DIY solar PV

[Radian]

  On 06/05/2022 at 18:03, Brickie said:

Been doing some VERY rough fag packet calcs on the payback time based on your £1500 mentioned & it came in at around a year-does that sound about right? Like I say,extremely crude (I’m a bit busy to devote the time to be more accurate) but my thinking is that,even if I’m so far out that it’s double that,it’s still a no brainer. 
Garage roof,self install,partial shading,4kw,family of four so loads of daytime usage. 
TIA

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Sounds a little bit optimistic if you have some shading. Have you tried using PVGIS to check your calcs?

[ProDave]

  On 06/05/2022 at 18:12, Radian said:

Sounds a little bit optimistic if you have some shading. Have you tried using PVGIS to check your calcs?

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Yes even in the south and on a perfect roof you won't get much over 3000kWh per year, which at the present 27p per kWh is about £800 so at least 2 years payback.

 

I don't get as much generation due to shading but am self using about 1800kWh per year so just shy of £500 per year.  That would be a 3 year payback for me now.

[Brickie]

  On 06/05/2022 at 18:12, Radian said:

Sounds a little bit optimistic if you have some shading. Have you tried using PVGIS to check your calcs?

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Had a quick go but didn’t seem to like Smartphone input. 

 

  On 06/05/2022 at 18:19, ProDave said:

Yes even in the south and on a perfect roof you won't get much over 3000kWh per year, which at the present 27p per kWh is about £800 so at least 2 years payback.

 

I don't get as much generation due to shading but am self using about 1800kWh per year so just shy of £500 per year.  That would be a 3 year payback for me now.

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👍 

Even so,still worthwhile as we’ll be in this house for many years. Washing machine currently does approx 10 loads per week (plus many 7-10 drying cycles),which can almost all be done to suit. HW via immersion,so potential there too. 
Thanks for the replies. 

[Nickfromwales]

  On 06/05/2022 at 18:19, ProDave said:

Yes even in the south and on a perfect roof you won't get much over 3000kWh per year, which at the present 27p per kWh is about £800 so at least 2 years payback.

 

I don't get as much generation due to shading but am self using about 1800kWh per year so just shy of £500 per year.  That would be a 3 year payback for me now.

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So basically,  based on the expected lifespan of the equipment, this is a goose which will continue to lay golden eggs for between 10 and 20 years.

“Less typing, more fitting people!!!”

[SteamyTea]

  On 06/05/2022 at 18:48, Brickie said:

(plus many 7-10 drying cycles)

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That should really be ignored in payback calculations.

If there is an alternative that uses lower energy i.e. clothes line, airing cupboard, then those numbers should really be ignored.

[Brickie]

  On 06/05/2022 at 20:38, SteamyTea said:

That should really be ignored in payback calculations.

If there is an alternative that uses lower energy i.e. clothes line, airing cupboard, then those numbers should really be ignored.

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Agreed but alternatives are only such if they are viable-if the washing line & airer are full up and the PE kit or the bedding is needed for the next day then it’s a necessity.
The drier isn’t used for convenience-far from it. 

Edited May 6, 2022 by Brickie

[joe90]

  On 06/05/2022 at 18:19, ProDave said:

which at the present 27p per kWh is about £800 so at least 2 years payback.

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Yes but where is electricity prices going? Down! I don’t think so, with Putins war and around 40% of our lecky generated by gas (currently) who knows how high the price will go. 🤔

[Nickfromwales]

  On 06/05/2022 at 20:38, SteamyTea said:

That should really be ignored in payback calculations.

If there is an alternative that uses lower energy i.e. clothes line, airing cupboard, then those numbers should really be ignored.

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Dependant on lifestyle, so very relevant to many, including me. My tumble drier goes towards central heating because the thing is always going. Suits me to chuck it in there and go about my day vs pegging out the laundry. Sounds frivolous to some ( that's you  ) but is practical to me.

Horses for courses, fleas accepted.

Edited May 6, 2022 by Nickfromwales

[SteamyTea]

  On 06/05/2022 at 21:59, joe90 said:

Yes but where is electricity prices going? Down!

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Gas prices have.

[joe90]

  On 07/05/2022 at 05:57, SteamyTea said:

Gas prices have.

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Only in the short term after a spike!

[SteamyTea]

  On 07/05/2022 at 06:24, joe90 said:

Only in the short term after a spike!

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Probably no big shocks till autumn, then, hopefully, we will have the LNG supply from the UA and USA sorted out.

Though it does depend on what Hungry does. 

[Nickfromwales]

Hungary 

  On 07/05/2022 at 06:49, SteamyTea said:

Though it does depend on what Hungry does. 

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I’m eating a bacon and egg toastie, on brown, with brown sauce. That’s what hungry is doing