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Comment by nephrite | Hacker News Reader

I really don't like that the hydrogen made in process is considered waste and is escaping. We sure have a lot of water on planet but if the technology will become mainstream and we will just throw the hydrogen away it will become a huge problem.

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Orders of magnitude are important. There are 326,000,000 cubic miles of water in the oceans. 1 cubic mile = 5280 * 5280 * 5280 * 7.48 gallons/cubic foot * 8.35 pounds per gallon. Aka ~ 3 * 10^ 21 pounds and 21 is one of those exponents that are hard to wrap your head around. By comparison worldwide aluminum production is only 1.1 * 10 ^ 7 pounds. Further, only the fraction of hydrogen that reaches space is lost to space making this a non issue.

It seems like we're a very long way away from it being a practical problem. And if it ever becomes an issue it doesn't sound like it will be very hard to overcome. After all burning this hydrogen would release even more energy and some water, although it would require a source of oxygen.

If anything I'd be more worried about the large scale effects of massive amounts of aluminum hydroxide being released in the environment.

At least aluminum hydroxide is solid, so it's easy to collect. Hydrogen is gas though.

Hydrogen in low concentrations isn't dangerous and it's gonna be slowly bonded into water again whenever there is a flame or lightning strike.

Sunlight is also important for these reactions. There is quite a bit of ozone which combines with hydrogen to become oxygen + water.

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