[Discuss] Eclipses Re: Great talks last night, however...

[Robert Krawitz]

On Sun, 23 Jul 2017 00:23:26 -0400, Richard Pieri wrote:
> On 7/22/2017 8:56 PM, Robert Krawitz wrote:
>> But it's considerably more than 10% in practice, right?
>
> It depends. It's as much an ideal as Musk's asserted 90% efficiency for
> Tesla and Powerwall when in reality Tesla and other EV owners see as low
> as 50% with new cells. And as noted previously, that figure drops as
> batteries wear.

"As low as" 50% is a whole lot more than 10%.

>> You still need storage for those blackouts (albeit less), right?
>
> Yes, but with blackout windows of ~70 minutes you can effectively use
> supercapacitors which in principle should be superior to chemical
> batteries for short term storage.

Supercaps have their own problems...not very dense compared to
batteries, for example.  And a lot more expensive for the same
storage.

>> The author is quite clear that he simply doesn't see this as being
>> plausible any time soon.  And no doubt batteries will improve along
>> the way.
>
> I do doubt it. Li-ion appears to be it, the pinnacle of commercial
> battery technology. Li-air has potential but it needs a breakthrough to
> make it commercially viable and you can't count on breakthroughs.
> Likewise Li-sulfur which has wear and volatility (read: safety) issues.
> And, of course, batteries aren't renewable.

The pinnacle at present, maybe.  While it's true we can't count on
particular breakthroughs, it's pretty clear we can count on
breakthroughs of some kind happening.  There may be improvements in
Li-ion that improve lifetime, charge density, etc.  Hopefully we'll
find something based on non-lithium chemistry, since lithium's
scarce.  And not renewable?  Since when?  Extract the lithium and use
it to fabricate new batteries.

Interesting that we can't count on breakthroughs in battery
technology but we can in space...
-- 
Robert Krawitz                                     <rlk at alum.mit.edu>

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