Solar Panels UK - is it worth it?

[scdoubleu]

Loving the Scottish Power SEG. Powerwall charging to 100% every night to maximise solar export the following day. Dishwasher, immersion, and occasionally car overnight too.

Yesterday was 17.3 kWh imported during off-peak at 7.5p/kWh, and 16.9 kWh solar exported (out of 36 kWh generated) at 12p/kWh. Tiny bit of peak grid imported, resulting in 67p profit overall.

Looking good for today too. Need to make the most of our 7.5p Go rate before it finishes at the end of this month.

 

[GRiLLA]

Loving the Scottish Power SEG. Powerwall charging to 100% every night to maximise solar export the following day. Dishwasher, immersion, and occasionally car overnight too.

Yesterday was 17.3 kWh imported during off-peak at 7.5p/kWh, and 16.9 kWh solar exported (out of 36 kWh generated) at 12p/kWh. Tiny bit of peak grid imported, resulting in 67p profit overall.

Looking good for today too. Need to make the most of our 7.5p Go rate before it finishes at the end of this month.

Interesting, so did you buy solar and battery predominantly to make money? How long until breakeven and profit?

I must admit I like feeling we are using our own electricity as much as possible in the summer months, I know in the winter we will be doing the same as you in filling our battery overnight, but for now it's about living a Good Life of self sufficiency.

 

[Pink Duck]

I’m in a world of opposite use patterns courtesy of Octopus Flux. So PW, Tesla and DHW all consume power up to 17 kW between 02:00 and 05:00, then excess solar sold for 19.62 p/kWh and overnight 18.43 p/kWh energy sold at 32.01 p/kWh between 16:00 and 19:00, leaving enough to run house until it begins again.

It feels slightly counter-intuitive, but it’s actually more cost effective to run household power draws at standard day rate of 30.72 p/kWh, given loss of solar excess sale rate or the greater loss if using overnight discount rate to replace day use, instead of sale during peak.

£200 exported in 3 weeks resulting in £101.13 credit. Helps that I have free supercharging.

 

[scdoubleu]

Interesting, so did you buy solar and battery predominantly to make money? How long until breakeven and profit?

No, that was never the original intention. But I'd be daft not to take advantage of the arbitrage opportunity presented by the 12p SEG and 7.5p Go. Note that my PW is not permitted to export, so I'm not selling my imported off-peak power.

SWMBO's "Solar Challenge" spreadsheet currently suggests breakeven 7 years after installation, so 5.5 years remaining.

 

[yessuz]

Loving the Scottish Power SEG. Powerwall charging to 100% every night to maximise solar export the following day. Dishwasher, immersion, and occasionally car overnight too.

Yesterday was 17.3 kWh imported during off-peak at 7.5p/kWh, and 16.9 kWh solar exported (out of 36 kWh generated) at 12p/kWh. Tiny bit of peak grid imported, resulting in 67p profit overall.

Looking good for today too. Need to make the most of our 7.5p Go rate before it finishes at the end of this month.

Which one tarrif are you getting for off peak?

Current IO rate is 7.5 as well

 

[scdoubleu]

Which one tarrif are you getting for off peak?

Current IO rate is 7.5 as well

Our 1-year fixed Go tariff at 7.5p/kWh off-peak finishes at the end of this month. IO doesn't play nice with home battery storage, and Octopus Flux is no use because our PW isn't permitted to export. So we're having to settle for the variable Go tariff at 9.5p/kWh off-peak.

 

[yessuz]

Our 1-year fixed Go tariff at 7.5p/kWh off-peak finishes at the end of this month. IO doesn't play nice with home battery storage, and Octopus Flux is no use because our PW isn't permitted to export. So we're having to settle for the variable Go tariff at 9.5p/kWh off-peak.

Ir cheat with IO and turn off the "intelligence" and use it as "dumb" GO

 

[phil4]

In the above how do you stop your powerwall charging from solar during the day?

 

[Pink Duck]

Switch from Self-Powered Mode to Time-of-Use, then provide tariff with cheaper overnight rate and enable Grid Import to only charge then.

 

[scdoubleu]

Switch from Self-Powered Mode to Time-of-Use, then provide tariff with cheaper overnight rate and enable Grid Import to only charge then.

This. Off-peak tariff less than export tariff (SEG).

Powerwall will (mostly) DTRT by charging to 100% overnight. During the day it uses some solar to maintain enough SoC to see us through the evening.

 

[ringi]

IO doesn't play nice with home battery storage,

Just need to connect the battery sensor and EV charger so the battery sensor does not see the power being used to charge the EV.

 

[SK6 steve]

Our 1-year fixed Go tariff at 7.5p/kWh off-peak finishes at the end of this month. IO doesn't play nice with home battery storage, and Octopus Flux is no use because our PW isn't permitted to export. So we're having to settle for the variable Go tariff at 9.5p/kWh off-peak.

Hi

if you email the Powerwall team, they will alter your Powerwall settings to allow export.

 

[phil4]

Hi

if you email the Powerwall team, they will alter your Powerwall settings to allow export.

You have to get permission first from the electricity network operator (DNO) first, and by and large it seems they don't like people exporting from Powerwalls.

 

[Pink Duck]

UKPN were fine with it for me, total of 8 kW solar and 5 kW PW2 export permitted. Some DNOs clearly don't favour export, but might be due to local circumstance. Where I live many houses now have EV charging, the concern was more from the existing amount of solar nearby (18, 20, 24 panel ones).

 

[scdoubleu]

if you email the Powerwall team, they will alter your Powerwall settings to allow export.

Nope. DNO says no. I'm at the limit for solar (6 kW) and my Powerwall is hobbled to 3.68 kW, with no export permitted. Local infrastructure doesn't have enough snot to handle any more.

 

[hooky]

I’m in a world of opposite use patterns courtesy of Octopus Flux. So PW, Tesla and DHW all consume power up to 17 kW between 02:00 and 05:00, then excess solar sold for 19.62 p/kWh and overnight 18.43 p/kWh energy sold at 32.01 p/kWh between 16:00 and 19:00, leaving enough to run house until it begins again.

It feels slightly counter-intuitive, but it’s actually more cost effective to run household power draws at standard day rate of 30.72 p/kWh, given loss of solar excess sale rate or the greater loss if using overnight discount rate to replace day use, instead of sale during peak.

£200 exported in 3 weeks resulting in £101.13 credit. Helps that I have free supercharging.

That's a nice use set up - just got 2 PWs for my solar (1 year waiting list) last week. We're on IO and I'm charging up the PWs, DHW & 2 MSs @7.5p kWh during the 6 hours, and then exporting the solar during the day @12p. We also have free SC on one of the S's but not the other and I mostly can't be bothered to drive the 5 mins to the SC and wait about with it (sometimes we take both cars down, and leaving my S charging whilst we do a food shop, but otherwise the £/hour using free electricity doesn't seem worthwhile).

You must have quite low mileage/EV charging to make those numbers work?

 

[Pink Duck]

It’s something like 8,000 mi/year for the cut-off in effectiveness of having an EV and being on Flux. Will probably be back on IO come November.

 

[hooky]

Nope. DNO says no. I'm at the limit for solar (6 kW) and my Powerwall is hobbled to 3.68 kW, with no export permitted. Local infrastructure doesn't have enough snot to handle any more.

Is the 3.68kw the charge from grid limit?

After our recent install we seem to be able to charge at full whack (10kw over 2 PWs). I'm asking the installer to ask the DNO whether we can export to grid, but hope that doesn't somehow raise our heads above the parapet such that they ask the import rate to be limited. Currently they're allowing us to export to grid from our 8kw Solar inverter.

 

[hooky]

Ir cheat with IO and turn off the "intelligence" and use it as "dumb" GO

I didn't know this was an option. I've been making the PW work via changing the "charge by" and % charge manually each evening for the past week - have now turned off the "smart charging" option.

Sort of surprised that they allow this as surely this is the only reason they'd offer a lower ovenight rate, is that they gain this control. How long have you been running dumb for? Any issues from Octopus?

 

[PITA]

Is the 3.68kw the charge from grid limit?

After our recent install we seem to be able to charge at full whack (10kw over 2 PWs). I'm asking the installer to ask the DNO whether we can export to grid, but hope that doesn't somehow raise our heads above the parapet such that they ask the import rate to be limited. Currently they're allowing us to export to grid from our 8kw Solar inverter.

Similar to us... we charge the Powerwalls at 10kW and can export up to 5kW...