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

[Richard Pieri]

On 7/23/2017 12:29 PM, grg wrote:
> OK, so you're saying that instead of single-digit percentages, there are
> real-world battery installations which get 75%-80% charge/discharge
> efficiency; meaning that if using them we'd only need to make 20%-25% more
> solar power, not 1000% more, to compensate for the loss in batteries.

When new under good conditions. Those numbers drop as conditions change
(extremes of heat and cold) and batteries wear out.

> http://www.sandia.gov/ess/docs/pr_conferences/2014/Friday/Session10/04_Vishwanathan_V_Powin_Dispatchable_Battery.pdf

And what are their numbers after 3, 4 or 5 years?


> But somehow, 99.99% of people and corn and cows (not counting that
> unfortunate animal in the movie Twister) have managed to survive there.
> I'm betting solar panels will have a similar tornado survival rate, unless
> we decide to install them only at trailer parks.

That's because people and livestock can seek shelter in foul weather,
and plants grow and heal or at the least can be plowed under and the
land replanted. None of these describe thousands of square kilometers of
solar panels.

> One standard solution to weather exposure would be to house them below the
> frost line, which is only 2'-3' deep in Kansas:
>     https://www.ngs.noaa.gov/PUBS_LIB/GeodeticBMs/#figure13
> You'll get a moderate temperature all year round.

Then you're insulating them which means they'll be that much hotter when
charging during warm months. See previous about heat being bad for
batteries.

> Luckily, the 10,000 km^2 solar+battery farm will still meet the entire US's
> energy needs even if you replace the batteries more frequently.

Oh, yes. Replace unsustainable batteries more frequently. That's exactly
what Musk wants because guess what? He sells batteries. Can you smell
the marketing yet?


> Again, if you do the math, it's exactly pi.  The equator is a circle; the
> sunlight incident on it is its shadow at this point in space, which is a
> line that is the diameter of Earth - on that line every point is always at
> "noon", and it would collect all the light the equator sees.  Will ascii
> art help?

You're ignoring the atmosphere.

-- 
Rich P.