PV- real world figures

denismc

I have been watching the price of domestic PV systems fall over the last number of years and I am now considering installing some in my home.

There is a lot of information on the internet which is useful but I would like to hear from people who have installed domestic PV systems in the last few years.
So if people could describe their system a little bit and maybe let us know if they found it to be a good investment i.e did it reduce your electric bill?

Thanks

rolion

denismc wrote: »

I have been watching the price of domestic PV systems fall over the last number of years and I am now considering installing some in my home.

There is a lot of information on the internet which is useful ....

Not been labelled a smartie... but did you read any of the topics here !?
What do you think ?

denismc

rolion wrote: »

Not been labelled a smartie... but did you read any of the topics here !?
What do you think ?

Yes I did, Did you read my post?

unkel

denismc wrote: »

Yes I did

Did you really?

Just read rolion's thread about his PV install. This thread has been on the first page of this forum for a very long time. It will give you all the answers your are looking for.

And a short answer: of course it will reduce your electricity bill. But the return on investment is extremely poor. Many decades.

denismc

Ok
Apologies if I sounded a bit snotty.
I did read that thread and while its very helpful, I am not an engineer. That thread is about a self built system and involves microgeneration and selling back to the grid. Some of this stuff might be straight forward to you guys but a lot of people searching this forum are not hobbyists but are looking for more of a standard installation.

I suppose what I am trying to get at is having a thread where people can see peoples net savings over a year or multiple years.

unkel

I'm like you, Denis. I would only look into a system that is fully installed for me. The unfortunate news is that you will save a few hundred but it will cost you many thousand. Solar PV is at the moment the last thing you should focus on.

If you want to be green and want to save money, buy yourself an electric car. Massive savings to be had. And if your household uses lots and lots of hot water, get a solar tube hot water system installed.

noel100

I am looking at 5kw system for €2600
Extra is the racking system for the roof
And abour €400 euro delivery from UK

18 x JAM6-K-BK-60-280-4BB-F35 JA Solar 280W Mono SK All Black 35mm

1 x SOL-5.0-4G-DT Solis 5.0kW 4G Dual MPPT - Single Phase

Should produce 5370kw electricity per year in midlands at optimal direction and angle.

If you can use the 5370 units at 0.16kw
Would equal €859 a year so should be paid off in 5-6years allowing for extras (electrician + cert) and a smart meter etc.

freddyuk

You do not need a 5kw inverter for 5kwp of PV input and you do not need twin MPPT unless you need to avoid shading or have different aspect roofs. Normally inverter is 80% of total installed capacity because you rarely exceed the limits of the system and even then only briefly so not economic and inverters are more efficient running at near capacity. Keep the money towards a replacement inverter in 5-10 years possibly.
You do not need a smart meter which is very expensive unless you are being paid for export which you will not be. Just have a generation meter to measure your total input.
You will not use 100% of your generation so you need to have a diversion system to maximise on site usage as export is freely given away.
PM me if you want help with UK supply as shipping racking systems is not viable !!

unkel

noel100 wrote: »

if you can use the 5370 units at 0.16kw
Would equal €859

Your sums are not realistic, don't fool yourself.

1. 5370 is extremely optimistic of the midlands

2. if you can use the 5370 units? Almost certainly not. How are you going to use 4kW coming into your house on a sunny day? A lot of it will be lost (go to the grid for free). If you have an EV that's always parked at home during the day, than maybe you will get close

3. it is not EUR0.16/kWh. Most of your production is competing with night rate, which is EUR0.0665/kWh

So your savings are probably more like 4000 units production. Half lost (this is already optimistic), other half at 6.65c, so about EUR250 per year (unless you have the EV parked at home during the day)

rolion

denismc wrote: »

I have been watching the price of domestic PV systems fall over the last number of years and I am now considering installing some in my home.

Just an email received this morning from a PV supplier:

Conor20

€3k for a 5kW system is a pretty decent price! I paid about €4300 for a 2.2kW system about 9 months ago. I added four more 285 watt panels for €200 a pop to the system last month. It's generated 1935kWh so far in those 9 months. You can read the numbers I calculate for our savings here but as you'll hear from everyone, it's really about how much of the energy you use. We have two young kids in the house all day, and an electric car so we consume a lot of energy during the good solar hours. We also conume a lot of hot water the PV system generates via an iBoost hot water diversion unit. I think you could work out what you'd save by working out:

• You're day time electricity consumption in kWh x your daytime kWh rate
• Your Night time consumption (dishwashers, etc.) that you could move to times of "free" solar x the night kWh rate
• You're hot water consumption x your gas kWh rate / (or if you heat water electrically, electric immersion = night kWh rate / electric shower = day kWh rate)

That would give you a ballpark. To see what a PV system of a given size at the orientation of your roof will generate where you live, the NREL PV Estimation tool is very good.

unkel

Conor20 wrote: »

€3k for a 5kW system is a pretty decent price!

Not all material is included and he is installing it himself.

unkel

Conor20 wrote: »

To see what a PV system of a given size at the orientation of your roof will generate where you live, the NREL PV Estimation tool is very good.

Cheers. A 100% south facing 4kW install in Dublin gives you a bit under 3.4MWh per year. In the midlands about 3.2MWh per year, so 5kW panels in the midlands will give no more than 4MWh (not the 5.4MWh noel100 is hoping for)

737max

Red Dwarf's Kryton on Fullycharged youtube channel had an interesting report on his powerwall and pv solution.

he was charging his tesla and leaf off it when he could too.

all I could think was that a certain element of society who are in to organized crime will be able to sell the panels like they used to sell lead and copper off rooves and the powerwalls are very transportable/transitable/hi-aceable.

unkel

Shure there's no copper in them roof plates, boss?

Gumbo

My 3kw system was generating 3.3kw the other day for a period.
I haven't got the app yet as I haven't got wifi in the house just yet so I'm just checking occasionally while looking at the site works.

I am finglas, south facing so be interesting to see how it fairs out.
Immersion divertor to be fitted next week all going well.

Effects

kceire wrote: »

My 3kw system was generating 3.3kw the other day for a period.

What type of inverter do you have and what's it's rating?

Gumbo

Effects wrote: »

What type of inverter do you have and what's it's rating?

I'll check tomorrow.
3.432kw today for a period.

rolion

kceire wrote: »

I'll check tomorrow.
3.432kw today for a period.

I highly recommend checking the system.
There is no way that a 3Kw power PV system can generate 3.432KWh at "a period" of time ! I'll be worry about cabling,inverter and fuses.
I hope you dont confuse generated power "up to now" with instant power "right now"

Gumbo

rolion wrote: »

I highly recommend checking the system.
There is no way that a 3Kw power PV system can generate 3.432KWh at "a period" of time ! I'll be worry about cabling,inverter and fuses.
I hope you dont confuse generated power "up to now" with instant power "right now"

I'll check today.
I'm just going by what is displaying on the invertor screen.
It could jump from 3.4 to 2.5 to 3.1 in a matter of seconds (obviously as light hits the panels).

I haven't moved in yet so have not got the system connected to the wifi to monitor just yet.

I do know the immersion Diverter is a My Energi Eddi unit.
http://myenergi.uk/product/eddi/

Ill get the invertor details soon as im there about mid day.

Gumbo

My invertor is a Trannenergy SGN3400TL unit.

Effects

kceire wrote: »

I'll check tomorrow.
3.432kw today for a period.

I didn't know that a 3Kw system could produce more than that but thought maybe there was something that I wasn't aware of.

I had read that inverters can handle 130% of their rating, or something similar.

freddyuk

Has the Trannnergy SGN3400TL unit got a certificate for connection to the Irish network? If not you can be disconnected by ESB as you must have correct settings for Ireland and you must have disclosed this on your NC4 form? Please confirm as we need a database of approved inverters. I very much doubt this Chinese inverter is legally installed under the daft special Irish regulation.
If the inverter has more watts connected than the wattage rating then it will just de rate to it's maximum output.

If the voltage from the PV exceeds the maximum rating (580v) then the inverter will blow. I presume you have 2 parallel strings.

Gumbo

freddyuk wrote: »

Has the Trannnergy SGN3400TL unit got a certificate for connection to the Irish network? If not you can be disconnected by ESB as you must have correct settings for Ireland and you must have disclosed this on your NC4 form? Please confirm as we need a database of approved inverters. I very much doubt this Chinese inverter is legally installed under the daft special Irish regulation.
If the inverter has more watts connected than the wattage rating then it will just de rate to it's maximum output.

If the voltage from the PV exceeds the maximum rating (580v) then the inverter will blow. I presume you have 2 parallel strings.

Fully supplied and installed by a large solar panel company. Commissioned by them, certified by them and registered with ESB through my MPRN.

Effects

Effects wrote: »

I didn't know that a 3Kw system could produce more than that but thought maybe there was something that I wasn't aware of.

Standard Test Conditions: 1000W/m² @ 25°C
Output is ~20% of input.

I often get panels producing above rated once I've removed the inverter and associated losses from the equation.
It's advised with a lot of controllers and inverters to only load them to 80% rated capacity because they will spike with cloud lensing and cold temp uprating (usually happens at the same time).

It's entirely possible for 3kW peak Pv to produce 3.3kW
One of my systems regularly produces 10% over rating (at the panel, not the inverter)

freddyuk

kceire wrote: »

Fully supplied and installed by a large solar panel company. Commissioned by them, certified by them and registered with ESB through my MPRN.

Can you ask them for a copy of the certificate with Irish settings? It is not on the manufacturers website

Gumbo

freddyuk wrote: »

Can you ask them for a copy of the certificate with Irish settings? It is not on the manufacturers website

I can indeed. They are back in 2 weeks to fit immersion divertor and set up the wifi monitoring. Just waiting on my plumber to fit my new cylinder and heating system.

Effects

Sir Liamalot wrote: »

It's advised with a lot of controllers and inverters to only load them to 80% rated capacity because they will spike with cloud lensing and cold temp uprating (usually happens at the same time).

I've got a 1.74 kW panel system but a 1.5 kW inverter supplied by the PV company.
So I should really be looking at 2.1kW inverter or thereabouts?

air

The underrating only really applies to voltage limits, not to power limits.
It is normal practice to overrate the PV install to the inverter - eg 5kW of panels into a 4kW inverter.
In practice very little output is lost to inverter clipping in such a scenario as the number of hours of 4kW+ output throughout the year will be negligible.
So your company didn't do anything wrong Effects.

Effects

Ah ok. I was worried that the inverter wouldn't handle that much power or would only output at the lower 1.5kw.

air

Effects wrote: »

Ah ok. I was worried that the inverter wouldn't handle that much power

It will handle it fine.

Effects wrote: »

or would only output at the lower 1.5kw.

It will be capped at the lower 1.5kW figure, but in practice this isn't a big deal. For example if you had a 2kW inverter instead, the number of hours a year your inverter would output 1.75kW would be few and far between - and it's only an extra 250W in any case!

As long as the voltage is within spec and the inverter has current limiting it's fine.

PWM controllers and cheapo GTIs will not have input limiting protections which is catered for by 20% overhead on the array.

wexfordman2

Saw this, thought it might be of interest, albeit it's in northern Ireland and they have a feed in tarrif I believe

http://www.automatedhome.co.uk/carbon-footprint/going-solar-part-5-our-pv-systems-actual-generation-figures-after-first-full-year.html

Based on last year's generation, he expects payback in under 6 years

rolion

wexfordman2 wrote: »

Saw this, thought it might be of interest, albeit it's in northern Ireland and they have a feed in tarrif I believe

http://www.automatedhome.co.uk/carbon-footprint/going-solar-part-5-our-pv-systems-actual-generation-figures-after-first-full-year.html

Based on last year's generation, he expects payback in under 6 years

Thanks for the link.

My plant has generated almost 4MWh, in one year / 12 months !
Does that measn ALL has been used by my towards my own benefit !??
No,some of it went FOC to supplier or wasted.

So,my ROI has been dealt with ... unless you have a system in place to monitor / alert / divert so to maximise return on the PVs generation,i consider any ROI to be compromised !

Effects

Got a call from an ESB engineer today. He was supposed to tell me which pole to connect for the house's new connection to but he wasn't actually sure.
Anyway, he said I'll just get a standard meter. Energia doesn't do smart meters or import/export meters. Any excess energy generated by the panels will just sit at the panels and won't go back to the grid.

rolion

Effects wrote: »

Got a call from an ESB engineer today. He was supposed to tell me which pole to connect for the house's new connection to but he wasn't actually sure.
Anyway, he said I'll just get a standard meter. Energia doesn't do smart meters or import/export meters. Any excess energy generated by the panels will just sit at the panels and won't go back to the grid.

Its not Energia that suplies and / or install the meters !
Is ESB all day...I'll pass you the numbers to call later.
Did you register the inverter with ESB by filling that form !?



Ask for at least a digital type and do not accept one with spinning wheel.



Any excess of PV electricity will be going directly in to Mr Grid, with zero pay back to you.

Have fun...

Effects

Effects wrote: »

Any excess energy generated by the panels will just sit at the panels and won't go back to the grid.

An engineer said that? :rolleyes:

Unless the meter defies physics the counter just stops but the energy doesn't.

Effects

Yeah, I was a bit scepticle of some things he had to say. He was calling me to tell me which pole to duct to but then didn’t actully know somsaod he’d come back to me. Still waiting!

So I presume the import/export meter will cost more? Probably a good idea to have it if they bring in a feed in tariff at some stage.

I wouldn't fit an export meter for what they charge for it to meter what you donate them. To each his own....

rolion

Effects wrote: »

Yeah, I was a bit scepticle of some things he had to say. He was calling me to tell me which pole to duct to but then didn’t actully know somsaod he’d come back to me. Still waiting!

So I presume the import/export meter will cost more? Probably a good idea to have it if they bring in a feed in tariff at some stage.

What kind of meter you have currently !?

There is not and neither will be FIT for small people like us...

Effects

No meter at the moment as it’s a new build.
So you don’t think there’ll ever be a FIT?
How can government be pushing renewables and energy saving yet not offer any help?

gally74

Effects wrote: »

Got a call from an ESB engineer today. He was supposed to tell me which pole to connect for the house's new connection to but he wasn't actually sure.
Anyway, he said I'll just get a standard meter. Energia doesn't do smart meters or import/export meters. Any excess energy generated by the panels will just sit at the panels and won't go back to the grid.

that's not totally true, you can request a day / night or export meter if you want,

rolion

Effects wrote: »

No meter at the moment as it’s a new build.
So you don’t think there’ll ever be a FIT?
How can government be pushing renewables and energy saving yet not offer any help?

If is a new build then the buildeer has to get a meter for you !?
Get a digital on,same as mine in a prvious photo.

I dont think versus what will be ... is same diffrence more or less like my PV outputs today,from 4KW to 400W over couple of minutes !

The Guvernment is pushing !??? Really ,i just dont see it,where ?
SEAI are doing a great job in givng grants for a better home but no words to open again the FIT prohramme for PVs. Is between you ,your panels and your consumption pattern(s)...

Enjoy it

Effects

rolion wrote: »

If is a new build then the buildeer has to get a meter for you !?

Connections with utilities is up to me to look after. Builder puts in meter box and duct to pole.

rolion

If is a new build, i will go with an export / import meter.Future proof.
Is easy now to hide the cost now between so many expenses rather than later, when the same €400 it will look harder and heavy and lots of pain to change it !!!
But,that's me.

Effects

rolion wrote: »

Is easy now to hide the cost now between so many expenses rather than later.

If only it was that simple!
Engineer make a big mistake and I’m now struggling to cover the cost of drainage connection.

Gumbo

I have a 3kw system.
South facing in north dublin.

Between 10am and 1pm yesterday my house was off grid.
My system
Powered the house base load, washing machine cycle and also a full 200L cylinder of hot water.

I only had my divertor fitted on Wednesday so still beginning to track the Use.

This is what electrically off the grid looks like:



This is what exporting to the grid looks like:



Sorry for being pedantic.

freddyuk

I have just wired up 12 old rolls batts which were off a job. Used a cheap inverter and was off grid during 10 hours of power cuts. Had heating, Internet (until their power failed!) lights, freezer, fridge freezer, TV, so we're cosy. Not a proper install just Jerry rigged but worked like a dream. Wife is convinced it is worth getting the proper kit now so will be going with grid backed system to begin with and find a supplier that does not charge for low users. Spare solar will then charge batteries not be given away free until we have surplus.

I haven't had a power cut for 6 years. I always laugh when sparkies try to convince me conventional power is more reliable than renewables.

Nice find on the Rolls.

a148pro

kceire wrote: »

I have a 3kw system.
South facing in north dublin.

Between 10am and 1pm yesterday my house was off grid.
My system
Powered the house base load, washing machine cycle and also a full 200L cylinder of hot water.

I only had my divertor fitted on Wednesday so still beginning to track the Use.

Interested to hear more updates on this Kc as considering similar