"Looking for a PV and EV solution"

I've an ageing deisel powered Ford Focus(ten years 75k miles) which has been brilliant but am thinking to replace it. Looking ahead Electric(second hand) seems a possible choice especially as we have two vehicles, so can use the other for long distances. We are retired with a mix of local journeys for school run etc and longer distances for holidays etc. I'm also keen on the idea of being self sufficient in generating electricity and considering combining the two. Our bungalow has roof of some 50 sq metres with a 22 degree pitch and being 20 degrees east of south facing. I'm thinking of filling the entire roof with panels in order to generate the max I can. On a good day in summer it could return circa 35kwh so I don't see a problem in supplying household needs(7kwh/day) and keeping the EV topped up. Am seeking quotations for systems of 4k only and the max that can be acheived also. Presumably I'd still get the FIT and export returns on the larger system so it would appear to me to be a sound financial investment. Battery storage is also an option but at current prices of £1000/kwh I'm not convinced of a sensible return. I note there is also a subsidy for installing a charging point. Would this be sensible? What does the team think? All replies gratefully accepted and considered.:)
East coast, lat 51.97. 8.26kw SSE, 23° pitch + 0.59kw WSW vertical. Nissan Leaf plus Zappi charger and 2 x ASHP's. Givenergy 8.2 & 9.5 kWh batts, 2 x 3 kW ac inverters. Indra V2H . CoCharger Host, Interest in Ripple Energy & Abundance.
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  • Ectophile
    Ectophile Posts: 7,276
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    Anything above 4kW of solar needs permission from the electricity supplier, so as not to overload the local grid. So that's why most systems are limited to 4kW. Also check the effect on feed-in-tariff, though that's less important these days.

    You could consider getting a battery as well as panels. My old inverter died recently, and my new system came with a small lithium battery. But at current prices, it will have to last a long time to reclaim the extra expense I paid.

    I keep looking at EVs. But I have realised that the longer I wait, the better they get. The range gets longer, there's more choice of cars, but the prices don't go up. So I'm hanging on to my old cars a bit longer while I see what happens.
    If it sticks, force it.
    If it breaks, well it wasn't working right anyway.
  • Thanks Ectophile. Certainly food for for thought there. Can I ask who my elctricity supplier might be. Is it my energy provider, UK Power networks or even some one else?
    East coast, lat 51.97. 8.26kw SSE, 23° pitch + 0.59kw WSW vertical. Nissan Leaf plus Zappi charger and 2 x ASHP's. Givenergy 8.2 & 9.5 kWh batts, 2 x 3 kW ac inverters. Indra V2H . CoCharger Host, Interest in Ripple Energy & Abundance.
  • Ectophile
    Ectophile Posts: 7,276
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    The people that would do the approving are your regional Distribution Network Operator (DNO). For anyone old enough to remember them, that would be the local "electricity board". But with loads of mergers and name changes, the name could be completely different now anyway.

    If you're going through an established installer, they should understand all the paperwork needed and would check approval before they start installing.

    You may find these days that there is no difference in the FiT payments per kWh generated, even if you go over 4kW. The rules were different when I had my system installed.
    If it sticks, force it.
    If it breaks, well it wasn't working right anyway.
  • EricMears
    EricMears Posts: 3,230
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    Can I ask who my elctricity supplier might be. Is it my energy provider, UK Power networks or even some one else?
    It will be your DNO (District Network Operator). If you're not sure who that is, your local phone book will tell you who to contact in event of a power failure or it's probably included on your electricity bills.

    I have an EV and solar panels and very pleased with both although don't find that solar power is very much help in charging the EV. I like to start the day with a full car battery so when the sun starts shining I'm either out in the car or else it's still fully charged from the night before. Charging overnight with economy7 gives me a fuel cost of below 2p per mile (compared with 15+ for local use of my diesel car) and I'm really not that bothered about trying to reduce that even more but do occasionally have a couple of hours charging at 5A if it's a fine day and we're not wanting to use any major appliances.
    NE Derbyshire.4kWp S Facing 17.5deg slope (dormer roof).24kWh of Pylontech batteries with Lux controller BEV : Hyundai Ioniq5
  • Thanks both, it's Eastern Power Networks and I've just sent off an email seeking their permission. Hope I haven't jumped the gun!
    East coast, lat 51.97. 8.26kw SSE, 23° pitch + 0.59kw WSW vertical. Nissan Leaf plus Zappi charger and 2 x ASHP's. Givenergy 8.2 & 9.5 kWh batts, 2 x 3 kW ac inverters. Indra V2H . CoCharger Host, Interest in Ripple Energy & Abundance.
  • Martyn1981
    Martyn1981 Posts: 14,713
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    Thanks both, it's Eastern Power Networks and I've just sent off an email seeking their permission. Hope I haven't jumped the gun!

    Hiya. I rang my DNO and got lots of help, but that was years ago. For actual permission the installer has to apply, but hopefully the DNO can let you know (as mine did) if it's a no - but they won't say yes without the application, just a 'minded' response.

    For upto 5kWp of panels you'll be OK with a 3.68kW capped inverter. Ideally you want permission for more from the DNO, but once hot, the panel performance will drop to about 80%, so losses won't be so bad, and all the time that generation is poor (early, late, winter, bad weather) it won't matter.

    For a split system with say East and West panels then 6kWp on 3.68kW might be fine, but I assume you'll install all panels on the SSE orientation (-20 from south).

    Size wise, go as big as possible/sensible. A lot of costs are fixed, whereas the PV panels and the roof railing are pretty cheap, so cost per Wp gets lower as you go bigger. for instance 4kWp might be £6k (£1.50 per Wp), but 6kWp might be £8k (£1.33 per Wp).

    For a larger system and no scaffolding I'd actually suggest a grand cheaper on both examples.


    For an EV, I've been thinking ahead, and I believe my PV system with a large domestic battery could provide all EV charge for the best 6 months of the year*. The bottom 6 months, gen is too low, and the ASHP will be consuming any spare, so over to E7.

    *This is based on an average generation of 15-20kWh per day across those months, and a consumption of 8kWh for the house, and an annual mileage of 8,000, daily average of 22 miles, and an EV kWh consumption (per day) of 7kWh.


    There's also a thread on the G&E about domestic battery storage. I'm watching developments with great interest but suspect the industry needs a few more years to establish itself, reach some sort of conformity, and bring prices down - but that said, a Tesla Powerwall II would work well, as per my plans, especially if I get an EV - so lots of planning for 2020-22 (ish).

    Here's the thread:-

    On-grid domestic battery storage
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Coastalwatch
    Coastalwatch Posts: 3,111
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    edited 15 February 2018 at 6:25PM
    Hi Martyn, thanks indeed for the informative response. It seems generating the power is the easy part while harnessing it to cover our needs 24/7 is quite another!

    With a modern gas combi boiler still under guarantee installed there seems little to gain from any other forms of heating?

    Your assumptions are correct in relation to both miles travelled(8k annually) and daily consumption(7kwh) so guess I shall need to consider E7. Not that I've previously been a fan, as without storage radiators, any night time savings were cancelled out by the increased daily tariff accompanying.

    I'm encouraged by others who've managed to utilise some of the peak time generation with timers for switching on/off various appliances but suspect that little more than 50% of our daily needs are likely to be covered in that period. It's fortunate that we are SSE facing as my wife prefers getting stuck into washing/drying/ironing etc in the early part of the day.

    With a say 6kwp output from SP then any surplus would be available for an EV. Being retired means we are better placed to charge whever there's surplus available although the likelyhood of availability and need being balanced are perhaps unlikely.

    I'm really encouraged on the one hand knowing we can produce more electricity than we consume, so that it's not our personal demand on the national grid requiring another nuclear or fossil fueled Power station to be built. Yet rather frustrated to learn that to be actually self sufficient we will need to shell out a similar cost by installing a battery. Unless of course other alternates exist!

    Your costs on installation appear very close too, as we've just had an online quote for a 4kwp system only at £5250, or £4500 if I sign up within a couple of weeks. I've still three others to arrive and currently in no rush to make a decision.
    East coast, lat 51.97. 8.26kw SSE, 23° pitch + 0.59kw WSW vertical. Nissan Leaf plus Zappi charger and 2 x ASHP's. Givenergy 8.2 & 9.5 kWh batts, 2 x 3 kW ac inverters. Indra V2H . CoCharger Host, Interest in Ripple Energy & Abundance.
  • zeupater
    zeupater Posts: 5,353
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    Hi Martyn, thanks indeed for the informative response. It seems generating the power is the easy part while harnessing it to cover our needs 24/7 is quite another!

    With a modern gas combi boiler still under guarantee installed there seems little to gain from any other forms of heating? ....
    Hi

    Have a read through this thread on the G&E board ... <link> ... it may be interesting considering the points raised above ...

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    B)
  • Martyn1981
    Martyn1981 Posts: 14,713
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    Hi Martyn, thanks indeed for the informative response. It seems generating the power is the easy part while harnessing it to cover our needs 24/7 is quite another!

    Hiya. You've hit the nail on the head. Welcome to the world of PV'ers. The simplest solution at this stage is to go big, as that reduces your needs when PV isn't generating, but no easy solution.
    With a modern gas combi boiler still under guarantee installed there seems little to gain from any other forms of heating?

    Have a read of the thread Z has posted. A small ASHP might be a nice compliment to your GCH (gas central heating). It will also provide air con on those 2 or 3 days a year when it's too hot in the UK. Mine is working well now, and I'd suspect that 6kWp SSE facing will generate about twice as much as my systems combined at this time of year.
    Your assumptions are correct in relation to both miles travelled(8k annually) and daily consumption(7kwh) so guess I shall need to consider E7. Not that I've previously been a fan, as without storage radiators, any night time savings were cancelled out by the increased daily tariff accompanying.

    The benefit now though, is that the PV will heavily reduce your daytime units, for instance our daily summer consumption is around 7.5kWh, but our import is only 2.5kWh. So you should find that the economics have changed.

    I don't have E7 as our leccy consumption is now pretty low, around 1,500kWh pa, but winter charging of an EV would change all that.

    I'm encouraged by others who've managed to utilise some of the peak time generation with timers for switching on/off various appliances but suspect that little more than 50% of our daily needs are likely to be covered in that period. It's fortunate that we are SSE facing as my wife prefers getting stuck into washing/drying/ironing etc in the early part of the day.

    Yep, a big system will help, but you will of course have a slight morning bias, and you will very quickly adapt to this. Also expect to watch the weather forecasts with more interest!
    With a say 6kwp output from SP then any surplus would be available for an EV. Being retired means we are better placed to charge whever there's surplus available although the likelyhood of availability and need being balanced are perhaps unlikely.

    Actually, with something like 6kWp I think you'll be fine for pretty much all of the better 6 months. Most days you will have at least 1kW spare for charging almost all day, and even after dishwashers, washing machines etc have finished, I'd expect you to have 2-3kW spare a lot of the time.

    You may find that some days you do very little EV charging due to weather, then the next you do 2 to 3 times an average charge as generation varies from perhaps 10/15kWh to 40kWh depending on the weather (based on 6kWp). I expect you will learn and adapt within days/weeks.
    I'm really encouraged on the one hand knowing we can produce more electricity than we consume, so that it's not our personal demand on the national grid requiring another nuclear or fossil fueled Power station to be built. Yet rather frustrated to learn that to be actually self sufficient we will need to shell out a similar cost by installing a battery. Unless of course other alternates exist!

    A battery would make a massive difference, but I still think we are 2yrs at least away from sensible prices.

    This may be a bit preachy, but we've invested in a range of products (via Abundance) such as PV, wind, hydro, AD, so as to hopefully mean we are generating (somewhere) to match or beat our consumption at all times. Not trying to save the planet exactly, but it just seemed like a good place to start, and we just roll any interest and debentures into more schemes.
    Your costs on installation appear very close too, as we've just had an online quote for a 4kwp system only at £5250, or £4500 if I sign up within a couple of weeks. I've still three others to arrive and currently in no rush to make a decision.

    I'm surprised by that. I've gotten a bit too used to folk posting crazy quotes on here ... £8k ...... £10k etc, that I thought you'd have to start at the silly end and work your way forward.

    I suppose the bungalow bit works in your favour. If I was getting greedy then maybe £6k for 6kWp, but that might be asking too much, but at least you've started at the right end.

    Hope the fun continues. ;)
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Ectophile
    Ectophile Posts: 7,276
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    My battery is quite small, with a usable capacity of 3kWh. At this time of year, it takes about 2 hours of sun to fully charge it.

    If I'm careful, that battery can last me all evening. On a good day, it still has enough charge the following morning to power up the central heating boiler and pump.

    But how much use it is depends on the weather during the day. On a miserable day, it's largely useless.

    But what I don't know is whether I will ever get back the extra cost of buying a system with a battery. There's a risk that the battery will never store enough power over its lifetime to pay for the cost of the electricity it's saved.

    You'd also need to know roughly how much electricity you need to store per day. If I was to plug in an electric car with a 30kWh flat battery, then my 3kWh battery in the loft would be flat within an hour, and the car would still have a nearly flat battery.
    If it sticks, force it.
    If it breaks, well it wasn't working right anyway.
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