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Comment by walrus01

2 days ago

Over many years, I've yet to hear of an ocean based power generating system that comes anywhere near the $ per kWh cost produced by just covering some less-useful land in ground mount photovoltaics.

Private, entirely for profit companies, have recently answered large government tenders in the middle east to sell power at the equivalent of $0.05 USD per kWh. They are fairly confident that they can make a profit doing this, even with the cost to incur the long term debt to privately build a massive solar power plant.

The cumulative amount of solar power being produced within Germany right now is a good example of its practical use in a less sunny climate.

In terms of placing things in the ocean, hiring the sort of offshore work vessel with a built-in crane can go and place or remove multi ton apparatus is very costly. Maritime construction for things like laying coastal submarine cable, building piers and docks and marinas, setting and maintaining marker buoys isn't cheap.

Laying and maintaining HV AC or DC submarine cables in salt water is also particularly known to be expensive. Hiring a 36'-42' aluminum landing craft for coastal construction projects, with fuel and crew can be easily $500 an hour.

Labor and vehicle costs are greatly increased compared to doing things on dry land.

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walrus01

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542354234235  2 days ago

I used to think the same way, “just use cheaper solar” but I have come around to see the value. Doing science and engineering projects to explore new or different alternatives is valuable. We might find something surprising.

Having different types of power generation provides redundancy. The wind still blows at night, the tide still comes in and out when its cloudy, etc. Grid storage is nowhere near a solved problem, so something like tidal could prove less expensive than storage or overbuilding alternatives to overcome their variability problems. Even if it doesn’t end up being widely useful, it could still end up finding a use in more niche applications.

Finally, it can and will improve. 30 years ago, solar was not price competitive and decades of development and iterative improvements have changed that. We should keep developing alternatives to see their full potential.

gleenn  2 days ago

I think the charm for a cloudy place like Scotland is that a system like this is unaffected by poor light supply. Your photovoltaics aren't going to fair nearly so well there hence this solution.

Cthulhu_  2 days ago

> covering some less-useful land in ground mount photovoltaics.

Doesn't even need to be less-useful land (especially in western Europe, ground is becoming a scarce resource), put PV on flat rooves or add them over open car parks. Also helps alleviate pressure on the overstressed energy grid by generating and using power more locally.

But, local power is (overall) a lot more costly than major centralized power generation projects, like a wind farm or what have you.

  • mrspuratic  2 days ago

    Ironically, renewables tend to put a different kind of stress on the grid: frequency. In Ireland the grid can't handle windy days, so there are ROCOF issues and "dispatch down" events which means clean energy is lost.