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by mrpopo 1615 days ago
Hydrogen is an extremely inefficient energy storage medium. We don't have massive amounts of energy to just waste away in an inefficient system. If we did, green hydrogen would have been chewing away at current hydrogen production for industrial usage (95% gray hydrogen).

You're of course free to believe that countries will build 3 times the capacity of their energy production to compensate for that inefficiency.
2 comments
mrpopo 1615 days ago
To give an idea of the order of magnitude of inefficiency :

* Currently a grid => hydrogen => grid round trip is 40-45% efficient.

* A grid => battery => grid round trip is 90-95% efficient.

You can recover 2x more energy by NOT using hydrogen. There is no competition. Unless the lost energy from green hydrogen production can be recovered somehow (co-generation)...

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natmaka 1615 days ago
Green hydrogen is produced thanks to electricity produced by renewables (wind, solar...) when it is useless (not immediately consumed). It's a "use it or lose it" situation: using it, even at a loss, seems sound.

Many applications (transportation, industry...) can use it as such, without any way from hydrogen to electricity, and more and more probably will.

There are surprising new ways (offering an impressive efficiency), such as: https://www.slb.com/newsroom/press-release/2021/pr-2021-1118...

At a glance: https://www.energy.gov/eere/fuelcells/hydrogen-production-el...

In-depth take: https://assets.siemens-energy.com/siemens/assets/api/uuid:53...

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marmarama 1615 days ago
I have no doubt that batteries will also form part of the grid energy storage solution. But they don't scale as well as hydrogen and have higher maintenance costs and replacement rates.
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marmarama 1615 days ago
Given how cheap renewables are becoming, yes, countries will absolutely build overcapacity.

But we won't need 3 times the amount - hydrogen will only be used to balance the grid. Most grid energy will come direct from renewables. Most of Europe would only need about 20 days' worth of hydrogen as insurance against a lack of wind or sun.

Green hydrogen has only become viable to replace hydrogen-from-fossils within the last few years as the cost of renewable energy has plummeted. That drop in renewable energy costs is what has changed recently and what has taken so many people by surprise.

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