Solar panel performance beats SAP 2009 estimates

For the fourth month running our solar panels have comfortably exceeded the estimates given under the SAP2009 guidelines. With 7 days still to go before the end of March the estimate for the month has already been reached and the weather forecast of sun for the next 5 days is looking promising for a good output by the end of the month.

PV GIS vs SAP solar PV generation compared

When choosing the solar panels, the output estimates supplied by PV Solar UK were substantially higher than other companies and didn't conform to the SAP regulations. However so far these estimates using PV-GIS are proving a more accurate guide to the output of our system. Over the summer months the difference is less marked but over winter & spring the numbers are at least 10% higher than the SAP figures.

For example in January SAP2009 gave an estimate of 93kWh, PV-GIS 112kWh and the actual was 112. Dec was 68 for SAP2009, 101 for PV-GIS and an actual of 103kWh generated.

On current trends it appears March actual output will beat both the SAP figure of 210 as well as the PV-GIS figure of 241kWh electricity generation.