7.3 kW Bi Facial Rooftop Panels: ~7 year ROI: Fact OR fiction?

Screwdriva

2.5 years since installation, a few updates:

1) 2022 has seen the best performance in the month of June (& Jan/ Feb) since commissioning.

2) Octopus Exports are substantially higher than imports (Agile Import/Export tariffs) despite using the immersion heater whenever clear skies permit. Currently < 25% consumption, >75% export. Not that I'm complaining with current export prices

3) Three of my immediate neighbours have installed rooftop solar this past month (all Hyundai Panels with SolarEdge components). Expect a comparison soon!

Screwdriva

What a great feeling it is to achieve this! Solar PV paying for electricity and gas consumption, despite 1/3rd fewer export days. 

Alnat1

That's great, I'm hoping my next bill looks something similar 

Screwdriva

Another new record for generation, this time for the month of July. 580 kW = 11% of an increase over 2020's high.

I realize climate change activists are keen to attribute manmade emissions as chief contributor but I wonder how much of the heatwave can be attributed to a measurable, substantial increase in solar radiation this year?

ABrass

Screwdriva said:

Another new record for generation, this time for the month of July. 580 kW = 11% of an increase over 2020's high.

I realize climate change activists are keen to attribute manmade emissions as chief contributor but I wonder how much of the heatwave can be attributed to a measurable, substantial increase in solar radiation this year?

It depends what you mean by solar radiation. Irradiance as experienced by you or I is itself climate and weather dependent. If you have a look over Europe then it's down in Spain and up in the UK and similar latitudes. The increased irradiation is a result of climate change, not the cause.

https://www.pv-magazine.com/2022/06/27/spain-hit-by-biggest-solar-radiation-decline-in-28-years-in-march/

Solar activity (how much energy the sun pumps out) doesn't really make much difference to global temperature. It's even slightly counterintuitive as higher solar activity means more sunspots and lower irradiation, iirc.
https://climate.nasa.gov/faq/14/is-the-sun-causing-global-warming/

Short version: No, it's man made global warming.

QrizB

Met Office reported that it's been an unusually sunny July in much of the country, which goes some way towards explaining it.

Brimble

Screwdriva said:

What a great feeling it is to achieve this! Solar PV paying for electricity and gas consumption, despite 1/3rd fewer export days. 

Apologies for what I expect is going to be a stupid question, but how can you use minus amounts of gas? It it simply that they have previously used an estimate, but you've cut down your usage so they are now refunding you some of what they inadvertently overcharged?

By the way, I've read through all 24 pages of these as my introduction to solar, and thoroughly enjoyed every bit of it, but when i go through again, I may well have some other questions, I hope that's ok. Personally, having done a bit of research, the main figure I can't get to grips with is my likely usage of what I could generate, and I can see that seems to be the difficult one for many people...

Screwdriva

Brimble said:

Apologies for what I expect is going to be a stupid question, but how can you use minus amounts of gas? It it simply that they have previously used an estimate, but you've cut down your usage so they are now refunding you some of what they inadvertently overcharged?

By the way, I've read through all 24 pages of these as my introduction to solar, and thoroughly enjoyed every bit of it, but when i go through again, I may well have some other questions, I hope that's ok.  

I'm glad someone's reading all this!

The above statement shows that they have charged me for gas and electricity use and then credited me for the electricity sold to the grid. Last month, these cancelled each other out, much to our delight. 

Alnat1

March solar/battery install. I moved my energy accounts over to Octopus in April and haven't yet had to pay them anything (variable DD)

My Octopus monthly summary looks very much like Screwdriva's and as at the 31st July it is £159.31 in credit. OK, £50 of that is from the referral, hehe.

I know I've only seen the good months and winter will be very different but it does make me happy. 

Edit: I paid £1 to trigger the referral for my mate

70sbudgie

Brimble said:

Screwdriva said:

What a great feeling it is to achieve this! Solar PV paying for electricity and gas consumption, despite 1/3rd fewer export days. 

Apologies for what I expect is going to be a stupid question, but how can you use minus amounts of gas? It it simply that they have previously used an estimate, but you've cut down your usage so they are now refunding you some of what they inadvertently overcharged?

By the way, I've read through all 24 pages of these as my introduction to solar, and thoroughly enjoyed every bit of it, but when i go through again, I may well have some other questions, I hope that's ok. Personally, having done a bit of research, the main figure I can't get to grips with is my likely usage of what I could generate, and I can see that seems to be the difficult one for many people...

Self consumption is very dependent on the individual household. If you have a smart meter and can download your electricity consumption, you will be able to work out a better idea of what your self consumption might be. 

I am still getting to grips with the PVGIS, but believe you can get historical solar data. So overlaying that with your historical consumption data could give you a more personalised self consumption figure.