Imagine a colorless, odorless gas that bubbles spontaneously out of the ground, combines freely with oxygen, releasing huge amounts of usable energy through a reaction whose only waste product is water.
Sounds like a science fiction answer to our energy and climate problems, but there is such a gas - it's hydrogen - lighter than air, relatively harmless, and the stuff that fuels the energy of the stars. And while much research funding goes into trying to create that stellar energy source on Earth through fusion - the melding of two forms of hydrogen into helium - it is the spontaneous, low energy combination with oxygen that offers that utopic vision of our energy future.
And low energy is a relative term, as it was the combination of hydrogen and oxygen, loaded separately into the booster rockets of the now-defunct Space Shuttle that, when brought together, powered booster and shuttle into space.
For industrial uses, the hydrogen-oxygen reaction can be harnessed to generate the extremely high temperatures required for refining iron ores, or used in place of fossil fuels to power cars and trucks. At the lowest end of the power spectrum, hydrogen can be combined with oxygen in low-temperature fuel cells to generate electricity - and just water.
The energy content, range of applications, and low impact of waste product might be enough to make us dream that this smallest of molecules is the answer to our energy and climate crisis. And hydrogen-based proposals have been around for many years.
So why hasn't the hydrogen revolution happened? One serious limitation often absent from the more promotional writings on the subject is that hydrogen is rare in the natural world. There are no hydrogen "mines" - but more on that in a moment.
And while hydrogen gas (H2) can be created by splitting two atoms of this element out of water (H2O) or methane (CH4), both processes are energy- and carbon-intensive using conventional energy sources.
Hydrogen is also difficult to store and transport. Condensing hydrogen into a liquid requires extremely low temperatures. Storage under pressure, as required in vehicles, runs all the risks of handling any compressed gas, plus one more - the oxygen/hydrogen reaction can be explosive. Images of the Hindenburg airship disaster, where this hydrogen-filled "blimp" ignited, crashed, and burned in a matter of seconds, are still with us.
For all of these reasons, driving a car fueled by compressed hydrogen, one of the earliest proposed large-scale applications of hydrogen power, has proven to be a hard sell. As of 2020, only 31,225 hydrogen-powered cars had been sold worldwide and there were fewer than 50 hydrogen fueling stations available in the U.S.
The massive switch in energy infrastructure required to convert a large part of the global fleet to hydrogen would have been extremely expensive, especially in comparison with a switch to electric vehicles (EVs) that can tap into the existing grid system. With 7.8 million EVs sold worldwide in 2022 alone, the car-buying public and car manufacturers have clearly chosen the EV pathway over the hydrogen option.
That said, there is still a significant market for hydrogen in industrial uses, especially in oil refining and the production of ammonia, methanol, and steel. Global demand has quadrupled since 1975, with almost all hydrogen being produced from fossil fuels. According to the International Energy Agency, producing one gram of hydrogen gas causes the release of 10 grams of carbon dioxide.
So while there are several ways to peel hydrogen gas (H2) from water or methane, they are all expensive and energy- and carbon-intensive. Storing and transporting this gas only adds to both the hazards and the cost. As a result, there will be no significant role for hydrogen energy in reducing greenhouse gas emissions unless there is an untapped natural source of the gas, or a low-carbon way to produce it close to where it would be used.
And both have been proposed.
The production of steel is incredibly energy-intensive. Monstrous digging machines and the world's largest dump trucks consume huge amounts of diesel fuel in the mining of iron ore. Blast furnaces used to refine the iron ore require extremely high temperatures and now consume 12% of the annual world supply of coal - and generate between 5% and 8% of global carbon dioxide emissions.
The term "blast furnace" conveys the energy intensity of the process, which essentially reproduces the reactions by which the iron-rich core of the Earth was formed. When very high temperatures (over 1,900 degrees Celsius or ~3,500 Fahrenheit) cause the ore to melt, the denser iron sinks preferentially to the bottom of the furnace (or in the early Earth, towards the center of the planet) and is drained off, leaving other residues known as "slag." "Blast" comes from the practice of forcing compressed air into the fuel mix to increase oxygen flow and raise the temperature.
Recent tests have demonstrated that hydrogen can be used to augment coal in blast furnaces, and in one case to replace it completely, so there is the potential for coal-free steel production. But where can the world find that much hydrogen, and hydrogen produced from renewable, non-carbon-emitting energy sources? "Green" hydrogen would require large amounts of renewable energy, and constraints on shipping the gas would suggest using it where it is produced.
So we seek a place where a large source of iron ore is located in a remote area with abundant sunshine and wind and without competing land uses.
And where might you find that? How about Western Australia?
Australia
It is this article from the New York Times that made me rethink the very strong skepticism I have held about the possible role of hydrogen in moderating the rate of climate change. What follows here is abstracted from that excellent article.
The Pilbara region near Australia's west coast is the source of ~40% of the iron ore in the world, and the site of one of the biggest mining operations on Earth. The fossil fuel and carbon footprints of this operation are immense.
The owner of the mines in this district is making a huge, and possibly risky, investment in alternative energy and green hydrogen. The scale of the project is as immense as the challenge. In collaboration with BP Energy, the plan is to install 1,743 wind turbines and about 10 million solar panels to generate 26 gigawatts of electrical energy, none of which will be exported to the national grid. It will be used first on site to power all aspects of the mining operation. Trucks operating close to mines or shipping points will be converted to battery/electric. Those requiring greater range will be converted to hydrogen.
But in the absence of a major industrial user in the region, most of the hydrogen produced, if this facility reaches full scale, will be exported for industrial uses across the globe. Overall BP and the Australian mining company, Fortescue Metals Group, are planning to invest hundreds of billions of dollars pursuing hydrogen production in Australia and at many other locations around the world.
Given hydrogen's current small footprint in the global energy economy, and the hurdles to overcome in shipping massive quantities of the gas over long distances, this seems to be a major role of the financial dice, but if accomplished using non-carbon energy sources, gains for the climate system could be significant.
Are there other places in the world where abundant renewable energy might allow the proof of concept needed for green hydrogen?
Iceland
Iceland has the highest percentage of energy drawn from non-carbon sources of any country in the word. Hydro supplies 75% of electricity, and geothermal energy from the abundant volcanoes supplies another 24% of electricity as well as steam to heat 85% of the nation’s buildings. With so much green electricity, Iceland was an early entry in the hydrogen business because of its potential value as a fuel for mobile sources like cars. This was before EVs became such a viable alternative.
Several false starts have been made. In 1999 Icelandic New Energy was established to promote a transition to "the first hydrogen society by 2050." The country's first hydrogen station opened in 2003 and avoided the issue of transporting this fuel by producing the gas on site. The hydrogen station was closed in 2010, but was reopened in 2018. An in-country program from 2002-2005 supported three buses and one fueling station. Another bus demonstration project in coordination with EU countries lasted from 2006 to 2007.
The current Icelandic national energy plan mentions hydrogen only once, in the same paragraph with gas production from organic wastes.
And yet there are a number of private companies and international think tanks dwelling on the potential of a bright future for hydrogen as an energy carrier. There is even one that has proposed a consortium of countries built around a hydrogen hub in the northeastern U.S.!
Are Hydrogen Mines in Our Future?
Which brings us back to that teaser line at the top about the possibility of mining naturally occurring hydrogen. While it is hard to imagine that such a possibility could have gone untested for so long, there is a resurgence in the discussion of where and how much hydrogen is produced in Earth's crust, and whether there is enough to support a hydrogen-electricity industry.
A recent scientific paper (see Sources below) suggests that the potential is quite large, orders of magnitude more than previously estimated. A conference paper presents a simple box model of the production of hydrogen through naturally occurring reactions and again suggests that the potential for significant energy production from mined hydrogen exists. And a scientific blog suggests hydrogen can be made available at relevant volumes and notes how rapidly shale oil rose from nothing to be a $150 billion industry in 15 years. That blog does mention that this is new territory and urges caution and more research.
A recent editorial in the New York Times is very bullish about the future of hydrogen energy, likening it to a scientific revolution and the discovery of a cure for scurvy - a solution in plain sight. Anecdotes abound in uncharted territory like this, and one is presented here of a remote village in Mali where a borehole released a gas stream that was 98% hydrogen. Tapping that resource with fuel cells provides electricity for the first time to that village.
So it can happen, and it can work, but just how much of our energy future is in hydrogen remains an open question.
If hydrogen can be produced with wind and solar energy, and used where it is produced in applications like iron refining that can't be met with electricity alone, or if there actually are usable and economically extractable sources of free hydrogen gas that can be tapped and used directly, the offset to greenhouse gas emissions might be significant.
But the widespread use of this fuel in cars and trucks is likely a lost cause as the auto industry pivots strongly to electric vehicles, and any use that requires long distant transport of hydrogen gas appears unlikely to be economically or environmentally viable.
So I have pivoted as well, from being a total skeptic on hydrogen energy, green or not, to being open to the possibility that hydrogen might be one piece in the very large and complex puzzle we need to solve to reduce greenhouse gas emissions.
Sources
Images of the sun and the hydrogen-hydrogen reactions are from:
https://commons.wikimedia.org/wiki/File:Sun_poster.svg
https://www.energy.gov/science/doe-explainsnuclear-fusion-reactions
The image of testing of the Space Shuttle engine is from:
https://en.wikipedia.org/wiki/Hydrogen#/media/File:Shuttle_Main_Engine_Test_Firing_cropped_edited_and_reduced.jpg from: NASA-SSME-test-firing edit1.jpg
More recent rocket systems, including the SpaceX Raptor, use methane rather than hydrogen as fuel.
https://en.wikipedia.org/wiki/SpaceX_Raptor
The fuel cell schematic is from:
https://en.wikipedia.org/wiki/Fuel_cell#/media/File:Solid_oxide_fuel_cell_protonic.svg
The Hindenburg image is from:
https://commons.wikimedia.org/wiki/File:Hindenburg_disaster.jpg
Information on the processes for producing hydrogen gas can be found here:
https://en.wikipedia.org/wiki/Hydrogen#Production
Data on hydrogen car sales and stations are from:
https://en.wikipedia.org/wiki/Fuel_cell_vehicle
The number for EV sales in 2022 is from:
Carbon dioxide released per gram of hydrogen produced is from:
https://www.iea.org/reports/hydrogen-supply
Two sources reporting that steel production contributes 5%-8% of total carbon dioxide emissions are:
Assessment of Opportunities for CO2 Capture at Iron and Steel Mills: An Australian Perspective. Dianne E. Wiley, Minh T. Ho, Andrea Bustamante. Science Direct http://dx.doi.org/10.1016/j.egypro.2011.02.165
And
https://www.weforum.org/agenda/2022/07/green-steel-emissions-net-zero/
And fraction of total coal consumption is from:
https://www.statista.com/statistics/1279674/worldwide-coal-demand-share-by-sector/
The image of the iron ore mining machine is from:
https://commons.wikimedia.org/wiki/File:K%C3%BClszini_lignitb%C3%A1ny_Visont%C3%A1n.IMG_0404.JPG
Information on blast furnaces can be found here:
https://en.wikipedia.org/wiki/Blast_furnace
A description of the formation of the Earth's iron-rich core is here:
https://education.nationalgeographic.org/resource/core/
The smelter image is from:
http://wwwchem.uwimona.edu.jm/gifs/blast.gif
An article on a hydrogen-fueled iron furnace if here:
https://www.popularmechanics.com/science/green-tech/a29813424/steel-blast-furnace-hydrogen/
The story about the development of green hydrogen resource and its use in iron mining and refining is here:
https://www.nytimes.com/2023/03/11/climate/green-hydrogen-energy.html
An optimistic assessment from 2009 on the future for hydrogen in Iceland is here:
file:///C:/Users/johna/Downloads/209salameh.pdf
The image of a geothermal/electric plant in Iceland is from:
The history of hydrogen experiments in Iceland is from:
https://en.wikipedia.org/wiki/Energy_in_Iceland#Experiments_with_hydrogen_as_a_fuel
The current energy plan for Iceland is here:
Continuing private sector reports on a hydrogen future for Iceland include:
https://fuelcellsworks.com/news/hydrogen-revolution-powers-its-way-to-iceland/
Efforts to build a north Atlantic hydrogen network with a hub in the U.S. include:
https://atlantichydrogen.ca/
https://www.oceanhywaycluster.no/projectlist/nora
Scientific papers on the potneital mining or trapping of naturally occuring hydrogen for energy production include:
https://gsa.confex.com/gsa/2022AM/meetingapp.cgi/Paper/380270
The New York Times editorial on hydrogen is here: