WHY HYDROGEN IS A SMALLER PART OF OUR FUTURE THAN YOU THINK

May 11

THE FUTURE OF ENERGY

I LOVE HYDROGEN

I love hydrogen. It burns clean. Water as a by-product with no nasty greenhouse gases. It’s no longer part of the future of passenger cars, of course, where super-simple electric drivetrains and uber-low maintenance requirements already trump fuel-cells for almost all family requirements, and are plummeting in price, and will at least double in range with the new batteries coming, but hydrogen is awesome because it can power long-distance trucks and ferries, and offers long-haul aviation a pathway towards a (nearly) net-zero future [** not anymore:- see update at end of this article], and gives us a way to make steel without the coking coal. I’m especially excited about the steel. By all accounts the first-gen green steel produced by SSAB in Sweden and ArcelorMittal in Belgium is 10-20 percent more expensive than the coal-produced variety, which means regulatory mechanisms are needed to incentivise the transition, but as the world inevitably accounts for more of the social costs of carbon-release in manufactured products, green steel will reach cost-parity with the traditional variety and the mighty dollar will take care of the rest. Fabulous!

THE FORGOTTEN FACTOR

But lovely hydrogen can only ever be a SMALL part of our future. Here’s why:

It takes a LOT of energy to make it.
It takes a lot of energy to compress, liquify and transport it.
It wastes a lot of energy during combustion, especially compared to sending electrons direct to destination (electrification).

The first factor is the biggest, and the one most frequently forgotten in all the excitement. Electrolysis (using electricity to split water to make green hydrogen) requires a LOT of electricity!

The vast majority of projects today use steam methane reforming to make hydrogen, which is definitely not green because it releases a LOT of greenhouse gases. If they do use electrolysis, they mostly power the process with fossil-fuels, which is also very definitely not green. Obviously, we cannot continue making emissions and burning fossil fuels to make hydrogen as that defeats the point, and the universal promise of sponsors of such projects is they will all one day transition to clean, green, renewables-powered electrolysis. “We have to start somewhere,” they argue. “We’ll get this H2 plant up and running and THEN we’ll make the transition!”

They can’t. Not all of them. Not at the scale they’re hoping.

EXAMPLE: REPLACING THE GAS INDUSTRY WITH HYDROGEN

To illustrate, in my home country Australia, some important people are talking about hydrogen replacing the gas industry. Well, let’s do the math:

Australia exported 4,313 petajoules (PJ) of gas and used 1,568 petajoules in the domestic market in 2020-2021, for a total of 5,881 petajoules of energy.
1kg of hydrogen contains 120 megajoules (MJ) of energy. So that’s 49,008,333,333 kg of hydrogen needed to produce the same amount of energy for end-users.
Approx 50 kWh of electricity is needed to produce 1kg of green hydrogen. We can’t improve electrolysis much, but let’s be generous to hydrogen and assume we get it down to, say, 45 kWh watts per kg. The total amount of electricity required to produce sufficient hydrogen to replace that gas on a 1:1 basis is 2,205 terawatt-hours (TWh)
The total output of the entire national electricity grid of Australia, all sources, all states, all fossil fuels and all renewables, in 2020-2021, was approximately 266 terawatt-hours. Ergo, to replace the gas industry petajoule for petajoule, Australia would have to build its entire electricity grid EIGHT TIMES OVER again, just to make the hydrogen.

NO ONE is building that before 2050!

And that’s before accounting for energy for pressurization, liquification, transportation, etcetera.

Do the math. Any industry, any country, any application you like, the numbers quickly get mind-bogglingly BIG.

To transition the global steel industry, for example, which I get excited about and think should be a priority, will require something in the order of DOUBLE the entire renewables capacity on planet earth today. Ouch!

I wish it were otherwise, but despite all our efforts and ingenuities and no matter our good intentions, we can’t beat the physics.

And you don’t have to take my word for it. Listen to my interview with Dr George Crabtree, Director of the Joint Center for Energy Storage Research (JCESR) at Argonne National Laboratory. Or ask Mark Jacobsen, Professor of Civil & Environmental Engineering and Director of the Atmospheric Energy Program at Stanford University. Or ask any physicist.

IMPLICATIONS FOR THE FUTURE OF ENERGY

So, we can be sure that:

The world will be SUPPLY CONSTRAINED on hydrogen through 2050.

To have any chance of making net-zero, every country will have to:

Make tough choices about where to best apply limited supplies of hydrogen.
Prioritise end-to-end electrification over hydrogen wherever possible
Most importantly, make tough choices about what proportion of their precious renewables should be diverted to producing hydrogen

And those renewables ARE precious! Globally we are installing new renewables at a rate of hundreds of gigawatts a year. To have any hope of making net-zero, we need to be installing terawatts per year (think: a fivefold increase in the install rate) so we’ll need to allocate every terawatt just as carefully and efficiently as we can.

Otherwise, we are pretending it’s OK to divert prodigious quantities of renewables to manufacturing hydrogen instead of to the much more efficient task of direct electrification and fossil-fuel replacement, OR we are pretending it is OK to keep using steam methane reforming to produce hydrogen, both of which render achieving net-zero impossible.

Of course, some politicians and industrialists are happy pretending. But they can’t hide from the physics for long. The truth will out. The universe makes a habit of it.

DON’T WORRY, WE HAVE ALL THE TOOLS!

Luckily, what’s happening in solar and wind and batteries is so unbelievably good, and smashing so rapidly downwards on price, and the NEXT GENERATION of photovoltaics and batteries and wind-turbines will be so much better again, that we have all the tools we need to make this most challenging of all transitions.

Do we love hydrogen? Yes! Will hydrogen be part of the mix? Definitely! Is it a vital part of our future? Absolutely!

Just not a very big part.

———

** March 2024 UPDATE:- When I originally wrote this article, I left open a tiny window for clean hydrogen to play a role in long-distance trucks and ferries and long-haul aviation. That window is now shut. Developments in electrification and batteries have completely annihilated hydrogen as a commercial option for trucks and ferries (ie the inefficiencies, costs and maintenance overheads are now so ridiculously uncompetitive that no sane operator will choose it over direct electrification, and all current trials will die a slow death) and the energy and volume inefficiencies and packaging challenges rule it out of the future of long-range aviation, which most likely remains wholly tied to biofuels. I predict hydrogen will play NO serious role in the future of transportation. Still bullish on the steelmaking though :-)

———

Bruce McCabe