How Important is Summer Solar Panel Electricity Generation?

When we first got our solar panels we hadn't realised how output varied over the year and the difference between the maximum output in summer and winter. The last few months have shown us how important summer months are for our solar panel output and how relatively insignificant the winter months are for the overall annual performance of your solar PV panels.

How Important is Summer Solar Panel Electricity Generation?

While December might have an average generation total of 100kWh, a good summer month can exceed this amount within 5 days. An exceptionally sunny summer month can generate such a massive excess over the average that winter generation is then irrelevant. The difference between 100kWh for an average December or a poor December with only 50kWh is so insignificant when a summer month can produce over 20kWh in a single day.

When we first installed the solar panels in November every day of sun was great to see the meter tick up but it is now obvious that those low amounts in winter are not important for the overall annual performance of your solar panels.

Solar Panels Generation Longest Day -Maximum Output?

As today is the longest day I am hoping that our Solar Panels will generate the maximum electricity from them as it is also a rare sunny day in June unlike the rest of the month!

Our previous high was just over 20kWh in May 2012 so I am hoping that today we will break the 21kWh barrier which is around the maximum highest output we could expect from our 3kWp solar PV panels.

Solar power generation on longest summer day

Solar Panel Feed in Tariff (FIT) Payment Delays

There are many posts on forums about the delays in payments for solar panels for the UK Feed In Tariffs and I know from speaking to a friend that they have yet to receive a payment for their panels installed 10 months ago.

The situation with British Gas (Centrica) has been very different in our experience. We have now received two FIT cheques from them for our solar panels installed 8 months ago (Nov 2011). The most recent payment has addressed some of the criticism that I'd felt with the first payment - namely that they cheque came without any supporting documentation or explanation of the calculations used.

The new British Gas Feed in Tariff advice note is very comprehensive and details the payments made under the Generation Tariff and Export tariff with a split covering the 31 March when the tariff rate changes.

British Gas FIT payments - payment summary

Well done British Gas, an excellent service and very well designed remittance advice that is supplied.

To change or submit your FIT Feed in Tariff readings to British Gas look here

Another Month Beating Estimated Solar Generation

Amazingly we have now had another month that has beaten both the SAP2009 and PV-GIS solar generation estimates for our PV Solar Panels. May was predicted at 334kWh for SAP and 347 kWh for PV-GIS but the actual output generated by the panels was 365kWh (based on generation meter not inverter)

This now makes 5 out of the 6 months that have beaten or matched the PV-GIS targets and all six months since we installed the panels have significantly surpassed the SAP predictions.

The following page shows the output by month with the highest day solar panel output, the earliest start times and end times each month as well as the maximum peak output that the 3kWp panels produced.



Solar panel electricity generation during May 2012

You can see that for May 2012 the panels started generating electricity at 05:25 in the morning and stopped generating at 20:45 at night. The actual output at these times is insignificant at 12W but it shows how the generation day extends over the summer as the panels only start generating at 08:05 in January and finish at 16:30