Some Solar Panel Tips

Alfster

Hi guys,

A couple of questions based on speaking to a few companies that have been round to quote for panels:

> they can install 9 panels max which is 3.5kW on a south-west facing roof. We use 4500-5000kWh/year. Would you say this would be enough/worth it if we intend to stay at this house as a forever home?

> both companies quoted for JAM manufacturer panels. Is there much in it between manufacturers? 

> is the battery option worth considering based on the array power and annual consumption?

Any tips are much appreciated! 

QrizB

Alfster said:

> they can install 9 panels max which is 3.5kW on a south-west facing roof. We use 4500-5000kWh/year. Would you say this would be enough/worth it if we intend to stay at this house as a forever home?

If that's what fits, I'd say go for it. You're a relatively high user; do you know where it all goes, and will you be able to shift your loads into daytime?

> both companies quoted for JAM manufacturer panels. Is there much in it between manufacturers? 

I've heard of JA Solar but not JAM; is that a typo?

JA Solar are a major Chinese manufacturer. Some people will tell you to pay a premium for non-Chinese panels but I've not heard any specific complaints about JA.

You could ask your installers if they have any other options, and see how prices compare.

> is the battery option worth considering based on the array power and annual consumption?

Yes and no. Right at the moment electricity prices are crazy, which means the payback time for batteries has come down a lot. But if prices relax in a couple of years, your payback time will extend too.

The next paragraph is a bit speculative.

A 3.5kWp array might generate 3000kWh/yr. Without a battery you might use 1200kWh of that (I would say 900kWh but I've bumped it up to reflect your higher-than-average use); adding a 4-6kWh battery for £3k could allow another 800kWh of self-consumption.

800kWh will be worth about £400 when electricity is 50p/kWh from October, so you're looking at a 7-8 year payback time.

But hopefully prices will fall back to 25p/kWh before too long, and if they do that 800kWh will only be worth £200, doubling the remaining payback time.

ggmf

JAM = JA Solar https://www.jasolar.com/uploadfile/2018/0807/20180807053738266.pdf

Where are you based, have you looked at the PVGIS website to give you and estimated generation figure for the proposed size of array?

Somebody will be along in a minute having a pop at Chinese manufactured products.

Screwdriva

Alfster said:

Hi guys,

A couple of questions based on speaking to a few companies that have been round to quote for panels:

> they can install 9 panels max which is 3.5kW on a south-west facing roof. We use 4500-5000kWh/year. Would you say this would be enough/worth it if we intend to stay at this house as a forever home?

> both companies quoted for JAM manufacturer panels. Is there much in it between manufacturers? 

> is the battery option worth considering based on the array power and annual consumption?

Any tips are much appreciated! 

Whereabouts are you located? Any shading on the roof?

I recommend Hyundai or Sharp 400W Black panels. Both are excellent alternatives to the Chinese stuff and are priced v. similarly. I'd also recommend a SolarEdge or Enphase inverters. 

I'd skip the battery and take advantage of the Octopus Agile Outgoing SEG tariff. At these prices, a battery wouldn't pay for itself. If market prices crash, you can always add a battery at a later time. The good news is they're only getting better with time! 

Exiled_Tyke

Screwdriva said:

Alfster said:

Hi guys,

A couple of questions based on speaking to a few companies that have been round to quote for panels:

> they can install 9 panels max which is 3.5kW on a south-west facing roof. We use 4500-5000kWh/year. Would you say this would be enough/worth it if we intend to stay at this house as a forever home?

> both companies quoted for JAM manufacturer panels. Is there much in it between manufacturers? 

> is the battery option worth considering based on the array power and annual consumption?

Any tips are much appreciated! 

Whereabouts are you located? Any shading on the roof?

I recommend Hyundai or Sharp 400W Black panels. Both are excellent alternatives to the Chinese stuff and are priced v. similarly. I'd also recommend a SolarEdge or Enphase inverters. 

I'd skip the battery and take advantage of the Octopus Agile Outgoing SEG tariff. At these prices, a battery wouldn't pay for itself. If market prices crash, you can always add a battery at a later time. The good news is they're only getting better with time! 

SolarEdge is expensive and only worth paying for if you have shading issues or multiple panel orientations which would reduce output using a standard inverter. 

Whether or not a battery will ever pay for itself is an ever evolving debate.  I thought mine might just about be worthwhile when I  invested in it but it's looking more and more likely now. Currently it is saving me a fortune. My electricity bill is almost all standing charge.  However even in the current climate I don't find the debate helpful. Rather I would see investment in a battery as a hedge against electricity prices.  You make your investment knowing that you've locked in a decent amount of electricity which is not susceptible to price fluctuations. That for me is worth it.  Ultimately it is more about your choice and preferences rather than there being a definitive answer.  

Octopus Agile is not my preferred way forward. This locks in more uncertainty. That said good returns are to be had but without looking into it, I suspect that at some point in the future the best prices will be when PV production is too low to benefit substantially. 

2nd_time_buyer

.Octopus Agile is not my preferred way forward. This locks in more uncertainty. That said good returns are to be had but without looking into it, I suspect that at some point in the future the best prices will be when PV production is too low to benefit substantially. 

I suspect the best price will be when solar and wind is low.

The UK has gone in for offshore wind in a big way. So prices may be more influenced by wind than solar.

Exiled_Tyke

2nd_time_buyer said:

.Octopus Agile is not my preferred way forward. This locks in more uncertainty. That said good returns are to be had but without looking into it, I suspect that at some point in the future the best prices will be when PV production is too low to benefit substantially. 

I suspect the best price will be when solar and wind is low.

The UK has gone in for offshore wind in a big way. So prices may be more influenced by wind than solar.

Again, I haven't checked this, but I suspect that best Outgoing prices are early evening when demand tends to be highest. But this is when PV systems are winding down at this time of year and in other month or so won't producing at all. 

Screwdriva

Exiled_Tyke said:

SolarEdge is expensive and only worth paying for if you have shading issues or multiple panel orientations which would reduce output using a standard inverter. 

SolarEdge is an excellent product as well. I would not hesitate to pay any peace-of-mind premium for their inverter with 25 year warranty vs. cheaply manufactured options that flood the market. 

Exiled_Tyke said:

Whether or not a battery will ever pay for itself is an ever evolving debate.  I thought mine might just about be worthwhile when I  invested in it but it's looking more and more likely now. Currently it is saving me a fortune. My electricity bill is almost all standing charge.  However even in the current climate I don't find the debate helpful. Rather I would see investment in a battery as a hedge against electricity prices.  You make your investment knowing that you've locked in a decent amount of electricity which is not susceptible to price fluctuations. That for me is worth it.  Ultimately it is more about your choice and preferences rather than there being a definitive answer.  

Octopus Agile is not my preferred way forward. This locks in more uncertainty. That said good returns are to be had but without looking into it, I suspect that at some point in the future the best prices will be when PV production is too low to benefit substantially. 

There really shouldn't be a debate on this. Either the numbers highlight a battery saves you money or it doesn't. If your goal was primarily to minimize import back when SEG was pathetically low, yes, a smaller battery made some financial sense with a foreseeable payback within its warranty period.

However, when you are being paid over 50% more for energy sale (vs. the price cap), even at mid day, the battery financial argument flies out the window. The only unknown is how long energy prices will remain high? Based on geopolitical events, I would argue for quite a while . . .

Alfster

QrizB said:

Alfster said:

> they can install 9 panels max which is 3.5kW on a south-west facing roof. We use 4500-5000kWh/year. Would you say this would be enough/worth it if we intend to stay at this house as a forever home?

If that's what fits, I'd say go for it. You're a relatively high user; do you know where it all goes, and will you be able to shift your loads into daytime?

> both companies quoted for JAM manufacturer panels. Is there much in it between manufacturers? 

I've heard of JA Solar but not JAM; is that a typo?

JA Solar are a major Chinese manufacturer. Some people will tell you to pay a premium for non-Chinese panels but I've not heard any specific complaints about JA.

You could ask your installers if they have any other options, and see how prices compare.

> is the battery option worth considering based on the array power and annual consumption?

Yes and no. Right at the moment electricity prices are crazy, which means the payback time for batteries has come down a lot. But if prices relax in a couple of years, your payback time will extend too.

The next paragraph is a bit speculative.

A 3.5kWp array might generate 3000kWh/yr. Without a battery you might use 1200kWh of that (I would say 900kWh but I've bumped it up to reflect your higher-than-average use); adding a 4-6kWh battery for £3k could allow another 800kWh of self-consumption.

800kWh will be worth about £400 when electricity is 50p/kWh from October, so you're looking at a 7-8 year payback time.

But hopefully prices will fall back to 25p/kWh before too long, and if they do that 800kWh will only be worth £200, doubling the remaining payback time.

Thanks for this info. No I’m not sure where it all goes. Can’t quite figure it out. When we moved in (June last year) we had a day and night meter but we were charged the same rate for day and night. My wife and I were away during the day at work. All the lights are LED, appliances are quite efficient etc. We have nothing in our house electrically that would be different from any other house. What I really don’t get is our useage has dropped dramatically since we had a smart meter installed last month. Furthermore, my wife has been on maternity leave since June so she has been in during the day since the smart meter was installed yet we are using about half the energy??! I have attached readings from the old meter which were actual readings and not estimates as well as some new smart meter readings. I think the previous owners for some reason left the immersion programmed on at night despite the night rate being high and the same as the day. I turned this off permanently though when I found out which was about a month tops after moving in. So pretty stumped, I really do think our electricity useage doesn’t change throughout the year - only our heating and hot water which is all oil. 

So based on this new smart meter maybe it’s more like 3.5k per year. I mean the June 2021 to June 2022 useage on the old meter is 4800kWh still. It is a large 5 bedroom house but electricity wise I really don’t think we use any appliances beyond what is typical.

 

Alfster

Screwdriva said:

Alfster said:

Hi guys,

A couple of questions based on speaking to a few companies that have been round to quote for panels:

> they can install 9 panels max which is 3.5kW on a south-west facing roof. We use 4500-5000kWh/year. Would you say this would be enough/worth it if we intend to stay at this house as a forever home?

> both companies quoted for JAM manufacturer panels. Is there much in it between manufacturers? 

> is the battery option worth considering based on the array power and annual consumption?

Any tips are much appreciated! 

Whereabouts are you located? Any shading on the roof?

I recommend Hyundai or Sharp 400W Black panels. Both are excellent alternatives to the Chinese stuff and are priced v. similarly. I'd also recommend a SolarEdge or Enphase inverters. 

I'd skip the battery and take advantage of the Octopus Agile Outgoing SEG tariff. At these prices, a battery wouldn't pay for itself. If market prices crash, you can always add a battery at a later time. The good news is they're only getting better with time! 

Thanks. We are based in Hertfordshire. No shading on the main roof but only part of the roof can be used as we are in a conservation area. The 9 panels comprises of 7 on the main house roof (SW facing) and 2 on the flat roof they said. 

Exiled_Tyke

Screwdriva said:

Exiled_Tyke said:

SolarEdge is expensive and only worth paying for if you have shading issues or multiple panel orientations which would reduce output using a standard inverter. 

SolarEdge is an excellent product as well. I would not hesitate to pay any peace-of-mind premium for their inverter with 25 year warranty vs. cheaply manufactured options that flood the market. 

Exiled_Tyke said:

Whether or not a battery will ever pay for itself is an ever evolving debate.  I thought mine might just about be worthwhile when I  invested in it but it's looking more and more likely now. Currently it is saving me a fortune. My electricity bill is almost all standing charge.  However even in the current climate I don't find the debate helpful. Rather I would see investment in a battery as a hedge against electricity prices.  You make your investment knowing that you've locked in a decent amount of electricity which is not susceptible to price fluctuations. That for me is worth it.  Ultimately it is more about your choice and preferences rather than there being a definitive answer.  

Octopus Agile is not my preferred way forward. This locks in more uncertainty. That said good returns are to be had but without looking into it, I suspect that at some point in the future the best prices will be when PV production is too low to benefit substantially. 

There really shouldn't be a debate on this. Either the numbers highlight a battery saves you money or it doesn't. If your goal was primarily to minimize import back when SEG was pathetically low, yes, a smaller battery made some financial sense with a foreseeable payback within its warranty period.

However, when you are being paid over 50% more for energy sale (vs. the price cap), even at mid day, the battery financial argument flies out the window. The only unknown is how long energy prices will remain high? Based on geopolitical events, I would argue for quite a while . . .

I stand by what I said before.  Buying a Solar Edge inverter when you don't have shading issues or more than two orientations is paying for functionality that you don't need. Unless things have changed since my install, my experience is that most electricians charge more for an SE installation as there is more work involved.  I'm sure others can recommend some quality 2-string inverters. But I can't as I've no experience of them. 

I'm happy to admit that Agile is currently offering some great prices but it is uncertain and volatile. In the last three months there have been a number of occasions in my area when at my peak production time the price has been 0.2p and even 0.0p.   Meanwhile my battery is saving me a certain 40 odd pence per unit.