Eclipse risks national grids

Drivel. Totality is far to the North and lasts only a few minutes. Also the eclipse is earlyish in the morning when PV output is low anyway. The shadow of the moon moves across the earth and does not cover all places simultaneously.

Clouds drifting by have a similar effect.

Reply to
harryagain
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That's installed capacity. Only = actual capacity if it's sunny everywhere and at midday. Probably not even then

Reply to
harryagain

No it's not. The moons shadow tracks across the Earth. In this case to the North of Europe. The shadow is quite small.

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Reply to
harryagain

Reply to
harryagain

Total Solar Eclipses Total Solar Eclipses are localized and short: a.. The Moon's umbral shadow is at most 267 km across on the Earth. b.. Totality lasts at most about 7.5 minutes, with the shadow sweeping rapidly west-to-east. c.. Only observers in the umbra see a total solar eclipse. d.. Observers in the penumbra see a partial solar eclipse. e.. Everyone else sees nothing. While we often sketch the penumbra as uniform, in reality the penumbra shades gradually from the completely dark umbra out towards the edges. The reason is simple: as you move outwards away from the edge of the umbra, you will see an increasing fraction of the Sun peeking out from behind the Moon. There is a very nice Mir image of the 1999 Aug 11 eclipse shadowshowing what I mean.

Reply to
harryagain

The sudden loss and then rise of output from solar panels is a much bigger sudden drop and rise than national grids are designed to handle. Germany in particular is expecting to loose up to 35GW during tomorrow's eclipse, depending on the weather at the time, and has warned that national electricity supplies are at risk.

Reply to
Andrew Gabriel

Perhaps just as well that cloud is forecast here tomorrow then? ;-)

Chris

Reply to
Chris J Dixon

I'm sceptical because it isn't a sudden thing at all. It takes a good hour.

Bill

Reply to
Bill Wright

I was thinking more "Perhaps just as well solar electric is such a totally useless irrelevance.", or at least that's what we're always told here...

"Up to 35gw". Yep. Right. Total UK demand at the moment is 42gw. Yes, Germany has a higher population, but...

Anyway, an AA battery is "up to 35gw".

Reply to
Adrian

This is complete *BOLLOCKS* (TM). It is no different for the grid than waking up tomorrow and finding that it is cloudy. At 90% obscuration peak the sun will be about as good as on a cloudy day. They might lose

18GW from optimal peak midday output in midsummer but much less from what your would expect for early morning at the equinox.

The record amount they have ever got out of solar PV was only 24GW at midday on June 6 last year. I doubt very much that they can lose 35GW at this time of year with the sun much lower and in the early morning. There hasn't been time to install an extra 12GW since then.

An eclipse isn't especially fast unless you are comparing it to a cricket match or watching paint dry. It is about 4 hours duration from first contact to last contact. The period with maximum obscuration is fairly short but still no different to a cloud passing over the sun.

Gas fired generators should easily take up the slack. More likely it will be cloudy just to spite astronomers.

Sunny at the moment though so cross fingers for a decent show - and do remember not to look directly at the sun. This is especially important near maximum eclipse when the low light levels mean the eyes iris is wide open and the sliver of photosphere is still just as bright.

A burn on the retina doesn't hurt for at least 6 hours and is then excruciating. A few folk end up in A&E every time there is an eclipse...

Reply to
Martin Brown

Apparently the main problem will be when everybody stops watching it and goes indoors to make a cup of tea.

Reply to
Nightjar

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In particular, "The country has been the world's top PV installer for several years and still leads in terms of the overall installed capacity, that amounts to 38,359 megawatts (MW) by January 2015, ahead of China, Italy, Japan, and the United States."

It contributed 35.2 terawatt-hours of electricity in 2014, or about

6.9 percent of the country's electricity requirement.

Except at night, on cloudy days and during eclipses, when they import nuclear-generated electricity from France (rather than making it themselves; bit of hypocrisy there!) or hydro from Norway or Sweden via Denmark.

Reply to
Chris Hogg

But the sun will (or might) have returned by then, so normal power will be restored. It's the start of the outage as they all shut down that might be a problem. And anyway, as the light starts to go most people will go outside, hence power usage will drop for a while.

Reply to
Andrew

If you are only talking about solar power, yes. But, in the UK, it is having enough conventional plant on line for the expected sudden peak in demand after the event that is of greater concern.

Reply to
Nightjar

An interesting point. It's often said here that the problem with renewable energy is its variability, especially short-term, and that in order to accommodate that variability you need a lot of power stations on dispatchable stand-by ('hot spinning' is the phrase, I think), producing loads of CO2 in the process, so the amount of CO2 actually saved is much reduced, let alone the cost of having two separate power systems when one running consistently on base load, would do.

But while I can understand that argument applying to cumbersome coal-fired power stations, it seems to me gas fired turbine systems such as CCGT's, are much more flexible and can be brought in much more quickly, thus weakening that particular aspect of the argument against Renewables. You still have the additional cost of keeping two systems serviceable, of course, but that's a different argument.

Comments anyone?

Reply to
Chris Hogg

Naw people will be bored and once the peak has passed they'll be going back in for a cuppa or back to work. Light levels will still be much reduced.

This true but the change due to the eclipse is fairly slow compared to the pickup after a popular TV programme. Those can be a couple of GW in just a a few minutes.

That's what Dinorwic is for... gas can follow the slow solar loss/return without breaking into a sweat. Recent days have had gas running at about 15 GW, the evening peak rising to nearly 20 GW. So that's 5 GW "on hand" for a normal day, how much Solar PV have we got? I don't think it's that much, couple of GW? Dinorwic could almost handle that on it's own.

For the UK, other countries that have a significant amount of ther power coming from solar PV may have interesting grid balancing act to perform tommorow. An eclipse isn't like a bit of random cloud, it's darkening the whole of Europe at the same time.

Reply to
Dave Liquorice

Yes. There will be a lot of rear-enders on the roads around 9:30 tomorrow. This'll probably eclipse (sorry) and problems with the power :)

Reply to
Tim Watts

German friend tells me their solar is now almost 40GW capacity. When it reaches 50GW capacity, there will be no more government subsidies for new installations. They also have problems with too many south facing - they can't use or sell much of the peak demand, and encourage east/west facing installations now.

Reply to
Andrew Gabriel

Lying toad. Of course clouds matter.

Reply to
harryagain

Chris Hogg posted

There is also the argument that making two sets of generating capacity releases a lot more CO2 than making one.

We've had the argument here before (see for example the thread OT Penny Finally Beginning To Drop starting around 31 October 2014). No-one appears to know the answer. The anti-renewable group here simply wave the argument away as if they hadn't heard.

Reply to
Big Les Wade

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