PowerSwitch Main Page
PowerSwitch
The UK's Peak Oil Discussion Forum & Community
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Reliability of data

 
Post new topic   Reply to topic    PowerSwitch Forum Index -> Electrical, Theory and Practice
View previous topic :: View next topic  
Author Message
fuzzy



Joined: 29 Nov 2013
Posts: 595
Location: The Marches, UK

PostPosted: Mon Nov 27, 2017 2:15 am    Post subject: Reliability of data Reply with quote

I am always skeptical of IT supplied info, since you are at the mercy of unknown software and systems. At 1.10am GMT, this site:

http://clivebest.com/rgraph/Wind.html

claims we are using about 2.2 GW of solar power in the UK.

Once we see an error, why should we assume any of the other data is valid?
Back to top
View user's profile Send private message
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6217
Location: North Somerset

PostPosted: Mon Nov 27, 2017 5:27 am    Post subject: Reply with quote

I have more faith in the data on the gridwatch site, the figures generally seem to be consistent with common sense and with that which would be expected.
Glitches and errors have been known on the gridwatch site, but are usually obvious if one views the site regularly and gets a feel for what may be expected.

If I quote figures on these forums, I generally mean figures from gridwatch unless stated otherwise. If I quote a figure from any published source, but have reason to doubt the accuracy thereof then I always make this clear by use of wording such as "reported as XYZ, but which looks like a mistake to me"
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
PS_RalphW



Joined: 24 Nov 2005
Posts: 5267
Location: Cambridge

PostPosted: Mon Nov 27, 2017 7:59 am    Post subject: Reply with quote

Overnight wind was the biggest single source of power. About 9.5Gw, more than coal and gas combined.
Back to top
View user's profile Send private message
Mr. Fox



Joined: 24 Nov 2005
Posts: 491
Location: In the Dark

PostPosted: Tue Nov 28, 2017 10:58 pm    Post subject: Reply with quote

Source for the PV data is Sheffield Uni:

https://www.solar.sheffield.ac.uk/pvlive/

The Sheffield figure is only a model and based on a limited sample - seems offline, anyway.

That said, Clive Best's data doesn't tally with theirs, so I think his site is broken.

There is no UK wide PV SCADA system (nor will there be), afaik, so any figures you see will be extrapolated from installation records. Same for small wind.

Gridwatch (and others) use "Balancing Mechanism" Reports (for non-PV), which is real(ish)time grid data: https://www2.bmreports.com/bmrs/?q=eds/main

- straight from the horse's mouth, as it were.
Back to top
View user's profile Send private message
clv101
Site Admin


Joined: 24 Nov 2005
Posts: 7636

PostPosted: Tue Nov 28, 2017 11:17 pm    Post subject: Reply with quote

Mr. Fox wrote:
There is no UK wide PV SCADA system (nor will there be), afaik, so any figures you see will be extrapolated from installation records. Same for small wind.

Yeah, which is problematic as many installs are not performing as well as they might, trees grown causing shade, panels become dirty, some aspect of the system broken and not repaired...

That said, there are also a lot of PV systems that aren't on the installation record. I've had a 1.62kW system running since the spring, generated some 600kWh that no one has counted. I'm in the process of installing a 6.5kW system, similarly off the books.
_________________
PowerSwitch on Facebook | The Oil Drum | Twitter | Blog
Back to top
View user's profile Send private message Visit poster's website
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6217
Location: North Somerset

PostPosted: Wed Nov 29, 2017 1:29 am    Post subject: Reply with quote

PS_RalphW wrote:
Overnight wind was the biggest single source of power. About 9.5Gw, more than coal and gas combined.


Are you certain that it was that high, on the gridwatch site ? If so then a new record has been set.
The highest recorded wind power that I have seen is 8.94 GW, this could of course have been exceeded when I was not looking ! The chart or record on gridwatch has too low a resolution to show the difference between 8.94 and 9.5.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
vtsnowedin



Joined: 07 Jan 2011
Posts: 4281
Location: New England ,Chelsea Vermont

PostPosted: Wed Nov 29, 2017 9:54 am    Post subject: Reply with quote

clv101 wrote:
Mr. Fox wrote:
There is no UK wide PV SCADA system (nor will there be), afaik, so any figures you see will be extrapolated from installation records. Same for small wind.

Yeah, which is problematic as many installs are not performing as well as they might, trees grown causing shade, panels become dirty, some aspect of the system broken and not repaired...

That said, there are also a lot of PV systems that aren't on the installation record. I've had a 1.62kW system running since the spring, generated some 600kWh that no one has counted. I'm in the process of installing a 6.5kW system, similarly off the books.
All that uncounted renewable power will eventually show up as reduced demand for traditional sources.
Back to top
View user's profile Send private message
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6217
Location: North Somerset

PostPosted: Wed Nov 29, 2017 11:44 am    Post subject: Reply with quote

Indeed, this may be the reason that indicated demand has fallen in recent years.
All large electricity suppliers into the grid are metered in real time and the data appears on the gridwatch site.

Most PV is NOT metered in real time, the given figure is an estimate based on metering a small number of hopefully representative examples and then extrapolating. Note that the error between estimate and actuality could be positive or negative.

All large wind farms are metered in real time and the result displayed on gridwatch. Small grid connected wind turbines are not real time metered and are not included. Therefore the figure given for "wind" is CERTAIN to be LESS than the actual total production.
The degree of under reporting is open to debate, but must exist.

There is also a relatively small amount of private fossil fuel generation that is not metered in real time and therefore not reported on gridwatch. This also would show up as a reduction in indicated demand.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6217
Location: North Somerset

PostPosted: Fri Dec 01, 2017 5:02 pm    Post subject: Reply with quote

A good example of unreliable data occurred yesterday on the French gridwatch site.
At about 22-00, the indicated production from nuclear and other sources declined to a fraction of normal, as did the indicated demand.

This COULD happen in the event of some very unlikely grid failure, but in this case common sense wins !
If it HAD happened, much of France would have been blacked out. This clearly did not happen or it would have been widely reported.
Also, the indicated nuclear production recovered in an hour or two, nuclear plants do not re start that quickly.
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
fuzzy



Joined: 29 Nov 2013
Posts: 595
Location: The Marches, UK

PostPosted: Sun Dec 10, 2017 11:04 am    Post subject: Reply with quote

While I'm asking about data, anyone know how our gas storage is nowadays?
Back to top
View user's profile Send private message
adam2
Site Admin


Joined: 02 Jul 2007
Posts: 6217
Location: North Somerset

PostPosted: Sun Dec 10, 2017 1:39 pm    Post subject: Reply with quote

fuzzy wrote:
While I'm asking about data, anyone know how our gas storage is nowadays?


I have just posted about this in the long running "gas" thread. Here.

http://www.powerswitch.org.uk/forum/viewtopic.php?p=288206#288206
_________________
"Installers and owners of emergency diesels must assume that they will have to run for a week or more"
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    PowerSwitch Forum Index -> Electrical, Theory and Practice All times are GMT + 1 Hour
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group