Project Solar - am I getting ripped off? HELP!!

dan318064

Zarch wrote: »

Has he provided FIT figures and usage calcs etc? How many years does it say it will take to break even?

For 5kWh system without the battery and at a £5.5k install price i'd say around 9 to 10 years based on current FIT figures. Obviously, how much you consume of what you use may affect, but not by too much.

Sorry, missed the crucial bit off!! He said:

The system size will be 4.96 kwh we can actually say 5 kwh. (5000kwh) and 6.5kwh energy storage with our Q cell GEN5 panels theres a 19.3 performance increase to (5965Kwh), the hybrid DC system will add up to 50% more as the energy save to use at nights will add to your total generation . (5965kwh plus 50% 2982kwh added by battery system.

Total system generation per annum is 8947kwh
The current FIT rate is 3.96p per kwh and 4.91p per kwh export, I have attached fit cart. Export payment is deem at 50%.

FIT PAYMENT 8947kwh @ 3.96p £354
50% EXPORT PAYMENT 4473kwh@ 4.91p £219
On a 5kwh solar pv system and 6.5kwh hybrid your annual FIT payment will be £573
Your current electric usage is 9667kwh at 14.89p per kw (£1,439 annually) the system will save you up to 65% of your electric £935

SAVINGS AND FIT Payments annual £1,508 the margin of error is 7% of this total, savings and FIT Payment is £1,403
We will take out the voltage Optimisation, Please find below information on the boiler minder.
You will brake even on investment in year 6.




BOILER MINDER INFO.

The new Energy Minder Auto is a new generation domestic boiler controller that is designed to reduce the cost of running a domestic central heating system.
Specially developed software provides a self-learning controller that regulates the firing cycle of the boiler to match demand without any user intervention. Any change in the boiler output temperature made by the user is automatically tracked and catered for by the Energy Minder Auto software.

Electronic sensors fitted to the flow and return pipes of the boiler provide the controller with the data required to establish the central heating demand, including individual flow and return temperatures, user operating temperature and temperature response times. The system employs a unique algorithm which analyses this data and modifies the boiler firing cycle accordingly.

The result is a domestic boiler controller that is self-adaptive, requires no commissioning, is simple to install and automatically responds to any seasonal adjustments made to the heating system by the user.

Benefits include an increase in central heating system efficiency, reduced heating fuel consumption, reduced CO2 emissions and reduced heating fuel expenditure.

Mains Supply - 240V AC 50Hz 1Ph
Consumption - 3VA
Switching Mode - Volt Free
Switching Current - 3A
Boiler Suitability - Single small domestic boiler
Standard Equipment - Main Controller, Flow Sensor, Return Sensor, Mains Harness
User Adjustments - Active/Bypass Switch
Viewing Indications - Current Mode, Systems Temperatures

pinnks

Perhaps it's me but this all reads as confusing nonsense - sorry - and still makes me worry somewhat about the quoter's motives.

First, a system has a certain size - Wp per panel times number of panels. The quote says 16 x 310 = 4,960Wp, so just under 5Kwp. This is not an indication of how much the system will actually generate and the concept of some 19.3 performance increase by a certain type of panel is frankly nonsense. A panel has a measured Wp and that is that. Some panels are more "efficient" but all that means is that you get more Wp for the physical size of the panel. So one panel may be rated at 250Wp while another panel of the same size might be 310Wp. Put 16 of one of those on your roof you get 4kWp; 16 of the others 4.96kWp.

Also, suggesting battery storage will add to your generation is total twaddle. The panels will generate a certain amount and that will be used in one of three ways: Go into the battery for use later; be used now; or be exported to the grid. Your FiT payments are based on what comes off the roof, once it is converted into AC - nothing else can feature and if someone suggests differently they are either living on a different planet or worse!

Your system is unlikely to generate the Wp in kWh. I have 5.25kWp and generate about 4,500kWh per year. I would suggest that you would generate a similar ratio but that depends on the orientation of the roof(s), pitch and shading. So, I would guess perhaps 4,000kWp per year would be reasonable but Mart and others will have more knowledge than me on that.

So, based on 4,000kWh per year FiT income of about £160 per year plus export of perhaps £100 making £260 in total. Reckon on own consumption of perhaps £150 per year, plus whatever saving the battery would give you but that will be less than your current total consumption. I don't know but perhaps you could save 75% of current overall leccy costs (excluding the daily standing charge)? I see the quote suggest about £935 saving at 65%. Perhaps that is reasonable but add £260 total FiT to that and you are well south of their estimate.

What they say about the iBoost is, in my opinion total rubbish. All these devices can do is power purely resistive loads as I mentioned before. Unless you have a hot water tank with immersion element a diverter will be a total waste of money.

What is described as a boiler minder may or may not be an interesting product - I have never heard of the concept - but has nothing whatsoever to do with a PV system and nothing to do with an iBoost or similar device. You may or may not think the investment is worth it but can decide that separately to your decision about PV as they are mutually exclusive things.

Although I am a fan of PV I cannot see that you would break even after 6 years unless we hit hyper-inflation and FiTs go sky-high. If you reckon with about £260 FiT plus £150 leccy saving without battery you have £410 per year to repay your investment. If you take the battery that could increase to about £1,100 but could be less. If you reckon with £1,000, then you at 9 plus years.

But do you really guzzle nearly 10,000 units of electricity per year? The most we have used in the last 10 years was about 7,500kWh with old CRT TVs, set-top boxes, old fridges etc, tungsten lighting and so on. Now, with new devices, TVs, LED lighting, energy awareness and so on we are now down at about 3,000kWh per year of which we supply about half from our roof. So if we had a battery the most we could save would be about 1,600kWh at say 15p or £240 per year if the battery gave us everything all year round and that is not likely to happen. If we cleared £200 additional savings with a battery I would be happy. So, if others are right and the battery element is £3k, you would need 15 years to repay the battery part - ignoring the fact that the battery may need replacing after 10 years or so.

So, I still have concerns about the quoter and their real motives if what you have copied/pasted is in context.

Sorry if this sounds a bit like a rant, I am not getting at you but am beginning to wonder whether you need that barge pole to hand.

dan318064

pinnks wrote: »

But do you really guzzle nearly 10,000 units of electricity per year?

Shamefully we do use almost that amount. Our leech bill from SSE last year showed an annual usage of 8,982.00kWh. All the PV installers that we have had over to quote so far have been shocked at that. To put it into context; we both work from home, I run computers 24hrs a day as I have contact backups going on through the night and am working on them during the day. I have e servers running 24/7 but this is something I need to address and change my working practice to match my ethics.

To also aid any comments on how much the system may or may not generate I should probably put us on the map. We live in SE England (London) so have a relatively high amount of sunny days to help us along plus we have a loft conversion with a flat roof that is completely unobstructed by any trees or buildings shade wise. We are planning to have 8 panels on there.
Our rear extension is south facing with the roof facing South / South/West with a pitch of 40 degrees with 5% shade . We're planning to have another 8 panels on there.
I don't know whether this means we'll stand slightly m ore of a chance of attaining those kind of figures quoted but it seemed to make sense in pointing out that we should have a fairly good aspect for solar use.

Martyn1981

Like pinnks I have some negatives, but nothing against you. Also whilst I agree 100% with pinnks post, I think I can do a tiny bit of polishing now with your last post and roof data.

Firstly, generation. London, south facing and 40d pitch is an excellent set up, so 1,000kWh/kWp might be doable, even 1,100 some years.

Have a play with PVGIS (see PV FAQ's sec 5 (link in my auto sig)) and see what it says.

I think 4,500kWh's pa will be reasonable, with 5,000 possible, and even 5,500 on a good year, but see what PVGIS says.

Next, total gen, panel efficiency etc etc. As Pinnks has explained, higher panel efficiency simply means that 1kWp of panels will take up less roof space, but it is still 1kWp of panels. So the crucial figure is the total kWp on your roof, not the efficiency of those panels.

Batts will not increase your generation, that's entirely false. In fact (boring bit here) they will lower your generation a tiny bit, as there will be a small amount of loss on the leccy that goes into then back out of the batts, and as this occurs before the FiT meter (TGM - total generation meter) then that will reduce what the TGM records:-

EG [Just a made up example] 5,000kWh's of generation. 2,500kWh's gets used at the time of generation or gets exported because the batts are full, so the TGM 'sees' all 2,500kWh.

2,500kWh's go into then back out of the battery, with a 10% loss (250kWhs), so when you draw down those units, the TGM will only 'see' 2,250kWh's.

High leccy consumption - you've explained why, so that seems fine, and PV will therefore make a lot of sense, as the more you consume, the greater the returns. Hard to say if the batt will be value for money, but you are certainly one of the consumers best placed to try.

So total income and savings.

Let's say 4,500kWh's pa, just to prevent being overly optimistic and to allow for some batt losses:

FiT 4,500 @ 3.93p/kWh = £176.85
Export 4,500 @ 50% deemed @ 5.24p/kWh = £117.90
Sub total £294.75. I think we can call that £300.

Leccy savings, now these are tricky, but with high daily consumption you will use more and export less, and the batt will mean even less export, apart from great days like this summer when there may still be too much generation for the batts.

So I'm going to stick my neck out and suggest 3,500kWh's or possibly more, of that 4,500kWhs.

3,500 @ 14.89p/kWh = £521.15

All in, somewhere around £800 pa?

I'm actually a bit shocked at that, and have gone back to double check (Pinnks have I made a mistake, that seems extremely high?)

If you can get closer still to £8k, then that's a 10yr payback. The PV should be good for 30+yrs, inverter less, so make sure you have a long (extended) warranty. The batt will presumably be good for 10yrs, and hopefully 20yrs, but I suspect a replacement in 10yrs+ will be far, far cheaper.

I think it's looking reasonable, unless I've gone off track somewhere.

Martyn1981

dan318064 wrote: »

I don't really know how these forums work but I hope it's ok using you as a soundboard? I don't really know enough about this as it's early days for us but I hope you don't mind me garnering your opinion as its been invaluable so far.

I've always assumed that that's exactly what these forums are for, especially given the money saving side.

Also, we have all been in your position, knowing very little and asking for help and guidance (a virtual hand holding exercise), so we are just paying it forward.

Keep asking, pondering and researching until you are comfortable with a decision be it a yes or no. And golden rule on here, particularly with PV, there are no stupid questions, it's new kit and tech to you, and you only learn by being open to discussion.

EricMears

Martyn1981 wrote: »

Have a play with PVGIS (see PV FAQ's sec 5 (link in my auto sig)) and see what it says.

Since some of the panels will be on a flat roof and others on a sloping one, you'll need to run PVGIS twice - once for each set - then add the results together.

And I too agree that some of the extras being offered would be a waste of time (and money !). Voltage optimisation is seldom appropriate in a domestic setting and any sort of power recovery to an immersion heater won't work unless you have an immersion heater. As for the boiler management software, unless he can explain it in simple language (without violating the Laws of Thermodynamics) then I'd assume it's another unnecessary addition. Stripping out those items would probably result in a reasonably competitive quote - but I'd still urge you to get another quote (or several) so that you really know just how competitive it is (or of course accept an alternative).

pinnks

Mart,

Much more accurate numbers than my tired brain wanted to work out last night and given the constant load from the servers I think you are right about potential savings.

My brother runs a similar set-up but is not (yet) on PV and we have often chatted about his base load - yes, I know I'm "sad". While the servers guzzle a lot over a 24-hour period they are still "relatively" low power. Each one may only consume 200W but put 4 or 5 together you are still ending up with an extra 1kWh based load. A 5kWp system would easily cover that for a large part of the day and on any reasonable day between say March and October would also put a good amount into the batteries. How often would one get the hours of darkness provided fully from the batteries? Perhaps 80% of those March to October days? And over the remainder of the year virtually everything produced would be used directly or via the batteries.

So, with a relatively high but constant baseload and batteries I think you might well be right to think 3,500kWh leccy savings and £520 per year.


As you say, total per year then around £800. But that is still only half of the £1,500 projected by the quote - but I think we are probably all agreed that that is based on incorrect maths and assumptions.


I would love to save that amount of import but would not like that high usage...:beer:

Martyn1981

Cheers pinnks, I was genuinely surprised at the £800 figure. All the steps seemed to make sense from A to B to C etc, but when I typed £800 my brain went 'no way!'

I don't want to mislead by being overly optimistic, but I think the £800 should be near the bottom of the range, as generation might be a bit better, and export lower.

Certainly shows where PV and storage can work, and viability might start to creep in.

pinnks

Indeed.

Out of interest for the OP, my generation yesterday was 30kWh (my max possible would be about 32). Diverted 3.5kWh to hot water; own consumption 5.5kWh; imported 2kWh and exported a whopping 21kWh. :T

Compare that to 15 March this year which was a couple of kWh below expectations: generation 11.5kWh; diverted 6kWh (water and UFH); imported 5.5kWh; exported less than 1kWh

And December 26th, bang on expectation: generation 4kWh; diverted 1.5kWh (water and UFH); imported 11kWh; exported 0.2kWh :(

Whether these numbers help the OP is a good question but three random days, 2 of which are more typical for the time of year than our current super-PV-weather :beer: