   ●  Green hydrogen global production data from World Economic Forum—Grey, blue, green – why are there so many colours of hydrogen?Return to article text above

5 Source: Fresh blow for hydrogen vehicles as average pump prices in California rise by a third to an all-time high, Hydrogen Insight, November 10, 2022. — Return to article text above

6 Source: Fuel Cell and Battery Electric Vehicles Compared, published by the Department of Energy, which says a small 60kW fuel cell with a 4.5kg tank has almost 600 Wh/kg specific energy, compared to about 250 Wh/kg for high-performance Li batteries. The fuel cell’s specific energy advantage will increase for very large fuel tanks relative to the fuel cell’s weight, such as on long-distance ocean ships.  — Return to article text above

7 MJ/L = Megajoules per Liter. Joule is a measure of energy. A Megajoule is one million joules. — Return to article text above

8 The volumetric energy density of NH3 (ammonia) is 12.92–14.4 MJ/L; for H2 (liquid hydrogen) it is 8.49 MJ/L; and for lithium-ion batteries, it is 0.9–2.63 MJ/L, according to Limitations of Ammonia as a Hydrogen Energy Carrier for the Transportation Sector, Sudipta Chatterjee, Rajesh Kumar Parsapur, and Kuo-Wei Huang, ACS Energy Letters 2021 6 (12),4390-4394, DOI: 10.1021/acsenergylett.1c02189 — Return to article text above

9 According to the US DoT (Electric Vehicle Charging Speeds), Level 1 chargers will take 40-50 hours to charge a battery electric vehicle, Level 2 chargers take 4-10 hours, and Level 3 DCFC (direct current fast charging) chargers take 20 minutes to an hour to charge to 80%. — Return to article text above

10 Source: Renewables Now, Green ammonia costs double that of grey ammonia – Argus. Note: Green ammonia is about twice the cost of grey ammonia and grey ammonia is about twice the cost of bunker fuel. — Return to article text above

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