1. Skip to navigation
  2. Skip to content
  3. Skip to sidebar

BIG Batteries

Home Forums Archive Infrastructure BIG Batteries

This topic contains 6 replies, has 5 voices, and was last updated by Profile photo of Melllvar Melllvar 5 years, 8 months ago.

Viewing 7 posts - 1 through 7 (of 7 total)
  • Author
  • #727
    Profile photo of

    Hello all,

    i’m not here to discuss Seasteading. I’m studying ocean acidification and it occured to me that a battery works by electrons passing through a terminal connected at either end to an acid and an alkali (right?). I’m not any kind of engineer and I really don’t know how batteries work, but seawater is slightly more acidic at the surface than it is at depth. Although the difference is slight couldn’t one use this potential to generate electricity? Seawater pH ranges from about 8.1 to 7.8 at present – does one end of the terminal have to be acidic or just more acidic than the other end? If it doesn’t need to be acidic then I thought of it first OK?!!! The potential of an enormous ocean battery that generates ridiculously large amounts of electricity while at the same time reducing surface acidification (and increasing ocean CO2 uptake) might be quite a nice thing to invent. It can’t work because it’s too nice an idea, but I’d like someone to explain to me why it can’t work.


    Profile photo of CrosiarCM

    Do you have any links showing the difference in acidity?

    You may get what you want, but will you want what you get?

    Profile photo of

    No sorry I don’t. Most of my information comes from scientific journals. There might be some mention of it in the Royal Society article on Ocean Acidification which I think you can get online. Otherwise there’s a good article in Nature – Caldeira and Wickett (2003) and in more detail by Orr et al (2008). If you’re very interested I could forward you the articles. Could it work?

    Profile photo of Patri

    That sounds like a very small difference that would require moving water over a long distance. Much like OTEC, except with a smaller gradient. OTEC is already problematic (requires huge economies of scale to be efficient), salinity gradients sound worse.

    Also, I thought that there weren’t good ways of tapping salinity gradients? Otherwise they’d use the gradient where freshwater meets seawater at the mouth of a river to generate power.

    Profile photo of

    Like I say I’m not an engineer and I really don’t know what I’m talking about, it was just an idea. Couldn’t you just have insulated wires running from an area of high pH to an area of low pH to carry the charge? OK it would be a very small charge, but if all you needed was basically a wire then you could do this many hundreds of times to create a significant amount of electricity. I’ve got a feeling that I’ve just revealed how dumb I am….

    Profile photo of

    I have a feeling there will be very high resistance across a longer distance of ocean water (from the surface to somewhere deeper, for instance). This is probably bad for the workings of a battery.

    Perhaps if you used electrodes with different potential close to one another in the water this would work. But chances are the electrodes will decay faster than is economical and you would have to replace them too often. This will be sort of like continously importing disposable batteries, which can´t possibly make any sense.

    I´m no electro engineer though so all the above could be wrong…

    Profile photo of Melllvar

    Saw this bumped thread and had some brief comments…

    Patri wrote:

    Also, I thought that there weren’t good ways of tapping salinity gradients? Otherwise they’d use the gradient where freshwater meets seawater at the mouth of a river to generate power.

    This is actually being done, it’s called osmotic power.


    In theory, you could also make a giant saltwater battery by electrolysising a giant pool of saltwater to store energy and then reversing the process to get the energy back. It would be highly inefficient, and I wouldn’t recommend it, but you’d have one gigantic and cheap battery.

Viewing 7 posts - 1 through 7 (of 7 total)

The forum ‘Infrastructure’ is closed to new topics and replies.

Posted on at


Written by