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Meeting 2050 emissions goals requires the rapid phase-down of fossil fuels. Much of this can be accomplished through direct electrification. For example, fossil-fuel-burning passenger vehicles and furnaces can be replaced with electric vehicles and heat pumps. As we electrify end-uses, we must also replace coal, oil, and natural gas power plants with wind farms and solar arrays. And we need to upgrade our electric infrastructure—transmission lines, battery storage facilities, and vehicle charging stations—to accommodate increased demand and variable renewable generation.
Direct electrification can displace more than 70% of current fossil fuel use. But full decarbonization will require additional tools. “Hard-to-abate” sectors include long-haul aviation and shipping, which need portable, energy-dense fuels. They also include seasonal energy storage, for which batteries are likely to remain prohibitively expensive. In addition, we’ll need to find substitutes for fossil-fuel-based industrial feedstocks. In all these sectors, hydrogen and its derivatives will play an important role.
Hydrogen is already widely used in fertilizer production, oil refining, and the smelting of iron and aluminum ore. About 120 million tons of hydrogen are produced annually, almost all using fossil fuels. According to the International Energy Agency (IEA), in 2021, hydrogen production was responsible for 830 million tons of CO2 emissions—about 2.2% of the global total.
Decarbonizing hard-to-abate sectors with hydrogen involves the same broad steps as direct electrification. We’ll need to substitute hydrogen for fossil fuel end-uses, replacing, for example, fossil-fuel jet engines with ones that burn hydrogen-derived fuels. We’ll need to build the necessary storage and distribution infrastructure. And, of course, we’ll need to scale up production while reducing emissions.
Two general pathways have been proposed to meet the growing…
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6 Comments
Solar and wind are cheap enough that it may be cost-effective to over build them and use the excess to produce Hydrogen via electrolysis and store it for when solar/ wind aren't sufficient.
It would be interesting for the article to say a lot more about the cost and details of "densified" forms of hydrogen as fuel e.g. NH3. for aviation fuel. At an impractical 700 bar = roughly 10KPSI, a huge pressure, the volumetric energy equates to 1/6 of that of gasoline. Makes one wonder about fuel cells in cars. What is the energy equivalent volume in that application? This article amounts to a teaser with a big gap in the middle. Can any of you readers speak to the above practicle matters?
There's way more to be said about hydrogen than I could cover in one article! I'm planning a follow up on hydrogen for home heating. My understanding is that direct electrification is winning in the light vehicle sector. The technologies to transport dense hydrogen in cars (either 10KPSI tanks or cryogenic systems) add both weight and expense, which make hydrogen vehicles less competitive. The refueling infrastructure is another challenge. Electric charging is easier to scale and still not keeping up with demand. I'd be interested in others thoughts on these issues as well.
If you capture carbon dioxide out of the atmosphere, and synthesize it with hydrogen to make hydrocarbons, the resulting fuel is carbon neutral. Since we already have a well-developed distribution network for hydrocarbons I see this as being much more promising than using hydrogen directly.
There are certain applications where energy density is critical -- aviation, as a prime example. There is no technology on the horizon to replace the use of hydrocarbons in aviation. Replacing jet fuel with net-zero synthetic hydrocarbons is the only viable solution.
Both hydrogen production and carbon extraction lend themselves to off-peak production, things to do when the production of the grid exceeds demand.
The problem with using "free" energy during times of overproduction is that you still have all of the expense of the hydrogen infrastructure to support. Once you've built a plant, pipelines, and all of the extras, you need to run them at full capacity to even approach the LCOE of solar or wind energy. And that's just at the plant itself. Pipelines to carry hydrogen would have to be built from scratch with untested technology, whereas the electric grid is already up and running. Yes, it will require massive upgrades but those are already understood and planned as a part of the standard maintenance/upgrading process. Yes, synthetic fuels would obviate the need for a hydrogen distribution system, but that's yet another plant to build with its own costs and efficiency penalties. With the possible exception of aviation fuel, I have yet to see a use case where hydrogen even comes close on a delivered cost basis. To me, hydrogen seems to be a canard used by the legacy fossil fuel companies in an attempt to show their shareholders that they can remain relevant in a zero carbon future.
I wouldn't ever ship the hydrogen anywhere, I would produce it at the same location I produce hydrocarbons. Probably do CO2 capture at the same location, although CO2 is more shippable. The input is energy, air and water, the output is hydrocarbons.
They could then be distributed using the existing well-developed distribution network for hydrocarbons.
Any place that currently has bitcoin mining operations would probably be a good candidate for a plant like this.
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