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Comment by Melatonic | Hacker News Reader

Great idea but then again we come back to the problem of getting that power back to land. I imagine ocean currents complicate linking these things together or with big cables back to land - not to mention big storms. I do really like the idea of fish gathering below the platform - multiuse stuff is always great. We could probably also do some hydropower while were at it!

Best use case for something like this seems like for powering remote outposts and islands - land is at a premium at these places often plus you probably do not want to be clearing large areas of uniquely biodiverse land for power delivery. Some giant ones off the coast of Fiji could be a cool one for sure!

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Actually, you can manufacture ammonia from just water, air, and electricity. And ammonia not only has great uses (right now we burn a huge ammount of NatGas to make it) in agriculture, but it's quite energy/space efficient for shipping. We already ship quite a bit of liquified ammonia (<200 psi at >100F). If you have a lot of "free" energy in the ocean it makes sense to make/store/ship ammonia on the spot.

This of course also enables storage for delivery of power at night.

I think there is some physical-chemical development work left to do for maximally efficient commodity-grade solid-state fuel cells that work with ammonia and air, but it is eminently doable today. In the meantime, you can burn ammonia in combined-cycle turbines where NG is burned now.

Thanks, with solar and wind there do seem many times when there is a surplus of energy. I'm thinking somethings like water cracking to H, Aluminium smelting or Steel Furnaces could be done with such supluses but Ammonia sounds like a good one for the list too.

All of it will happen at the same time, different places.

I would imagine the problem for offshore solar farms wouldn't be bigger as for offshore windmills? That is a relatively expensive, but also not that difficult problem today? What did I miss?

Waves.

Are you saying that waves don't exist around offshore wind farms?

Waves will tend to destroy floating offshore solar farms. Wind farms are less affected because their cross-sectional area near the water surface is small relative to their mass.

But if the panels were in a semi-flexible frame with underwater floats, the waves could be made to mostly run under them.

> ocean currents complicate linking these things together or with big cables back to land

They would be connected by cables to the ocean floor (depends on depth I presume). But the currents shouldn't be an issue. Storms unless there is debris should also be fine (but I don't know what ocean weather is like).

Cables back to land are indeed an issue, especially with high energy. Maybe we'll come up with efficient energy guns, or create fuel on said platforms (hydrogen?).

"Maybe we'll come up with efficient energy guns"

Very likely not. Creating fuel seems more practical, but anchoring floating objects is a known problem as well.

30 ft (10 m) waves on a regular basis would not be unusual

Presumably, that also affects cables for offshore wind farms, and yet we routinely build those in seas that can get rough.

A big enough farm can also be a focused microwave phased array antenna, beaming power to any point overhead. Or even multiple points, given more than one frequency.

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