Help and guidance please on solar energy

tunnel

Your survey is a difficult one, you see, when people have solar installed their outlook to energy use changes. If they made no changes to their daily routines then you could get a straight answer....but they don't, everything changes, either upgrades to white goods, timer switches, diverters, monitors and plain old stick your head out the window to see if the suns shining. There's so many differentials that getting a straight answer is nigh on impossible


As for the other questions...see above and then tell me how long is a piece of string, you may even find someone with a 2kWp system generating 2000kWh a year may be using 2500kWh a year less due to better awareness and upgrades, how much of the difference can be put to solar.


Me personally, I dropped from 8500kWh a year to 3400kWh, I generate around 5000kWh but probably only use 50%, the drop is due to better awareness and upgrades to white goods, even down to using a travel kettle(which the wife moans about everytime its turned on...lol).


There will always be someone somewhere who will try to take advantage of the gullible, the guys and gals on these forums can't help them all but they'll have a damn good try to help prevent robbing bar stewards from taking advantage. It's the nature of the forum....moneysaving!!

ispookie666

Solar quote are very widespread.
We had a 3.5KWp installed + enphase micro inverters.
The quotes we had ranged from 4800 to 9000.
If shading is a problem - micro inverters are said to be great

Martyn1981

Love_Solar wrote: »

I have taken your comments on board about the leccy price increases per year and will adjust my calculation when seeing customers in the future.

Thanks for that. Going back to 2010, I can see how the idea/practice of compounding high leccy price rises started. However stopping and thinking now, especially with the advantage of now knowing where the prices of the main renewables are going, means that it's no longer sensible to use that prediction.

Love_Solar wrote: »

What amount of KWs and percentage of total generation will each property save from the generated solar power?

When I receive my results from my small survey from my past customers I will publish online.

I'm afraid I can't answer that. One thing to note is that PV should cover baseload, even if only 2 panels, for most of the generating period. Perhaps 10hrs a day (on average). So perhaps £40 minimum (100W x 10hrs x 365days x 11p) or £75 (150W and 14p).

A higher consumption house could be expected to consume more leccy in the evenings, weekends and holidays than a lower consumption house, and therefore save more, but again this will be based on assumptions.

I'd be very grateful if you could post your findings on here. If you've glanced at the PV FAQs you'll see I suggested a saving of £120 (£80 to £160), with higher savings possible. A year or so back I asked the folk on the PV generation thread if they thought I should bump that figure up a little. I'm concerned that too high a figure will mislead those considering PV, but with marginal returns, whilst at the same time, not wanting to downplay savings.

The consensus of opinion was to leave the figure alone. Higher savings are possible, but potential PV'ers should be sensible, until they have real results to compare perhaps a year into the install.

Love_Solar wrote: »

With regard “I’ve been a massive fool My Planet”, this is the company which I had to investigate in Spalding and court action is going to take place for miss selling.

I'm very glad to hear that. If you have read the thread and my posts on there, you'll understand why I'm very grateful for any contribution you've made. PV at a reasonable price is a great investment for most (suitable) households, but the prices those guys are charging are an insult, and chucking in some LEDs (nothing wrong with LEDs) just so they can bump up the compounded leccy savings is seriously dodgy.

It's crossed my mind several times that if I was to sit down with people considering PV, I could chuck dozens of numbers at them, off the top of my head (4kWp, 3.68kW, 250Wp, 12.92p, 4.85p, 10 to 14p leccy, 4,000kWh, 20 years, 30%, 50%, panel efficiencies, inverter efficiencies, orientation, roof pitch, payback years and so on) all with a positive and a smile, followed by a stupidly high price and a sign here.

What hope do most people have when considering something that simply drips with numbers? I love numbers, the more the better as they usually expose tricks if you keep em all in your head and check each against the others as the story develops, but most folk get swamped.

Lastly can I say that I have nothing against installers, I chat with quite a few on the Navitron forum and they've given me tons of info and advice, even answers to some problems/questions asked on here. This site often needs the input and specialist knowledge of installers. Also I got the idea of the PV'ers PV FAQs as I personally found the info on most PV installer sites to be very good and informative, but ..... how was I (or anyone else) to know that it could be trusted when considering a spend of 12 grand or so (back then).

There used to be an installer on here, extremely nice guy, but he gave up a couple of years back as he ended up having to defend the entire renewables policy against a few moaners. But we don't see that much of the moaners anymore, now that prices and subsidies have tumbled, and PV has proven to work very well so far.

Thanks again.

Mart.

Martyn1981

Love_Solar wrote: »

What savings per family do you think they will make per year?

Hello again. Prompted by your question, and earlier reference to the EST, I gave their site and calculator another glance. I've previously rung them up to complain about a number of errors and even some faults on their site (yes, I am that bad!).

It looks like they've given it another overhaul, and it seems to be pretty good now. I entered my approx info on their calculator, describing my ESE system as 3.5kWp and the generation figure of 2,763kWh is very close to my target of 2,800.

Unfortunately they still calculate leccy savings as a direct % (25%) of generation, so a 4kWp system would according to them save twice as much as a 2kWp system!

Changing my specs to 1kWp gave a leccy saving estimate of £28, which for reasons previously explained, is ridiculously low since even a tiny 1 or 2 panel system would significantly contribute to baseload at the very least.

Still, the calculator and info is pretty good now. I also note that they give a table of suggested household savings from a 4kWp system at 4 locations around the UK. The average saving is £122.50pa (£110 - £135).

Mart.

Love_Solar

Question one answer


They all have a 4 kW Solar PV system installed which generates 4000 KWh per year per house as they all face the same direction. The only difference is the family electrical consumption per year. They all pay the same price per kw and that is 11p per kw.

1st family use only 2000 kwh per year
Answer 34% of consumption 680 kwh @ 11 p = £74.80
2nd family use 4000 kwh per year
Answer 30% of consumption 1200 kwh @ 11p = £132.00
3rd family use 6000 kwh per year
Answer 28 % of consumption 1680 kwh @ 11p = £184.80
4th family use 8000 kwh per year
Answer 25 % of consumption 2000 kwh @ 11p = £220.00

What savings per family do you think they will make per year?
answer in red text


Lets take the 4 KW solar pv system and expected savings of £140.00 by using the 25% rule of the total generation of the pv system from the EST calculator.

You say 25% of the generation which equals 1000 kw of the 4000 kw generated, without taking in to consideration the customers usage per year, and using the EST average price of 14p per kw.

1000 x 14p = £140.00 reguardless of consumer annual consumption.

Now I say to use the 30% rule of customer consumption per year.
4000 @ 30% = 1200 kwh per year.
1200 kwh x 14p = £168.00 per year , not a get deal of difference you might say when using the national average usage, but what happens when the customer is using more or less than the national average.

A customer using 2000 kwh per year and your savings with a 4 kw system generating 4000 kwh per year.
4000 / 25% x 14 p the same as above £140 per year but this is 50 % of the customer annual consuption which is not possible as we all know.

My rule is the maximum percentage of 34% of 2000 kwh per year which equals 680 kwh per year or 680 x 14p = £95.20 per year saving.


Lets go to the other end, when a customer is using 8000kwh per year.


My rule 26% as listed in earlier posts (26% to 34%)
8000 x 26% = 2080 kwh per year
Now this is over the MCS rules of 50% used in the home and 50% exported to the grid of the total generation of the PV system, so I would change my calculation to 50% of the total generation 4000 / 50% = 2000 kwh
2000 x 14 p = £280.00.

You’ll notice my % changes with what the customers annual usage, the lower the annual consumption the lower percentage the higher the consumption is the higher percentage.

Now who is miss leading the customer about savings on their electric bills?


Energy Saving Trust Solar Energy Calculator.
When I enter my annual consumption of 4000 per year on the EST website calculator and have a 1.5 kW system installed and it generates 1300 kw per year it quotes my savings on my electric bill as £43.00, which is 25% of the 1300 kw total genartation at 14 pence per kw. This is far to low and the proof is below.

My consumption and solar PV generation at home.
Usage 11.2 kw per day just over 4000 kwh per year.
Solar PV system size of 1.44 KW generating 1300 kwh per year in Lincolnshire.

My Solar PV system will generate the following power over the year.
Jan 36.04
Feb 51.67
Mar 100
Apr 149.92
May 175.78
Jun 181.38
Jul 181.57
Aug 151.78
Sep 121.04
Oct 88.45
Nov 48.99
Dec 31.88
Total 1319 KWh

Over the last 102 days I have imported 826 KWh
My PV has generated 539 KWh
I have used 355.8 KW
Exported 183.2 kW (which has gone in to the immersion heater via immersun unit).

So I have used 355.8 KW out of a possible 539 KW which is 66% of the total generation so far, and exported 33%. Over the following year and back around to 15th April 2016 my system will generate the remaining 761 KWhs, but as the days get shorter, I will of course generate less per day I will export less, during the shortest days of the year in November December and January what ever I generate I will use within the home as the system will only generate between 0.5 to 2 KW per day. Therefore the percentage can only go up from 66% to expected 75% of the total generation (1300 x 75% = 975kW), not the 25% which the EST says I will save on my electric bill. The EST expect me to save 25% of 1300kw = 325 kW this I’ve all ready save over the past three months.

As the FITs prices drop it’s more important to make the best saving on your own electric consumption. The government are looking to slash the subsidy for solar PV installations, this has been in the news just recently. It’s very important the EST get the correct figurers to the customers as no one will install a solar PV system and save £43 by installing a 1.5 kW system, when in reality they would save about £110 off their bill.

Question Two
You have again four properties with the same amount of people living in them as above but this time they all use the same amount of electric per year, the National average of 3500 KWh per year, this time they all have different size solar PV systems installed.
1st property has a 2 kw solar pv system fitted generating 2000 kw per year
2nd property has a 2.5 kw solar pv system fitted generating 2500 kw per year.
3rd property has a 3 kw solar pv system fitted generating 3000 kw per year
4th property has a 4 kw solar pv system fitted generating 4000 kw per year.

What amount of KWs and percentage of total generation will each property save from the generated solar power?

Answer is
All properties will save about the same amount of electric using the 30% rule
3500 kwh Natioanl Average x 30% = 1050 kwh per year.

And percentages are
1st property 2000 generated 1050 used, 52% of total generation
2nd property 2500 generated 1050 used, 42% of total generation
3rd property 3000 generated 1050 used, 35% of total generation
4th property 4000 generated 1050 used 26% of total generation


Price of my 3.1 KW Solar PV system being to expensive

If I where to install a 3.1 kw system without solaredge system with optimisation units this would reduce the price by £420 as the inverter are about the same price, take away the extened warranty for the solaredge inverter of £156.00 and don’t use a scaffolding company but a tower scaffold or Easi Dec then another £400 could be reduced bring the price down to about £4K not 5K.
I can and do install 4 KW system for the 5K price with REC solar Panels and SMA inverters. When you informed me about buying my materials from the company you suggested online I did some investigation work on the company and they are selling products well below recommended retail prices, REC and SMA will be looking in to this as they don’t want their products discounted online showing Trade prices as retail prices we all need to make profit in every business.

Solar PV Price Guide for consumers
2 KW system from £3000.00
3 KW system from £4000.00
4 KW system from £5000.00
plus VAT 5%
For a standard string inverter

One last thing for anyone thinking about installing solar panels?

Self funded Solar Panels by taking out a loan over ten years.
Typical 4 kW System cost over £7500.00 + VAT Plus interest.


“DON’T DO IT” It won’t pay for its self, buy a 1.5 or 2 KW system for the above price or what you afford without taking out any loans.


Andrew

EricMears

There are no simple answers to those questions.

How much of your own generation you can use is subject to a lot of unasked questions.

If occupants are at home all day and able to use major appliances when sun shines (or indeed if they have an Immersun or similar) then they may well be able to use all of their own generation (or 100% of their daytime consumption if less).

Without the Immersun or people at home during day, they'd only be able to save the cost of their base load (typically : a fridge, freezer, and a few minor appliances on standby mode - perhaps only a couple of kWh per day or less than 10% of generation on decent days).

Martyn1981

Hiya Andrew. Thanks for the info.

Firstly, I'm not entirely sure if you are chatting, arguing or agreeing, so if I get any guesses wrong, please don't hold that against me.

Leccy savings - Not sure if you are referring to me with this:-

Love_Solar wrote: »

You say 25% of the generation which equals 1000 kw of the 4000 kw generated, without taking in to consideration the customers usage per year, and using the EST average price of 14p per kw.

1000 x 14p = £140.00 reguardless of consumer annual consumption.

and,

Love_Solar wrote: »

Now who is miss leading the customer about savings on their electric bills?

However, your examples of leccy savings range from £75 to £220. Now please compare those figures to the full advice in the PV FAQs:-

Martyn1981 wrote: »

Savings will vary from household to household, but could be approx. £120 (probably in the £80 to £160 range). Larger savings are possible, but will require higher daytime consumption.

I think it's fair to say that we are in general agreement. Yes, I generally abbreviate the figure to £120 when chatting on threads, but at the same time I also tend to include a reference to the FAQs for fuller advice. As previously advised, we (MSE PV'ers) reviewed this advice a while back and concluded that it was reasonable, and better to be on the safe side for those considering PV.

For us, if we get it wrong, either way, people won't mind too much, for yourself, if you overstate savings you'll be accused of miss-selling.

My main issue with your earlier posts was the high energy price inflation you were using, but you said you would change that, so possibly we are in agreement over both current and future savings, though we may have gone round the houses to get there?


EST - I think we are in total agreement that their small system leccy savings figure is far too low?


System costs(a) - Again, the figures you give as possible costs for a simple system seem to stack up with what folk on here have been posting over the last 9 months, £5k+.

System costs(b) - Oh dear:-

Love_Solar wrote: »

I can and do install 4 KW system for the 5K price with REC solar Panels and SMA inverters. When you informed me about buying my materials from the company you suggested online I did some investigation work on the company and they are selling products well below recommended retail prices, REC and SMA will be looking in to this as they don’t want their products discounted online showing Trade prices as retail prices we all need to make profit in every business.

And we were doing so well up to that point ...... probably best I don't comment any further on this bit to avoid using words like "protectionism", "disgust", "typical", "here we go again", "exactly what the PV'ers on here are trying to protect households from", and so on, and so on.

This isn't my first rodeo when it comes to 'chatting' with installers, for an example of the quality of advice sometimes posted, have a read of the helpful and informative advice :doh: given to me by Caan (an infrequent poster and PV installer / PV employee) on this thread when I spotted two Hanergy insiders posting camouflaged spam.

Mart.

tunnel

Love_Solar wrote: »

When you informed me about buying my materials from the company you suggested online I did some investigation work on the company and they are selling products well below recommended retail prices, REC and SMA will be looking in to this as they don’t want their products discounted online showing Trade prices as retail prices we all need to make profit in every business.

We PV'ers have used that companies prices as a guideline for over 3 years now, if there was a problem with their prices, and bear in mind their prices are retail then it would have been shut down long ago. I believe it's more a case of sour grapes for being ratted out.
I personally know of one guy who had a 4kWp system installed for £3995 inc VAT...still say their prices are too low?

Love_Solar wrote: »

Solar PV Price Guide for consumers
2 KW system from £3000.00
3 KW system from £4000.00
4 KW system from £5000.00
plus VAT 5%
For a standard string inverter

You may be correct for the 2kWp system and now your 3kWp has strangely dropped £1k from your original post below

Love_Solar wrote: »

I would recommend the following a 3 kW system with using the solar edge inverter and optimisation units, this will give you full monitoring online and better warranty as this is twelve years as standard and can be extended to twenty years for £156.00
You will still make the same saving in house as the 3.99 kw system. Use the standard 250 or 260 watt solar panels and this system should cost you no more than £5000.00

I'd say the prices above would be nearer the mark if they included VAT but even then they'd be top end for the system size quoted.

ely_ellis

Just my 2p's worth on system prices.
At the end of June I had a quote for 16 x 250w panels with built-in Solaredge optimisers and inverter for £5200.
I did pay a little more as I wanted different panels, stand-alone Solaredge optimisers and an iBoost.

hethmar

Head spinning