Here’s how much my 3kw system generated per year in £ since 2012
Iv cleaned maybe once a year for the past couple of years , each year the amount of £ per kw increases with inflation (not sure exact % increase).
Cost £7k and I’m on the original high tariff.
2012 - £1116.55
2013- £1212.20
2014- £1246.98
2015- £1301.86
2016- £1281.55
2017 - £1298.24
2018- £1455
2019- £1463.95
2020- £1541.50
2021- £1493.82
2022- £1675.06
2023- £1689.46 (so far , last reading due in dec)
I think cleaning has kept them in good condition and stopped the build up of dust/bird crap etc
Some pretty decent savings on your initial investment.
I have 5kw of off/on grid solar I mounted on my garage roof and shed and they are paying back nicely, definitely worth going solar.
How did you manage to get a 5kw system installed? I was told 4kw was the legal maximum on a residential address
There is no legal maximum. Going over certain other limits can require planning permission. I have a customer currently having 20Kw of panels installed on a domestic property. There are however different permissions needed for a feed in of 3.68Kw or less then the DNO (District Network Operator - local National Grid) can't refuse your connection - a G99 form. If you want to be able to feed in more than 3.68Kw then you need approval from the DNO via G98 - they can refuse your request.
We have 5Kw of solar panels on our roof 8 panels westish 4 panels southish. Our inverter is set to export (feed in) a maximum of 3.68Kw so just a G99 form and guaranteed acceptance. We rarely get more than 4Kw generated at any one time and the base house load is about 0.5Kw so our inverter never has to clip (waste) the output.
Some solar install companies try and persuade customers that the 3.68Kw limit is all that's allowed as it's a bit of work for them to apply for G98 approval and they could be refused. If they convince the customer that 3.68kw is good for them then they have an easy time.
Also if you can't have 4Kw of panels facing south then having a bit more Kw of panels facing different ways (West/East) helps during the day when the sun moves to maximise generation.
I think in years gone by, maybe when gov launched the fit tariffs to promote 25 years of guaranteed payments, they capped it at 3.68Kw and that gave rise to some people believing there was a legal limit.