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Comment by _aavaa_ | Hacker News Reader

It is not the most logical replacement.

It isn’t the the one with fewest infrastructure changes (that would be biodiesel).

And it is the result of stuck about things in terms of the past: we used to power cars by pumping molecules into it, therefore we need another molecule.

Most of our green electricity will start as electricity. So it makes more sense to keep it as that and pump it directly into the car.

Given the choice, why would people still want to have to take their car to a pump when they can simply charge it at home or at work as much as possible?

If my cellphone lasted 5 days without a charge but needed me to go to a special charging station, I would never buy it. I just charge it overnight, or at work, and forget about it.

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Biofuels aren't really a solution.

The problem with electricity is that you can't easily store it. And the only way to do so at large scale will be converting it to molecules. That implies hydrogen.

As a result, green electricity just means a nearly infinite supply of green hydrogen at the same level of cost. That implies nearly free hydrogen for any purpose.

Economically, that all leads to the hydrogen car as the future. You avoid both the weaknesses of ICE cars and BEVs.

This sounds logical, until you find out that the only viable way (make H2 from electrolysis) is wildly inefficient (75% efficiënt), then compressing/chilling it for transport is only (90%) efficiënt, then converting it to electricity with a fuel cell (max 60% efficiënt), followed by powering an electric motor (95% efficiency).

This adds up to: 0.750.90.6*0.95=38% efficiency.

With an electric battery car. Its about 75-80% efficiënt in the whole chain. That means you need twice as many wind turbines to run the same amount of vehicle miles. The math just doesnt hold up.

So unless we cannot produce enough batteries or cannot make the grid stronger. Which both are possibilities. Hydrogen cars will probably be a dream. At this point it just doesnt make sense.

Electrolysis is theoretically up to 100% efficient. So are fuel cells. The whole process is an electrochemical system not much different than what batteries are.

You're reading too much pro-BEV propaganda. They're just spreading FUD and trying to stop people from realizing there are alternatives.

That’s great, but in the real world we care about the actual efficiency.

It is not FUD or propaganda to say that the fuel cell cars you can buy today (or in the next 10 years) are not even close to 100% efficient. Nor is their round trip efficiency better than BEV. Nor or either of those numbers likely to change over that period.

If you cared about actual efficiency, you'd be skeptical of BEVs today. There's no straightforward of powering them directly with renewable energy. You will need vast amounts of energy storage to make that work. That will not be all that efficient. And that's after you accept the huge upfront cost of the batteries and all the problems they entail.

Meanwhile, no one is looking at compromise solutions. Something like a PHEV or even a plug-in FCEV would solve a lot of these complaints right away. There are ways around these issues even in the real world.

Finally, it's not like 10 years is that long in the car industry. If FCEVs end up matching BEVs in efficiency in 10 years, that's means we're pretty much at the verge of FCEVs taking over.

> that implies nearly free hydrogen for any purpose.

Now this is propaganda.

It's a simple extrapolation of the cost reduction in wind and solar energy. If you have an issue with that, then you are basically denying that wind and solar energy have become very cheap.

Don't try to argue with this guy. He is in every thread about battery claiming hydrogen is the best thing of all time. He has fully bought in to the hydrogen propaganda and doesn't care that the real world doesn't agree with him.

I’m well aware. My comments aren’t for him, they’re for everyone else who is reading them.

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