Domestic solar PV quotes 2018

air · 09-09-2019 2:32pm

[Deleted User] wrote: »

Yeah so you advise people to dump energy then ? that's fantastic advice.

Hey everyone, air says it's better to buy loads of Solar PV to dump it.

I'm suggesting that you haven't a bulls notion about, or any experience with small wind energy in Ireland or anywhere else. In light of that fact it might be best if you held off on recommending it.

Yes, economically it can make perfect sense not to chase every last kWh of potential production in a PV system, especially in the current situation where there is no FIT.
Call it dumping if you like.

Even off grid an East / West system is usually more desirable than a Southerly one, despite the fact that you're "dumping" potential units every day.

You've no experience with PV either and yet you've very strong opinions on it.

09-09-2019 2:37pm

air wrote: »

I'm suggesting that you haven't a bulls notion about, or any experience with small wind energy in Ireland or anywhere else. In light of that fact it might be best if you held off on recommending it.

Yes, economically it can make perfect sense not to chase every last kWh of potential production in a PV system, especially in the current situation where there is no FIT.
Call it dumping if you like.

Even off grid an East / West system is usually more desirable than a Southerly one, despite the fact that you're "dumping" potential units every day.

You've no experience with PV either and yet you've very strong opinions on it.

Yeah I do have a strong opinion on it, it's great even in Ireland but without a FIT it's not much good to most people unless they run a heat pump in Summer lol.

Sorry boss, can't come to work tomorrow, the weather forecast says it's to be sunny so I have to stay at home to manage the energy consumption of the house so I can use all the solar I paid for lol

KCross · 09-09-2019 2:45pm

Deleted User wrote: »

Yeah I do have a strong opinion on it, it's great even in Ireland but without a FIT it's not much good to most people unless they run a heat pump in Summer lol.

Sorry boss, can't come to work tomorrow, the weather forecast says it's to be sunny so I have to stay at home to manage the energy consumption of the house so I can use all the solar I paid for lol

You dont size a PV system to use it all. You size it to use as much of it as you can (limited to roof space and budget) across the year and that will also mean wasting some of it to the grid.

For instance, it might make sense to put in a 9kWp system and waste more during the summer but that 9kWp is then providing you with more energy in the winter when a smaller system would be barely powering up the inverter.... its a balancing act.

And then further complicated by using an east-west orientation so the headline kWp figure is only part of the equation.

air · 09-09-2019 2:45pm

[Deleted User] wrote: »

Yeah I do have a strong opinion on it, it's great even in Ireland but without a FIT it's not much good to most people unless they run a heat pump in Summer lol.

Sorry boss, can't come to work tomorrow, the weather forecast says it's to be sunny so I have to stay at home to manage the energy consumption of the house so I can use all the solar I paid for lol

I never suggested over sizing an array for everyone, I'm just making the point that it can make sense for some applications.

The heat pump is a perfect example, well done.

A 9kW array would produce over 1kW for a good number of hours in Autumn and Spring that could be used to run a small ASHP and provide some effective zero carbon space heating for example.
I'm planning to do just that myself soon for my home office.

I admire your self confidence pontificating vociferously on subjects with which you have little or no understanding of.

09-09-2019 2:57pm

air wrote: »

I never suggested over sizing an array for everyone, I'm just making the point that it can make sense for some applications.

The heat pump is a perfect example, well done.

A 9kW array would produce over 1kW for a good number of hours in Autumn and Spring that could be used to run a small ASHP and provide some effective zero carbon space heating for example.
I'm planning to do just that myself soon for my home office.

I admire your self confidence pontificating vociferously on subjects with which you have little or no understanding of.

Ok well if you want to give free energy away then that's up to you or if you want to go spending more money just to use that otherwise dumped energy go ahead but don't go advising others to spend big bucks to dump energy or go spend thousands on a heat pump.

9 Kwh. that would be a lot of unused energy in Summer. Without a FIT.

And it's great we have wise people to tell fools like me to go spending thousands to save some Kwh but dump the rest.

air · 09-09-2019 3:12pm

[Deleted User] wrote: »

Ok well if you want to give free energy away then that's up to you or if you want to go spending more money just to use that otherwise dumped energy go ahead but don't go advising others to spend big bucks to dump energy or go spend thousands on a heat pump.

9 Kwh. that would be a lot of unused energy in Summer. Without a FIT.

And it's great we have wise people to tell fools like me to go spending thousands to save some Kwh but dump the rest.

It's 9kW not 9kWh.
You could have a look at the difference between power and energy as starting point in your renewables education.

I never advised anyone to do anything, unlike yourself.

I merely provided some reasoned argument why an oversized array might make sense for some people.

I'm not in the business of splashing around one size fits all advice from a position of ignorance on the particular person's priorities.

09-09-2019 3:51pm

air wrote: »

It's 9kW not 9kWh.
You could have a look at the difference between power and energy as starting point in your renewables education.

I never advised anyone to do anything, unlike yourself.

I merely provided some reasoned argument why an oversized array might make sense for some people.

I'm not in the business of splashing around one size fits all advice from a position of ignorance on the particular person's priorities.

Yeah yeah I know the difference between Kw and Kwh I talk a lot about Kwh in the EV section of Boards , thanks all the same for trying to educate me.

Try insult me more , I love it, you keep showing how obnoxious a person you are. So keep showing it.

air · 09-09-2019 4:08pm

[Deleted User] wrote: »

Yeah yeah I know the difference between Kw and Kwh I talk a lot about Kwh in the EV section of Boards , thanks all the same for trying to educate me.

Try insult me more , I love it, you keep showing how obnoxious a person you are. So keep showing it.

I haven't insulted you once, but I appreciate that English may not be your first language.

You've suggested domestic micro wind which is basically ridiculous for 99.9% of residential properties in the country. Even then is unlikely to provide a payback anything like PV, with or without subsidy. It's also relatively high maintenance. As far as I can tell you have no direct or indirect knowledge about it.

You have no experience with PV or really any feel for how it operates in terms of production and consumption and yet you're advising people on what they should or shouldn't do with no argument to support your position.

In conclusion I don't think you are adding anything useful to the thread.

reklamos · 09-09-2019 9:30pm

I can see this happening in ROI soon the way some PV installers pushing their products and we don't have FIT yet. This could do a lot of damage to PV uptake
https://www.bbc.co.uk/news/amp/uk-england-49566130

10-09-2019 7:30am

KCross wrote: »

You dont size a PV system to use it all. You size it to use as much of it as you can (limited to roof space and budget) across the year and that will also mean wasting some of it to the grid.

For instance, it might make sense to put in a 9kWp system and waste more during the summer but that 9kWp is then providing you with more energy in the winter when a smaller system would be barely powering up the inverter.... its a balancing act.

And then further complicated by using an east-west orientation so the headline kWp figure is only part of the equation.

The excess of a 9 Kwp System in Summer would be much more than I could use but It could run dishwasher and washing machine etc during the day when she insists to use it sometimes instead of the night, the dryer etc but the dryer actually uses very little as it's got a heat pump. It would run the well pump, septic tank pump and for cooking.

Though in reality I might be better off to get a battery and charge it up on night rate and use that during the day.

When I have a 60+ Kwh EV I would very much like to be able to use the work electricity to power the house, we're some time away yet from having a CCS V2G system.

We're getting someone out to access the house for a water sourced heat pump because the heating needs replacing and I want to move from oil, the 60 Kwh in the EV would help a lot to power it and a COP of around 7 is very attractive what it turns out to be in my house which isn't an A rated air tight house would be interesting to find out but a FIT system where all the excess goes to the grid and bought back in the colder months would be great so I wouldn't be as concerned about the air tightness and insulation of the house.

In reality I could probably fit 20 Kwp , roof and garden but single phase is the limitation.

Batfink69 · 11-09-2019 1:18pm

Hi All,

Just bought a 2.7kw system; no battery or grant and hoping to self install mostly myself to keep costs down. It's a bit of a trial really as I'm fitting it on my garage roof where I do get a bit of shadow. I've paid the extra and gone for Optimisers, iBoost+ and Buddy so excess electricity can go to the Immersion heater. The 'Buddy' will tell the wife, who's at home most of the day, when we're exporting so she can go around the house turning all the lights on (oh, she does that already!).

I'll get to the point. I'm quite hands on but would like to get a look around someone else's system for various pointers and tricks so I don't look at it for the next 20 years thinking how differently I wished I'd installed it.

I'm Donegal Town based and would love to have a look at another install as locally as possible. Many thanks to all in anticipation.

Bren.

phester28 · 11-09-2019 7:01pm

Has anyone done any better. The best and only quote I got back from multiple attempts was 4.2k euro for 2.1Kw panels on an east west split on slate roof but still easy access.

1.2 on the east and 0.9 on west. That's as much as i can fit on the main roof.

4.2 before grant and BER is still too much IMO. The kit on solar city is around 2.2k inc vat (plus maybe 1-2 hundred for the dual string inverter). I have even tried roofers to see if they would install the bracketing but the two I tried said they have no clue.

air · 12-09-2019 3:56am

phester28 wrote: »

Has anyone done any better. The best and only quote I got back from multiple attempts was 4.2k euro for 2.1Kw panels on an east west split on slate roof but still easy access.

1.2 on the east and 0.9 on west. That's as much as i can fit on the main roof.

4.2 before grant and BER is still too much IMO. The kit on solar city is around 2.2k inc vat (plus maybe 1-2 hundred for the dual string inverter). I have even tried roofers to see if they would install the bracketing but the two I tried said they have no clue.

Would you have room for a ground mounted system anywhere perhaps?

Batfink69 · 12-09-2019 8:48am

phester28 wrote: »

Has anyone done any better. The best and only quote I got back from multiple attempts was 4.2k euro for 2.1Kw panels on an east west split on slate roof but still easy access.

1.2 on the east and 0.9 on west. That's as much as i can fit on the main roof.

4.2 before grant and BER is still too much IMO. The kit on solar city is around 2.2k inc vat (plus maybe 1-2 hundred for the dual string inverter). I have even tried roofers to see if they would install the bracketing but the two I tried said they have no clue.

So that's €2.8k after grant? If so, my back of fag packet/rule of thumb says if you use most of the electricity generated then your return could be about 8.5 years.

If I've assumed correct and all your costs are included in the €4.2k (installed and commissioned), then 8.5 years sounds better than most.

air · 12-09-2019 9:00am

Batfink69 wrote: »

So that's €2.8k after grant?

If I've assumed correct and all your costs are included in the €4.2k (installed and commissioned), then 8.5 years sounds better than most.

That's assuming 100% self consumption though which is very unlikely without a battery and a heavy average load.

Coltrane · 12-09-2019 9:25am

air wrote: »

That's assuming 100% self consumption though which is very unlikely without a battery and a heavy average load.

Agreed, the payback will be much longer as self-consumption falls, major factor probably being whether there's an electrical heating system.

But: let's remember that the scientists give us only 11 more years to avert a climate-disaster: https://www.theguardian.com/science/2018/oct/12/mary-robinson-climate-change-former-president-ireland-ipcc-report

If they're right, we'd be penny wise to scale back PV to try to hit faster payback periods/higher self-consumption!

I don't think we should focus too much on ROI calculations which disregard the costs of climate change.

air · 12-09-2019 9:35am

Coltrane wrote: »

I don't think we should focus too much on ROI calculations which disregard the costs of climate change.

I agree totally and my PV system generates about 3 times my consumption which helps to offset my other consumption.
Reducing consumption / energy efficiency is the best thing of all though. Almost infinite ROI from some measures too.

Coltrane · 12-09-2019 9:51am

air wrote: »

Reducing consumption / energy efficiency is the best thing of all though. Almost infinite ROI from some measures too.

Right, probably mainly because all renewables including PV have their own dirty footprint. If we buy it, it's transported, probably from China, by sea, having been fabricated with some dirty elements. As it obscelesces/stops working we want/are forced to dump it...probably well ahead of payback date according to an ROIDCC (see below) analysis for the geeks among us including me.

I reckon my best ROIDCCs (Returns on Investment disregarding Climate Change) were from LEDs, heating-control systems and insulation (especially: an insulated sub-floor to replace an old timber suspended floor!).

Worst was probably an A2W heat pump.

PV is somewhere in the middle at say 3-5% ROIDCC, taking me well beyond 2030 when scientists forecast these calcs may begin to matter much less...

The climate change plan for Ireland has a ranking of efficiency among renewables.

phester28 · 12-09-2019 10:22am

The ROR should be doubled if not multiplied by 2.5 to 3 as you will only be generating for a few hours per day (less than 12) Excess is given for free and even when the FIT comes in our best guess is a 4 to 1 cost. I.E you get 5C where as what you buy is 18 - 19C per KWH.

I average a 6kwh per day over the summer so pay back is not my driving factor as such

Over the long thread I have seen the most frugal "Unkle" who pulled in favors etc and got a cracking setup to people quoting their installs at decent prices but have not responded when messaged as to what company did the install.

garo · 12-09-2019 10:23am

Nice term. ROIDCC! I agree that LEDs are probably the cheapest, highest ROIDCC change you can make. I reckon I saved the guts of 1MWh in annual electricity consumption by changing all my downlighters to LED. I did the job myself so the cost to me was 25 LED bulbs, half of them dimmable, junction boxes and GU10 connectors so well under €100.
I got a proper factory insulated HW cylinder last year and heating controls this year. And of course PV.
But always good to remember that there is no cost to switching off lights when you leave a room and no charge to hanging up the washing on the line instead of using the dryer.

Coltrane · 12-09-2019 11:02am

garo wrote: »

Nice term. ROIDCC! I agree that LEDs are probably the cheapest, highest ROIDCC change you can make. I reckon I saved the guts of 1MWh in annual electricity consumption by changing all my downlighters to LED. I did the job myself so the cost to me was 25 LED bulbs, half of them dimmable, junction boxes and GU10 connectors so well under €100.
I got a proper factory insulated HW cylinder last year and heating controls this year. And of course PV.
But always good to remember that there is no cost to switching off lights when you leave a room and no charge to hanging up the washing on the line instead of using the dryer.

Absolutely. Or riding the bike to the shops instead of driving the EV, or keeping the EV until it croaks instead (and I'll struggle with this, I should just stop watching Fully Charged) of upgrading asap to a shiny new Model 3 or whatever.

Incidentally, my LEDs power off automatically when there's no motion (PIRs in each room, a Philips Hue system). The electrician told me it was the first house he had ever re-wired without light switches! It was a bit of a sell at home at the time, but we'd never go back now!

garo · 12-09-2019 12:40pm

Nice! I am probably too cheap to fork out for a Hue system just yet.

Yeah I still have an old petrol 03. I bike to work so it only sees use at the weekends. I plan to keep it until it croaks and then go straight to EV. I figure extracting more years out of that car is less damaging to the environment than getting a shiny new EV. Making a new car has its environmental impact and I am not a heavy user so the emissions saved don’t justify it.

Coltrane · 12-09-2019 1:04pm

garo wrote: »

I figure extracting more years out of that car is less damaging to the environment than getting a shiny new EV.

Yep, has to be right.

phester28 · 12-09-2019 1:59pm

Can we get this thread back to solar quotes please

Just got quote 2 back 4.4k for 2kwh 7 panels 4+3 east west split. thats 2.4k for about 3 days labour or 5 to 6 man days

reklamos · 12-09-2019 7:11pm

phester28 wrote: »

Can we get this thread back to solar quotes please

Just got quote 2 back 4.4k for 2kwh 7 panels 4+3 east west split. thats 2.4k for about 3 days labour or 5 to 6 man days

3 days to install, that does not sound right. Is there is something special about your roof?

Got 4.5kWh 12 panels, wiring, batteries, diverter done the same day.

phester28 · 12-09-2019 7:59pm

i was just speculating as to how much profit these guys are making. Nothing special about the install

garo · 13-09-2019 6:30am

phester28 wrote: »

Can we get this thread back to solar quotes please

Just got quote 2 back 4.4k for 2kwh 7 panels 4+3 east west split. thats 2.4k for about 3 days labour or 5 to 6 man days

I was quoted that amount by Electric Ireland. Is there a reason you are going for such a small system? Due to the current SEAI grant those small systems (and all other systems really) are a bit inflated in cost. Also what inverter do you get with that system? You can get a 4.2kW system with 4.8kWh battery for around 7k after grant. Less if you go for a smaller battery.

unkel · 13-09-2019 7:50am

garo wrote: »

Is there a reason you are going for such a small system? Due to the current SEAI grant those small systems (and all other systems really) are a bit inflated in cost. Also what inverter do you get with that system? You can get a 4.2kW system with 4.8kWh battery for around 7k after grant. Less if you go for a smaller battery.

+1

If you are going with the grant, go balls out and get a very good value big system with battery for €7k

If that's outside your budget, then don't go with an SEAI installer but get a local roofer / electrician and buy the parts yourself for a say €2-3k install

phester28 · 13-09-2019 8:26am

7 panels is all I can fit on my main roof in a built up area. no ground layout is possible. The roof has an unusual geometry that breaks up the flow of the roof with a valley.

I have rang around 4 roofers and none will install the brackets. One installer has been saying to not go SEAI and drill the slate. His point is that its approved for PV heating even by SEAI so its just Red tape for solor. I'm not sold on the idea

unkel · 13-09-2019 9:35am

Only cowboys will drill slates.

Batfink69 · 13-09-2019 10:51am

phester28 wrote: »

7 panels is all I can fit on my main roof in a built up area. no ground layout is possible. The roof has an unusual geometry that breaks up the flow of the roof with a valley.

I have rang around 4 roofers and none will install the brackets. One installer has been saying to not go SEAI and drill the slate. His point is that its approved for PV heating even by SEAI so its just Red tape for solor. I'm not sold on the idea

What part of the country are you in? I have a roofer coming next week who's been putting these things up for the last 3 years. We're South Donegal based.

He offered to fit the bars as well but I want to do as much as I can as that's just me.

phester28 · 13-09-2019 12:35pm

I'm down in sunny Cork, so perhaps too far

garo · 13-09-2019 2:53pm

Don’t go with anyone who promises to drill the slate. Keep looking. I am sure you will find someone to do the install for cheaper. A non-grant install of 7 panels shouldn’t be more than 3k tbh assuming you are going for a non-hybrid inverter. Also where are you putting the inverter and are the cable runs from panels to inverter and then inverter to fuse box straightforward?

phester28 · 13-09-2019 5:16pm

yup all straight forward. inverter in the attic so no need for a fireman disconnect (i think). Panels to inverter I assume go through a penetration into the attic or else drop to the eves and then into the attic. Panels are on the main roof

garo · 13-09-2019 6:56pm

Use a roof vent or as another forum suggested:
Under a tile and through an over lap in the felt. Nibble a groove to the underside of the tile just enough for the DC cables and sticky Lead flashing over cable entry point. Koppex the DC cables within the loft. Make sure to label the DC cables accordingly. Koppex is not a reg or rule just looks good.

jimmyging · 14-09-2019 7:08am

My most recent quote
6kw array ground mounted
5 kw hybrid inverter
6.4 kw battery
Eddi
11k including grant

AidenL · 14-09-2019 9:33am

I still haven't pulled the trigger. Looking for some opinions, even though its probably the wrong time of the year to install PV now.

Most recent electricity bill, 19th July till 11th December, 67 days.

Used 807 day units, 12 per day, 339 night units,5 per night. Total cost of the electric, after discount, including VAT, but excluding standing charges and PSO was 170 euros. So that's the amount to play for.

So, I guess my base load and night load would be right for PV and a 5kw battery which would probably take me through the night, at least at this time of year.

Any thoughts?

Tradnuts · 14-09-2019 11:29am

Hi guys,
I'm waiting for a few quotes back for PV for my roof.
System i'm quoting for is a 2KW system with a diverter for the immersion.
Fairly straight forward setup on an easy roof layout.
I will qualify for the grant as the house is built before 2011.

Any idea's what price i should consider as competitive?
Thanks in advance

bunderoon · 14-09-2019 12:13pm

Tradnuts wrote: »

Hi guys,
I'm waiting for a few quotes back for PV for my roof.
System i'm quoting for is a 2KW system with a diverter for the immersion.
Fairly straight forward setup on an easy roof layout.
I will qualify for the grant as the house is built before 2011.

Any idea's what price i should consider as competitive?
Thanks in advance

May I ask - what type and size of hot water cylinder you have? Copper / Steel 200Ltr / 250Ltr etc? And where is the immersion situation in the tank? Top/middle/bottom.

Can someone answer the question of if the immersion is half way in the tank, will the water below the immersion ever heat to a sufficient temp, say >50c ?

Tradnuts · 14-09-2019 12:36pm

bunderoon wrote: »

May I ask - what type and size of hot water cylinder you have? Copper / Steel 200Ltr / 250Ltr etc? And where is the immersion situation in the tank? Top/middle/bottom.

Can someone answer the question of if the immersion is half way in the tank, will the water below the immersion ever heat to a sufficient temp, say >50c ?

Hi, Thanks for the reply.
My cylinder is 300ltr Joule Triple coil, very modern, fully insulated.
The immersion is in the middle.
Thanks again!

bunderoon · 14-09-2019 2:13pm

Tradnuts wrote: »

Hi, Thanks for the reply.
My cylinder is 300ltr Joule Triple coil, very modern, fully insulated.
The immersion is in the middle.
Thanks again!

: ) that's exactly what I have too.
Still pondering whether tubes or pv with diverter is best way to go. No one hone during the day so pv would heat the water (well half of it) all year around I would think. But am concerned about the bottom of the tank due to the possibility of legionnaires.... I bought two cheap hot water sensors and don't see the bottom of the tank heat very well when the immersion is on for hours. Above the immersion element, the tank gets to 60c and sometimes higher.

bunderoon · 14-09-2019 2:14pm

And since the solar tube coil is at the bottom of the cylinder, the whole tank will heat if I get 30 tubes..

Tradnuts · 14-09-2019 3:32pm

bunderoon wrote: »

: ) that's exactly what I have too.
Still pondering whether tubes or pv with diverter is best way to go. No one hone during the day so pv would heat the water (well half of it) all year around I would think. But am concerned about the bottom of the tank due to the possibility of legionnaires.... I bought two cheap hot water sensors and don't see the bottom of the tank heat very well when the immersion is on for hours. Above the immersion element, the tank gets to 60c and sometimes higher.

Yes, the same setup as me so!
I was thinking of the PV's because i didn't want the expense of the servicing of the tube liquid every 18-24 months and cost of the pump replacement at some stage in the future. (plus the running costs).
At least with the PV's i get some reduction in electricity bill and a fair amount of hot water, especially in the summer when the oil heating is not on and we are only using the immersion. I would imagine i would need the immersion very little for the 4 months of the summer with PV's.

Whats the likelihood of legionnaires?
Where did you get the hot water sensors?
Thanks

bunderoon · 14-09-2019 6:08pm

Tradnuts wrote: »

Yes, the same setup as me so!
I was thinking of the PV's because i didn't want the expense of the servicing of the tube liquid every 18-24 months and cost of the pump replacement at some stage in the future. (plus the running costs).
At least with the PV's i get some reduction in electricity bill and a fair amount of hot water, especially in the summer when the oil heating is not on and we are only using the immersion. I would imagine i would need the immersion very little for the 4 months of the summer with PV's.

Whats the likelihood of legionnaires?
Where did you get the hot water sensors?
Thanks

Im in the same mind as yourself more or less.

There is talk on here before about Thermomax Tubes that dont need a dump or have the glycol replaced as often as 24 months, more like 3-4 years depending on how hot the summers were preceding them.

For us, we dont use that much electricity. No one in the house all day and efficient appliances so the main cost we'd have is hot water.
The cost of PV would be about double that of the tubes for equivalent hot water generation. And to make use of PV in the evenings means a decent battery and thats 1000s more. Payback would be 15-20 years for us I think.

But with FIT and the cost going down, it is still temping to start small and see from there.

Don't know too much about the legionaries, just know that they can take hold at the bottom of the tank as the water is cooler and possibly stagnant.
Copper cylinders prevents it naturally. Stainless steel doesn't.

The sensors are just cheap Aliexpress ones
I taped them up a little to make sure that the ends done come off and used a wire from a coat hanger to slide the end in to the sensor cavity in the cylinder.
Works perfect for what I want for the moment. I will get proper ones one I know which way I am going to go.

phester28 · 14-09-2019 6:25pm

Tradnuts wrote: »

Hi guys,
I'm waiting for a few quotes back for PV for my roof.
System i'm quoting for is a 2KW system with a diverter for the immersion.
Fairly straight forward setup on an easy roof layout.
I will qualify for the grant as the house is built before 2011.

Any idea's what price i should consider as competitive?
Thanks in advance

The quotes im getting in an east west split of 2kw are around 4.2k before grant. That is on slate.

about 150 cheaper for your inverter and a little less on the wiring so my guess is 3.8-3.9k would be about right before grant.

Keep us posted with your quotes

unkel · 14-09-2019 8:56pm

Tradnuts wrote: »

System i'm quoting for is a 2KW system with a diverter for the immersion.

Don't get an immersion diverter for such a small PV system. It will never pay for itself. Cheaper to just let the overproduction go back to the grid for free (it's also likely we'll get a FIT some time in the near future)

garo · 16-09-2019 10:22am

Agree with Unkel. With a 2kW system you will only get a full tank of hot water 3 months of the year on sunny days only. For ~7k you can get a 4kW system with a small battery. I have had my system for only a month and it is amazing how well even a small battery covers things like a cloud covering the sun when the oven is on.

Alkers · 16-09-2019 11:13am

AidenL wrote: »

I still haven't pulled the trigger. Looking for some opinions, even though its probably the wrong time of the year to install PV now.

Most recent electricity bill, 19th July till 11th December, 67 days.

Used 807 day units, 12 per day, 339 night units,5 per night. Total cost of the electric, after discount, including VAT, but excluding standing charges and PSO was 170 euros. So that's the amount to play for.

So, I guess my base load and night load would be right for PV and a 5kw battery which would probably take me through the night, at least at this time of year.

Any thoughts?

I would think a 5kWh battery wouldn't make economic sense for you. You should get a smaller battery just to tide you over until night rate kicks in. In almost all instances, using a battery instead of night rate electricity doesn't make any sense financially.

What is the cost of the 5kWh battery? Divide this by your night rate unit cost and then work out how many battery cycles are needed before it pays for itself.

garo · 16-09-2019 5:58pm

AidenL, I agree with Alkers here. A 4.8kW Pylontech battery setup is about €2000-2400. I have a very similar usage profile to yours and was consuming about 15 units a day in the summer. Mind you in the winter you would be consuming 18-20 due to longer nights and more use of the clothes dryer. I went for a 4.8kW system and in the summer it definitely produces more than I can use. But on the flip side I get more production in the evenings and on cloudy days. I have an EW orientation.
Battery costs are coming down at ~10% per year and if we get a Fit it will render the additional battery useless. According to my calculations it costs anything from 6-10 cents to cycle one KWh through a battery. So you don’t save a huge amount over night rate electricity.

AidenL · 16-09-2019 6:06pm

Alkers wrote: »

I would think a 5kWh battery wouldn't make economic sense for you. You should get a smaller battery just to tide you over until night rate kicks in. In almost all instances, using a battery instead of night rate electricity doesn't make any sense financially.

What is the cost of the 5kWh battery? Divide this by your night rate unit cost and then work out how many battery cycles are needed before it pays for itself.

garo wrote: »

AidenL, I agree with Alkers here. A 4.8kW Pylontech battery setup is about €2000-2400. I have a very similar usage profile to yours and was consuming about 15 units a day in the summer. Mind you in the winter you would be consuming 18-20 due to longer nights and more use of the clothes dryer. I went for a 4.8kW system and in the summer it definitely produces more than I can use. But on the flip side I get more production in the evenings and on cloudy days. I have an EW orientation.
Battery costs are coming down at ~10% per year and if we get a Fit it will render the additional battery useless. According to my calculations it costs anything from 6-10 cents to cycle one KWh through a battery. So you don’t save a huge amount over night rate electricity.

The battery seems to be around 3000 including VAT, less the grant? Hard to see exactly how much it is in the quote, I got a lump sum price. So that would be 2k nett, divided by 0.08 - so 25,000 cycles? Is that correct?

Or am I doing the calls wrong?

Would the battery not cover say, from 8pm these days till midnight, with a saving on day rate if it was fully charged on a bright sunny day like this? And then night rate overnight at 8 cents? And back to recharging the battery tomorrow?

What am I missing? Im not sure what the saving would be on a smaller battery.

And in winter, is it not sensible to charge the battery overnight at night rate and expend it during the dull winter mornings?

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