
Solar eclipse poses energy challenge - GotAnyMegadeth
http://www.bbc.co.uk/news/business-31951768
======
sxcurry
On the surface, this seems really silly. What happens on a cloudy day? Don't
the utilities need to deal with power output drops all the time?

~~~
tjradcliffe
They do, but rarely across the whole grid at once. This event is like it
becoming extremely cloudy everywhere for about five minutes, followed by a
return to normal conditions. That's a fairly large transient, so it isn't
really "solar power is variable" that's the story, but "solar eclipses produce
an unusually large transient in solar output".

The same is true of wind power, which in some areas (the province of Alberta,
in Canada, for example) wind resources are concentrated in a small geographic
area, so when the wind stops blowing all the wind power drops off the grid.
Alberta has limited their total wind capacity to 3% of average demand to
prevent this from creating instabilities.

Distributed storage is going to be a significant part of our renewable future,
which will mitigate these problems, but for the moment the growth of solar and
wind capacity has outstripped storage capacity, so we can expect there will be
a few unfortunate events along the way (which will stimulate NIMBYs to
denounce the entire technological sector, quite likely.)

~~~
mikeash
It's not _that_ fast. In London, for example, the eclipse starts at 8:25AM,
and doesn't reach its maximum until over an hour later, at 9:31AM. It then
takes another hour and change before it finishes at 10:41AM.

It is unusual that this event takes place nearly simultaneously over a whole
country-sized area, but it's not a five-minute thing.

------
femto113
Um, isn't there an "eclipse" for roughly 12 hours every day?

~~~
mikeash
Yes, and that one corresponds nicely with reduced demand for electricity. This
one doesn't.

~~~
femto113
According to the EIA [1] Peak demand (in New England, which I imagine is
similar to the UK) appears to be around 7PM, which is well past the time
significant solar production is occurring.

[1]
[http://www.eia.gov/todayinenergy/detail.cfm?id=830](http://www.eia.gov/todayinenergy/detail.cfm?id=830)

~~~
mikeash
The timing certainly could be worse, but this eclipse is right at the "morning
ramp" period, where demand is substantially higher than during that big
eclipse we get every night.

