science

18523 readers

566 users here now

A community to post scientific articles, news, and civil discussion.

rule #1: be kind

founded 2 years ago

MODERATORS

[email protected]

191

A German Experiment Proved That Simple Concrete Spheres Make Fantastic Batteries. Now, California Plans To Submerge A 9-Meter Diameter Sphere In The Ocean And Is Already Planning Versions Of 30 Meters (farmingdale-observer.com)

submitted 3 days ago by [email protected] to c/[email protected]

79 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 9 points 3 days ago (12 children)

... a sphere nine metres in diameter and weighing 400 tonnes will be submerged off the coast of California at a depth of 500 to 600 metres. It will have a storage capacity of 0.4 megawatt hours (400 kWh) ...

i will try a rough calculations : suppose we can have concrete at $100 per ton, then it's a minimum investment of $40,000. Also suppose electricity is stored with a large added value of 10 cents per kilowatt hour, so, for every cycle a rough gain of $40. By these numbers, 1,000 cycles would pay for the concrete ... so, it may look good considering they plan a life of about 50 years for such devices.
On the other hand if competitive battery storage cost only one cents per kilowatt hour (temporary in and out storage) and if concrete and fabrication goes up 10 times to $1,000 per ton then it is not economically viable anymore.

A good calculation of profitability would need to take into account the less than 100% energy efficiency of batteries cycling and of hydraulic energy cycling, ... and so many more parameters which have to be studied.

[–] [email protected] 7 points 3 days ago (10 children)

They describe these as giant concrete spheres, but there are (obviously) pumps and turbines involved too, and that those are aimed at a 20-year partial part-replacement lifespan. There's no indication as to how much these pumps/turbines will cost but I'm gonna guess probably more than the cost of the concrete since it's relatively cheap in comparison, and that's before you consider that the major wearing components (which is to say, the expensive stuff) will have to be replaced twice within the intended lifespan. And that's not accounting for things that break and need to be replaced, inside of a giant concrete sphere on the bottom of the ocean where maintenance will be absurdly expensive. Needless to say I'm pretty skeptical of the economic viability of this project. I'd be happy to be proven wrong, but I'm not holding my breath.

[–] [email protected] 0 points 3 days ago (1 children)

I'd assume they'd put these pretty close to the surface, lowers the water pressure and makes it more accessible

[–] [email protected] 4 points 3 days ago

If you read the article it includes this line:

The idea is relatively simple: hollow concrete spheres are installed at a depth of several hundred metres.

The pressure is needed to drive the turbine, cause just gently-flowing water isn't going to cut it.

load more comments (8 replies)

load more comments (9 replies)