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Doc_N

Kontiki wrote: »

This is a website that can predict how much solar power you can generate at your location Performance of Grid-connected PV It is reasonably simple to use, you can select your location from the map, it allows you to put in the direction of your roof & the pitch. The table it produces will show the daily/monthly production also it shows graphs showing things such as the path of the sun in relation to your location. I already posted a couple of other sites in this thread to sites which can give you the payback any system can achieve.

We are in North Wales & had our 3.9 kW system installed mid November, output varies between 0.1 to 6.5 kW. Today it looks like it will be nearer to the 0.1 if we are lucky. Since installation it has done 78.6 kW

Thanks - I'd forgotten all about that, and it's a very useful site. I'd been a bit concerned about the sharp drop-off in performance lately, but it's almost exactly in line with the predicted figures shown.

furndire

slacky555 wrote: »

It's a point I would like you to expand on please?

I can't really tell you about in the morning (tend not to get up very early in winter), but I noticed it more on summer nights. It was very light outside say 7 - 8 pm, but I wasn't producing electricity.
I think the companies must take this into account when predicting what the yearly amount will be, as we are pretty much on target. However we have our own panels, and its the FiTs that are important to me, but if you are on the "free" panels, you will be disappointed that they stop working as soon as they do.
Orientation of the house makes a difference as well as to when they start producing i.e. the more easterly you are, but against that if you are SE, they stop earlier than if you are SW.
I wish I could explain things better in writing, but I hope you get the general idea.

As an example this month, 15 days, we have produced 60 Kw of electricity - 11 of those were on one day only and 8 on another. Some days have produced nothing. At the moment approx midday, dull raining, we are producing between 115, and 125 per hour so rougly 0.5 KW over a 5 hr period (if we are lucky). (3.96 system)

Please be really careful with that Isis contract it sounds as though you will realistically get very little in winter savings (when you need them most), and will be paying out to them. Its very loaded against you. They sound like they are trying to cover the cost of a future invertor failing, as there is very little else that needs maintainance.

slacky555

one more quick question which i cant find the answer to is:

I know the FIT's are index linked is this RPI and if so if for a current install the payment is 41.3p at what point does this start to increase?? montly as per when the new figures are out or at the same time as the FIT payment is made or yearly?

zeupater

Kontiki wrote: »

This is a website that can predict how much solar power you can generate at your location Performance of Grid-connected PV It is reasonably simple to use, you can select your location from the map, it allows you to put in the direction of your roof & the pitch. The table it produces will show the daily/monthly production also it shows graphs showing things such as the path of the sun in relation to your location. I already posted a couple of other sites in this thread to sites which can give you the payback any system can achieve.

We are in North Wales & had our 3.9 kW system installed mid November, output varies between 0.1 to 6.5 kW. Today it looks like it will be nearer to the 0.1 if we are lucky. Since installation it has done 78.6 kW

Hi Kontiki

It's probably better to use the PVGIS v4 database as it uses an updated data model.

v3 to v4 changes explained here - http://re.jrc.ec.europa.eu/pvgis/PVGIS_new_features.html
Link to PVGIS-4 .... http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php

Regards
Z

JenR8

Can anyone tell me if TV reception (Or mobile phones) is affected by solar panels on your roof? Our aerial is in the roof space.

Kontiki

Hi zeupater, tried the website using the updated PVGIS v4 database & it gave 10 kW less (2830 kW to 2820 kW) on the yearly total so it isn't anything significant. The installer gave me the figure of approx. yearly yield of 2930 kW derived from using the SunnyBoy software (I believe they use data from the Leeds monitoring station). He said he would be surprised if it wasn't above 3000 kWs, as all the other installations had produced better than the predicted figures.

There is nothing like real world data though, I calculated my November figures using the daily rate x 14 (the system was installed on the 16th Nov) this gave a predicted figure of 34.7 (actual 36.9) Decembers figures predicted 44.5 (this is the whole monthly total) actual 40.6 (so with another 2 weeks to go to produce 4 kW :T ) The predicted data is from the PV Performance website.

slacky555

Another great site with real data.

http://www.sprid.net/page4.htm

I can't seem to find anyone with charts showing average monthly generated electric V average monthly saved/used of what is generated.

Or do most think it's around 1/3 is used of what's generated?

zeupater

Kontiki wrote: »

Hi zeupater, tried the website using the updated PVGIS v4 database & it gave 10 kW less (2830 kW to 2820 kW) on the yearly total so it isn't anything significant. The installer gave me the figure of approx. yearly yield of 2930 kW derived from using the SunnyBoy software (I believe they use data from the Leeds monitoring station). He said he would be surprised if it wasn't above 3000 kWs, as all the other installations had produced better than the predicted figures.

There is nothing like real world data though, I calculated my November figures using the daily rate x 14 (the system was installed on the 16th Nov) this gave a predicted figure of 34.7 (actual 36.9) Decembers figures predicted 44.5 (this is the whole monthly total) actual 40.6 (so with another 2 weeks to go to produce 4 kW :T ) The predicted data is from the PV Performance website.

Hi

Looking at the net change map between the two datasets it looks like there has been a general reduction in estimated insolation in and around mountainous areas, so I'm not surprised that being in North Wales there is a reduction in anticipated output. (link (See Fig.1) - http://re.jrc.ec.europa.eu/pvgis/PVGIS_new_features.html)

The increase in output over prediction for your array could be due to this ...... http://www.metoffice.gov.uk/climate/uk/anomacts/2010/11/2010_11_Sunshine_Anomaly_1971-2000.gif .... November seems to have been particularly sunny in North Wales when compared to average ..

HTH
Z

Cardew

slacky555 wrote: »

I can't seem to find anyone with charts showing average monthly generated electric V average monthly saved/used of what is generated.

Or do most think it's around 1/3 is used of what's generated?

Unless you have an export meter, it is not possible to calculate how much of the generated output you use in the house.

As far as I am aware just two people on MSE have given figures for their 'in house' consumption of PV generated electricity.

Yakky58 uses approx 1,000kWh pa and Mcfi5 uses approx 500kWh pa(and he has wife and two children at home all day)

IMO some of the estimates for the amount of generated electricity people will use are wildly optimistic and 500kWh to 1,000kWh pa is realistic. Say £50 to £100 pa.

Which makes paying £500 and £5 a month for a 'rent a roof' system absurd IMO.

Doc_N

JenR8 wrote: »

Can anyone tell me if TV reception (Or mobile phones) is affected by solar panels on your roof? Our aerial is in the roof space.

I haven't noticed any deterioration in TV or mobile reception. Our aerial's also in the roofspace, but with a booster. The mobile reception's pretty flaky here, but it's no worse now than it was before.