Renewables: "talking 'bout my generation"

jimjames

Checked our numbers last night and already with 4 months to go have beaten the SAP2009 numbers on our MCS certificate.

MCS: 2479 kWh
Actual: 2515 kWh (Nov 2011 to Aug 2012)

3kWp panels, SE England, SSW facing

With the additional 180kWh in August if the inverter had been working we would be way over.

sly_dog_jonah

don0301 wrote: »

probably worth stating whether its Climate-SAF or Classic PVGIS

I'm sure people use both, so it gets confusing

Valid point, it was Classic PVGIS. For our location though the difference is only 60kWh/year (Climate-SAF is the higher of the two).

I ran our system stats through the calculator again, and I'm getting different results than 12-odd months ago when I first ran our system through. Although Google Maps now plots our postcode slightly more accurately than last year, the difference does not account for the result. The main difference seems to be the temperature losses, which I've no explanation for the difference:

Solar radiation database used: PVGIS-classic (Result on 7th Sept 2012):
Nominal power of the PV system: 3.7 kW (crystalline silicon)
Estimated losses due to temperature: 7.6% (using local ambient temperature)
Estimated loss due to angular reflectance effects: 2.9%
Other losses (cables, inverter etc.): 14.0%
Combined PV system losses: 22.9%
Total for year: 3200kWh

Solar radiation database used: PVGIS-classic (Results late 2011)
Nominal power of the PV system: 3.7 kW (crystalline silicon)
Estimated losses due to temperature: 11.9% (using local ambient temperature)
Estimated loss due to angular reflectance effects: 3%
Other losses (cables, inverter etc.): 14%
Combined PV system losses: 26.5%
Total for year: 3060kWh

So it looks like I need to update my spreadsheet with slightly higher PVGIS targets for each month. We've still exceeded PVGIS (Classic) by 8.2% since installation.

Has anyone else noticed a difference between PVGIS classic calculations now versus last year or older?

don0301

yeah last Jan my estimate for PVGIS_SAF was 4030

now, its 3850

PVGIS have apparently added June 2010-end 2011 data to Climate-SAF PVGIS! (look in news section)

http://re.jrc.ec.europa.eu/pvgis/index.htm

the data was added in Feb

most parts of UK irradiance has increased so I dont know why my estimate is now lower

on the plus side, my spreadsheet looks better

sly_dog_jonah

jimjames wrote: »

Checked our numbers last night and already with 4 months to go have beaten the SAP2009 numbers on our MCS certificate.

Ah thanks for the tip, hadn't noticed the MCS certificate had the SAP estimate.

So our SAP estimate is 2951kWh, versus PVGIS-Classic 3200kWh & PVGIS-Climate-SAF 3260kWh.

Generation so far 3055kWh as of yesterday with 44 days to go to anniversary.

sly_dog_jonah

don0301 wrote: »

PVGIS have apparently added June 2010-end 2011 data to Climate-SAF PVGIS! (look in news section)

Hmm but PVGIS-Classic database hasn't changed so that doesn't explain my difference in results.

don0301

sly_dog_jonah wrote: »

Hmm but PVGIS-Classic database hasn't changed so that doesn't explain my difference in results.

dunno

I just noticed that Climate PVGIS had changed

its the more accurate one anyway

Martyn1981

jimjames wrote: »

Checked our numbers last night and already with 4 months to go have beaten the SAP2009 numbers on our MCS certificate.

MCS: 2479 kWh
Actual: 2515 kWh (Nov 2011 to Aug 2012)

3kWp panels, SE England, SSW facing

With the additional 180kWh in August if the inverter had been working we would be way over.

Good news.

Pointless SAP figures again! Standardising the UK doesn't work with a 20% difference or so N v's S, plus local weather conditions. Presumably you'd expect 3,000(ish)?

Mart.

jimjames

Martyn1981 wrote: »

Good news.

Pointless SAP figures again! Standardising the UK doesn't work with a 20% difference or so N v's S, plus local weather conditions. Presumably you'd expect 3,000(ish)?

Mart.

Yes I'm hoping for just over 3000kWh for the full year. Might be a bit skewed now with the loss of generation in August but according to my estimates it was looking like 3200 so if the rest of the year goes to plan so may just squeak over the 3000kWh barrier anyway.

With the FITs and electricity savings it is looking very promising.

shafeeq

Hi

10.35 kWh today. At 11.30 I had about 1kwh

Shafeeq

KevinG

Stopped generating a little early but got 11.62kWh so can't complain