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Comment by squaredot | Hacker News Reader

When the subject arise I usually point at the following interesting article

https://ethz.ch/en/news-and-events/eth-news/news/2021/11/hyd...

That has nothing to do with the subject at hand. You cannot charge a battery at 100% efficiency, especially from the source electricity. People are simply creating an apples-to-oranges comparison here. You're just distracting from this fact.

There are of course losses when charging a battery, but they are orders of magnitude larger when talking about the creation of hydrogen versus the charging of a battery. Hydrogen simply isn't a good idea for a number of reasons, and the energy needed to separate it from water is just one of them.

Quoting "apples to oranges" here ignores the massive inefficiency in other stages of the process of storing and distribution of hydrogen, which is difficult and expensive to do. The distribution of electricity is much more efficient and cheaper.

Factually no. There is no straightforward method of taking energy from renewable sources and getting it to a charging station. In reality, this is one of the hardest parts of green energy. You simply have to ask the question, "what happens when the wind is not blowing or the sun is not shining?"

In fact, this is a total inversion of reality, bordering on science denial. The process of making and storing hydrogen is a straightforward process. It is trying to this with only electricity that is very hard.

> "what happens when the wind is not blowing or the sun is not shining?"

You ramp up your hydro output and spread out and postpone the load. People have adapted to doing dishes and laundry when electricity is cheap, this is not different.

Hydro is energy storage. It incurs losses. It also requires you to have hydropower.

> Which energy storage losses am I ignoring?

Pumped hydro is energy storage that you have to put energy into to push water uphill. And yes it has losses, 25% losses round trip.

If you have a hydroelectric damn however, you increase the flow when the sun doesn't shine or the wind doesn't blow and curtail it otherwise.

> It also requires you to have hydropower.

It's true. Just as wind turbines needs good wind, solar needs ample sunlight, and hydrogen proposals need large underground caverns.

If you are relying on wind and solar, then you will need energy storage. You will have to take the losses into account. You’ve already admitted this partially by acknowledging 25% losses with pumped hydro. But not everywhere has pumped hydro, nor hydropower at the scale needed.

The point is that hydrogen gives you nearly lossless energy storage. This is why simplistic accounts of efficiency are simply wrong. People are ignoring energy storage losses on the BEV side, but always bring up the full cycle losses on the hydrogen side. This is an apples-to-oranges comparison, and gives you an invalid conclusion.

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