Is Solar PV still worth it?

Therooster100

I am seriously considering Solar PV but I am not sure if it is still worth it?
Having received a quote for 12 panels (5KW output) with a sofar 6.0 inverter & 10KWH battery at £9,000. I use roughly 10,000 KWH of electricity a year (fully electric house)
It would make a big dint into that but £9,000 is 8 years worth of electricity! 

Petriix

Rough estimate: your 5kWp system will generate 5000kWh pa, but will only meet your full demand on 10% of all days. You will at most use around 4000kWh (80%) of what you generate and export 1000kWh. You will still need to import 6000kWh. Savings total around £550, so > 16 years ROI. If you can shift a significant portion of your usage to overnight then maybe a time of use tariff could slightly lessen that.

In all liklihood, your usage will be high in winter (when your generation is low) and low in summer so you will probably only use 50% of your total generation. That puts annual savings down to £450 and the ROI up to 20 years. 

mickyduck55

I am using about 15kW a day but even at this time of year on Octopus "GO" my daily cost is usually under £1 including standing charge.  I do all the usual stuff in the "GO" tariff period, dishwasher, washing, if only I could persuade my partner to get up to put the washing in the dryer at 3 am !

ROI was not really a consideration as almost everyone agrees the addition of Batteries is not a sound financial investment, but with interest rates as they are not much risk free investment is either. I do actually "like" having a system there is in my case some satisfaction watching the batteries filling up when the sun is shining.  Almost a full year since install of batteries but impossible / difficult to calculate savings... Solar produced 4061 kW, battery delivered 2075 kW.... I still exported 874 kW this will be lower this year as I have AC installed so when the panels are pouring power into the grid I will be cooling our bedroom

legoman62

mickyduck55 said:

I am using about 15kW a day but even at this time of year on Octopus "GO" my daily cost is usually under £1 including standing charge.  I do all the usual stuff in the "GO" tariff period, dishwasher, washing, if only I could persuade my partner to get up to put the washing in the dryer at 3 am !

Thought about using a timer

mickyduck55

legoman62 said:

mickyduck55 said:

I am using about 15kW a day but even at this time of year on Octopus "GO" my daily cost is usually under £1 including standing charge.  I do all the usual stuff in the "GO" tariff period, dishwasher, washing, if only I could persuade my partner to get up to put the washing in the dryer at 3 am !

Thought about using a timer

The issue is getting her to move it from the washing machine to the dryer

Maybe I could use an alarm clock!

Mickey666

When I moved to my current house, I was full of enthusiasm for 'going green' (solar PV & thermal, GSHP etc) but the more I investigated the options the less financially viable they seemed to be.  A 15-20 year payback time seemed just too speculative, especially with PV panels being rated for around 25 years. 

So I invested in having mains gas connected to the house instead, which cost about £500 in total.  Having mains gas then immediately kicked out any form of heat pump being financially viable as it would need to be around 400% efficient just to have the same running cost as a condensing gas boiler.  

I expect to revisit things in about 5-6 years time when my car might need replacement and I'll throw and EV into the mix, which might change the financial viability of solar PV, plus mains gas prices might also have increased relative to electricity.  So, I'm certainly not against PV but I just can't see it as a sensible financial option at the present time.

I'm still thinking about solar thermal though and deliberately specified a spare coil in my thermal store to make it an easy addition if necessary.  But mains gas is a tough competitor when it comes to cheap energy.

Therooster100

Petriix said:

Rough estimate: your 5kWp system will generate 5000kWh pa, but will only meet your full demand on 10% of all days. You will at most use around 4000kWh (80%) of what you generate and export 1000kWh. You will still need to import 6000kWh. Savings total around £550, so > 16 years ROI. If you can shift a significant portion of your usage to overnight then maybe a time of use tariff could slightly lessen that.

In all liklihood, your usage will be high in winter (when your generation is low) and low in summer so you will probably only use 50% of your total generation. That puts annual savings down to £450 and the ROI up to 20 years. 

Thanks, we are both currently WFH at the moment and will be for the foresable future as our offices have mothballed floors due to not needing as much space so we would use the electricity during the day 

Therooster100

Mickey666 said:

When I moved to my current house, I was full of enthusiasm for 'going green' (solar PV & thermal, GSHP etc) but the more I investigated the options the less financially viable they seemed to be.  A 15-20 year payback time seemed just too speculative, especially with PV panels being rated for around 25 years. 

So I invested in having mains gas connected to the house instead, which cost about £500 in total.  Having mains gas then immediately kicked out any form of heat pump being financially viable as it would need to be around 400% efficient just to have the same running cost as a condensing gas boiler.  

I expect to revisit things in about 5-6 years time when my car might need replacement and I'll throw and EV into the mix, which might change the financial viability of solar PV, plus mains gas prices might also have increased relative to electricity.  So, I'm certainly not against PV but I just can't see it as a sensible financial option at the present time.

I'm still thinking about solar thermal though and deliberately specified a spare coil in my thermal store to make it an easy addition if necessary.  But mains gas is a tough competitor when it comes to cheap energy.

I did ask how much ir was to get connected to the mains gas and it was just over 1 million! So unfortunately that's not a starter! 

Solarchaser

I'd suggest you would get a better return with more panels, as this will serve you better in the winter months when you will use more electricity for heating.
10Mwh is alot,  and so I'd say you have a good chance of using all of your electric.
Assuming you have a hot water tank, then a solar diverter would be advantageous to use the excess solar once the batteries are filled.

And moving to octopus go would also help use your battery and heat the hot water for 5ppkwh instead of 15ppkwh in the winter

Therooster100

Solarchaser said:

I'd suggest you would get a better return with more panels, as this will serve you better in the winter months when you will use more electricity for heating.
10Mwh is alot,  and so I'd say you have a good chance of using all of your electric.
Assuming you have a hot water tank, then a solar diverter would be advantageous to use the excess solar once the batteries are filled.

And moving to octopus go would also help use your battery and heat the hot water for 5ppkwh instead of 15ppkwh in the winter

Thanks. I cant get more pannnels on my roof unfortunately the maximum is 12 as we have dormer style windows which take up space! 

Solarchaser

Therooster100 said:

Solarchaser said:

I'd suggest you would get a better return with more panels, as this will serve you better in the winter months when you will use more electricity for heating.
10Mwh is alot,  and so I'd say you have a good chance of using all of your electric.
Assuming you have a hot water tank, then a solar diverter would be advantageous to use the excess solar once the batteries are filled.

And moving to octopus go would also help use your battery and heat the hot water for 5ppkwh instead of 15ppkwh in the winter

Thanks. I cant get more pannnels on my roof unfortunately the maximum is 12 as we have dormer style windows which take up space! 

Ahh yeah thats a good reason, what about a west facing roof?
It won't give you as good a return as south facing, but is very good for later summer sun and some winter sun when it's low in the sky