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Comment by mlindner | Hacker News Reader

> One thing opposition to any chemical electricity storage (hydrogen and other fuels) doesn't answer is: _how to transfer electricity across distances?_

For some countries this isn't even a problem so it doesn't need to be talked about. For example the amount of reusable energy available in the US covers all the needs in most areas.

Also you need to compare the reduced efficiency of building the renewable energy locally versus the energy lost in transporting that hydrogen and creation and use of the hydrogen. Creating the hydrogen is an especially inefficient process for example.

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And the rest of the world? And when extra energy is needed because of a cold/heat-wave, new project, or just an event in a forest?

These scenarios, both large and small, are covered currently by fossil fuels, and are not answered by permanent grid solutions like HVDC.

The generation price of solar energy is ~$0.02/kwh. Even with 33% overall efficiency hydrogen could be very competitive at $0.06/kwh electricity. , But overall efficiency is a red-herring. The important thing is COST. With solar, the cost of energy itself is the smallest part - providing it at the desired time and place are the more expensive parts.

Fossil fuels are very inefficient, yet for hundreds of years they have been a cheap option (and thus widespread). The same argument applies to hydrogen - if it's cheaper, in terms of money, time and pollution, efficiency doesn't matter a bit.

> The generation price of solar energy is ~$0.02/kwh. Even with 33% overall efficiency hydrogen could be very competitive at $0.06/kwh electricity. , But overall efficiency is a red-herring. The important thing is COST. With solar, the cost of energy itself is the smallest part - providing it at the desired time and place are the more expensive parts.

I'm not sure what you're saying here. Hydrogen produced with green energy necessarily also includes the price of that green energy. So hydrogen produced with solar has a price floor of the solar energy with all the inefficiencies of hydrogen electrolysis and use of hydrogen in a fuel cell on top of it.

It's very simple - there is a need for a dispatchable and transferrable form of energy. So far, this need has been fulfilled by fossil fuels, and if arguments against P2G solutions prevail, will probably continue for a long time.

But at least we will be physically efficient.

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