A photo from the newly installed CCTV camera showing part of the roof-mounted solar PV array.
Time for an update on the performance of my PV panels. A nominal 4.92 kW of panels installed as two separate arrays and 'activated' on 9th December 2005 has been in operation for more than 16 years. The original cost was £25,000 although there was a grant of 50% at the time. I also receive just over 14p/kWh from EON for all the electricity I produce.
The last report was rather brief and I had intended to expand upon it with some explanatory data. See here, here and here for related links.
The PV solar panels are maintenance-free although two components have failed since installation. One of the two inverters failed in August 2015 after 9½ years in service; it took 6 months to replace for a number of reasons including the original installer going out of business. Cost £1087.37 including fitting and testing. In August 2020, after nearly 15 years in use, the generation meter started to fail (intermittent readings) and then completely failed (no readings) in December 2020. A replacement meter was fitted on 17th February 2021 (delay due to COVID). Cost £72 including installation and testing. Caplor Energy were supplier and fitter for both items.
The table below summarises the total annual electricity generation readings from both solar PV arrays, along with the annual sunshine hours recorded at the Ross-on-Wye weather station.
[Note 1: Annual readings on the 8th December were taken until December 2012; thereafter, monthly readings on the 8th of the month. Note 2: The data for each calendar year covers the period from December to December; e.g. 2010 reports the elelectricity generated and sunshine hours measured from December 9th 2009 to December 8th 2010. This is to match up with the number of operational years. Note 3: Sunshine hours are taken from the Met Office's Ross-on-Wye weather station. Note 4: Sunshine hours at Ross-on-Wye changed from Campbell-Stokes recorder to Kipp & Zonen sensor at the end of 2018. I have used a correction factor of 1.2 to convert KZ values to CS values. Note 5: PV generation data between August 2015 and December 2015 underestimated due to failing/failed inverter; no correction has been made to the generation measurements for 2015. Note 6: No generation data are available for December 2020 and January 2021 due to meter failure; value for February 2021 will be under-reported. Estimates for generation data for these 3 months, using data from the previous 4 years, have been used to fill in the gaps.]
Annual PV generation data are summarised in the histogram below.
As noted previously, the efficiency of the PV panels is expected to decrease with age but this has been offset by a small but noticeable rise in annual sunshine hours.
Since 2012, I have been collecting monthly generation data and this allows me to dig a little deeper to see when the extra sunshine hours occur. Approximately 90% of the electricity generated is during Spring (MAM), Summer (JJA) and Autumn (SON) so this is the obvious place to look for changes in sunshine hours using electricity generation as a proxy for sunshine hours.
Over the 2012-2021 period, PV generation increased during Spring (March, April, May: MAM), slight decrease/no change in Summer (June, July, August: JJA) and a small increase in Autumn (September, October, November: SON). In total, based on linear regression best fit, there was an increase in PV generation of approximately 40 kWh/year over this period - or about 1% per annum - due to increased solar radiation. The linear relationship between sunshine hours and PV generation is illustrated below.
By implication, the efficiency of the solar panels is also decreasing by about 1% per annum which is roughly in line with expectations.
Here's hoping for sunny weather in 2022...
Posts
0 comments:
Post a Comment