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

MWT

Solarchaser said:

So I think what you have shown is there are cheaper tarrifs, but you don't want to use them.
Fair enough.

They aren't necessarily cheaper though if you export as much as 75% of your production...
As ever the calculations for each of us are going to vary in terms of our import and export mix, no one solution fits all...

Solarchaser

MWT said:

Solarchaser said:

So I think what you have shown is there are cheaper tarrifs, but you don't want to use them.
Fair enough.

They aren't necessarily cheaper though if you export as much as 75% of your production...
As ever the calculations for each of us are going to vary in terms of our import and export mix, no one solution fits all...

Indeed, each person will need their own solution which works best for them.

There are plenty of cheaper IMPORT tariffs, the op doesn't want to take them because he/she would lose the export tarrif.

Hence, there are cheaper tariffs but he/she doesn't want to use them, and thats fair enough 🤷‍♂️

Screwdriva

Lifetime daily high of 26.58 kWh achieved this month, amidst what is shaping up to be an unremarkable solar year.

Solarchaser

Hmm, so they just don't seem to be as good in direct sunlight.
My 4kw 2014 system hit 28kwh on 31st May, and bearing in mind I'm about 400 miles north of you, I'd expect more from your system.

That said, the really bright days are when you don't really need as much electricity, (batteries were full and exporting by 10am) and if they are performing better in low light conditions,  that's probably what you need really.

Edit, comparatively I had a measly 8kwh on the 9th of june

EricMears

Solarchaser said:

 bearing in mind I'm about 400 miles north of you, I'd expect more from your system.

OTOH,  that 400 miles N probably means you get an hour or two longer to generate.  Apparently I need to add a few random characters before system will accept my comment as valid !

Solarchaser

EricMears said:

Solarchaser said:

 bearing in mind I'm about 400 miles north of you, I'd expect more from your system.

OTOH,  that 400 miles N probably means you get an hour or two longer to generate.  Apparently I need to add a few random characters before system will accept my comment as valid !

I thought it worked the other way.
Certainly it would seem screwdrivas starts at 5 and finishes at  let's say 8


Mine appears to start at 5:30 and finish at 7, so an hour and a half less really

EricMears

Solarchaser said:

EricMears said:

Solarchaser said:

 bearing in mind I'm about 400 miles north of you, I'd expect more from your system.

OTOH,  that 400 miles N probably means you get an hour or two longer to generate.  Apparently I need to add a few random characters before system will accept my comment as valid !

I thought it worked the other way.

Absolutely not !

It's a seasonal thing.  In the winter,  it does indeed get light later in Scotland compared to S England and gets dark earlier - hence giving a shorter day

However,  in the Summer,  dawn is earlier in Scotland and dusk later to give longer days.   Only on or around the equinoxes are day lengths the same at both ends of the country (or indeed the whole world)

And of course we're now within a couple of weeks of the Summer Solstice.

QrizB

EricMears said:

Solarchaser said:

EricMears said:

Solarchaser said:

 bearing in mind I'm about 400 miles north of you, I'd expect more from your system.

OTOH,  that 400 miles N probably means you get an hour or two longer to generate.  Apparently I need to add a few random characters before system will accept my comment as valid !

I thought it worked the other way.

It's a seasonal thing.  In the winter,  it does indeed get light later in Scotland compared to S England and gets dark earlier - hence giving a shorter day

If you check your weather forecast on https://www.metoffice.gov.uk they helpfully include the times of sunrise and sunset.

Today, Inverness gets about 1h20 more daylight than does London.

Edit to add: of course there's more to it than sunrise/set times. The sun is officially rising here before 0500 at the moment, but it doesn't strike my property until ~0600 due to high ground to my east, and there's no direct light on my array before ~0900 when the sun gets over my ridgeline. My array is then in the sun until about 2030, and sunset is after 2100.

Screwdriva

I’ve learnt, rather embarrassingly, that comparing systems/ components is a futile exercise unless located within walking distance.

That said, the bifacial panel performance remains impressive to me simply because 40% of the array is on the East/ West facing roof.

Screwdriva

Wow! Some substantial changes in the industry. A lot of the cheaper tariff suppliers are gone, Bulb/ Octopus are on the brink and if I apply current tariff rates to 2020's generation, I would have earned/ saved 20% more (and rising!)

Looks like the overinflated estimate figures were prophetically accurate in retrospect

All that said, I've decided to switch to Octopus outgoing agile, to see if I can maximize my export revenue. This will be tricky as I will need a new smart meter installed and Octopus won't share a timeline. This is why I plan on switching in late October to minimize loss of export earnings. Will post again with year end generation figures, as promised.