Is it worth our while?

unkel

@cnocbui - "this site says 2kw of panels will cost €5,500"

LOL I put up 4.5kwp on my shed DIY for about €2k spring of last year. At the time I calculated the pay back period with my usage at about 2.5 years, but before any of these electricity price increases. Now the pay back period is more like 1.6-1.8 years. In other words, it will have almost fully paid for itself in electricity savings by now. And I could take the whole system down tomorrow and sell for more than I paid. Have your cake and eat it. All tax free too.

BTW where do you get that 5.29% guaranteed return on a zero risk investment after taxes?

cnocbui

https://www.boards.ie/discussion/comment/119619594#Comment_119619594

Your DIY tales and costings don't count.

BHP shares.

jkforde

woah, who are offering the 5.29% interest rate? genuinely interested

https://www.moneyguideireland.com/best-savings-rates/fixed-term-deposits-more-than-1-year

unkel

https://www.boards.ie/discussion/comment/119619639#Comment_119619639

Why don't they count? Because @cnocbui says it only counts if you get an overpaid installer to do it, who overcharges you for parts and labour and makes a huge profit? 😁

BHP shares? LOL, hardly risk free, not a guaranteed return and any gain is taxable for CGT.

unkel

https://www.boards.ie/discussion/comment/119619641#Comment_119619641

Don't forget Irish price bonds. They also pay about 0.5-1% and tax free too. But it's luck of the draw, I have some and I think I have averaged about 0.2% return 😂 (or basically a loss of several percent of my capital in real terms because of inflation)

cnocbui

https://www.boards.ie/discussion/comment/119619641#Comment_119619641

BHP shares currently have a dividend yield of 12.42%. $1,000 invested 20 years ago would now be worth $5,719.30.

Ubbquittious

I think that ESB calculator hasn't been updated since they brought in all those price increases.

graememk

https://www.boards.ie/discussion/comment/119619902#Comment_119619902

Shares.. is where you went. Generally the most risky investment going.

Sure you could 5x your money.. or pick the wrong one and have 0.

If we take our guide on the quotes thread of 1.2k/kWp a 2kwp system should be circa 2.5k,

1600kwh generated self use would be high because it's a small array, say 75%

291 isn't actually too far off ... But the cost of putting them up is.

Instead of just going nah, have a look into it other than a cursory glance. (Since when would any energy supplier be a good deal for anything other than actual energy when it's all sub contracted out anyway!)

jkforde

https://www.boards.ie/discussion/comment/119619902#Comment_119619902

....

Alkers

https://www.boards.ie/discussion/2058262744/is-it-worth-our-while

Do either of you work from home?

Bungalow should be a cheaper & more straightforward install.

The thing around here tends to be to whack up 10k of panels to generate as much as possible but I think a 2.5-3kW system is the sweet spot in terms of using a high percentage of what you generate, not ending up with loads of excess going to grid and most importantly getting the install for as cheap as possible. You should be paying less than 4k after grant for a smallish system.

unkel

Not sure if you are right there @Alkers - it's a simple calculation though when planning an install, get quotes for different size systems. Say a kwp extra costs €800 installed. This makes 800kWh per year south facing in a good area of Ireland. That makes well over €100 tax free return per year in FIT if you don't use any of it yourself, worst case scenario. That's an extremely high return on a low risk investment

In Germany many people chose to have PV installed solely to feed in to the grid (they get a higher FIT when doing that), purely as an investment

Alkers

https://www.boards.ie/discussion/comment/119620203#Comment_119620203

Not every extra kWp will earn €100 in fit though, particularly if you are already coming close to the €200 tax free allowance on fit

unkel

@Alkers - You mention 2.5-3kwp as the sweet spot, you can add a few more kwp before you hit the tax free threshold. And the sums are quite simple really. To dismiss it even just from an investment point of view without doing these sums is unwise.

bullit_dodger

Yeah, I'm sort of with unkel there - although technically your right Alkers. If you have a smaller system, it's true you will have a higher self-consumption rate. Logically if I install 1x 400watt panel and my base load is higher than that, I'lll be at 100% self-consumption. Leave aside the FIT side of things for a minute, getting a high self-consumption rate is good as it does mean in theory I'd have the shortest payback period.

The problem where that logic breaks down is in the fact that 1x 400 watt panel is worth feck all to me. So naturally we need more than that. 1x 400 watt panel in the middle of summer might do 400 watts, but in the middle of Sept it ain't going to produce that. So we typically size for Sept/Oct and Feb/Mar. Where it gets interesting is that a string inverter will cost the same if I have 1 panel or 12 panels, so the embedded "inverter cost per panel" is cheaper with 12 than 1. This is (partly) why also why over on the quotes thread the bigger systems tend to be better "value" compared to the formula - that and the fact that it costs the same to get 2 guys on your roof for 1 panel verses 12 panels. (I won't go into micro-inverters here)

So what's the sweet spot then? Ironically I don't think there is one, or at least I think every house is different due to roof orientation, consumption profile (when in the day), annual consumption (how much per year), EV usage (eg. needing 1.5Kw minimum generation for some cars) , battery installation. You need to size the installation to the needs.

That said, I think 3Kwp is a good well balanced system. I think most people installing one will do very well with it.

Aside: Not seeing why hitting the tax free threshold is bad. Yeah, nobody wants to pay tax, but if I'm earning money from panels (after paying tax) why is that a bad thing? I certainly wouldn't size a system to stop me from reaching that threashold. It wouldn't even enter my thinking

@Girl Geraldine

https://www.boards.ie/discussion/comment/119611213#Comment_119611213

https://www.boards.ie/discussion/comment/119611700#Comment_119611700

To put this in perspective: I have the kind of skills that are liable to get me somewhere between slightly and terribly injured, so anything that involves picking up tools is a no-no for me. I'm not joking - I have some useful skills alright, but they do not involve electricity, gas, water or sharp implements.

I've a good head for research, but I need to allocate time to it sparingly.

The reason I'm asking here is precisely because it is an echo chamber. The upside of that is that there are people posting here with real-life experience, and that has to be useful to us. On the other hand, it does mean running into the "enthusiasts" point that @Girl Geraldine references. If this kind of work is something you're enthusiastic about, then all the researching, analysing, finessing and tinkering about is a delight, whereas for me it's an absolute pain in the arse. In clichéd terms, I'm looking for point-and-click, or plug and play. And being honest, regardless of my environmental concerns, if the choice is between spending wads of money now and getting it back over 20 years, or spending more or less the same wads of money spread out over 20 years, then maybe the hassle of installation isn't worth it.

But I'd still tempted. I think we have a setting that's as good as you'll get. East coast, and an almost due south facing big roof with nothing blocking the light. On the other hand, there's not a chance we'd be doing any of this ourselves, so it'd be a case of quotes for paid installation all the way - which would make initial costs higher and the payback period longer. I think there's still a bit of thinking to be done.

Thanks for all the comments (so far, as I'm still reading the thread).

Bobeagleburger

Don't overspend with the thoughts of earning it back with FIT.

Get plenty of quotes. You should be able to get a 6kW system, 7.2kW battery and Eddi for 11-12k post grant. Not brilliant, but compared to some of the quotes I've seen it's ok.

Careful of posters disguised as installers, especially on that Facebook page. Less likely here but it happens.

Good luck.

Remember these ball part post grant calculations. If it's near this you're good. Otherwise run away.

1.2k per 1kW panels

1250 per 2.4kW battery

500 Eddi

unkel

It most likely will pay back quicker if you go for the largest possible system in terms of PV panels, but with NO diversion of any kind. No hot water immersion diverter, no diversion to an electric car and certainly no battery. Get quotes for a plain 6kwp system and let the generous FIT (feed in tariff) system do its work...

More Music

https://www.boards.ie/discussion/comment/119616655#Comment_119616655

12,000kWh per year - holy sh1t. So what would your PV panels reduce your ESB mains electric consumption to p/a? Or what would you be happy with?

I used 4048kWh for the whole of 2021. I'm at 2744kWh so far in 2022. That's with no panels or any supplemental generation.

This is what pisses me off. You can conserve and insulate etc. to reduce your costs (or even install panels) and they just jack up the price anyway.

I cannot reduce anymore, or we will be living in the dark.

I'm at a level I'm happy with. Maybe I should install PV and export most of it back to the grid!!

loopymum

I'm almost afraid to post here how much we use per year in kw

I might start a survey.

We are electric only

No gas or oil of any description

2 electric cars albeit one is very lightly used

unkel

Don't feel bad, @loopymum. Here's why your usage probably isn't all that high, these are rough figures but you get the picture:

An average Irish home uses 3MWh in electricity per year if heated with gas / oil and if there are no EVs plus about 1500m3 of gas (equivalent is 16MWh in electricity) plus 18000km in diesel which is about 1000l (equivalent is 10MWh in electricity). Total 39MWh

If that household does electric only has the same basic 3MWh, and modern electric heating with a heat pump uses about half above, so say 8MWh an EV that does 18k km per year at 18kWh / 100km uses about 4MWh per year after charging losses . Total 15MWh, so less than half of above in reality and much cleaner and greener as more and more of this is coming from renewables, while oil / gas / petrol / diesel are almost zero percent renewable and do have tonnes of emissions!

graememk

https://www.boards.ie/discussion/comment/119644345#Comment_119644345

Thats something that seems to be overlooked quite a lot when heatpumps are involved.. there's no gas bill.

@unkel

https://www.boards.ie/discussion/comment/119640062#Comment_119640062

https://www.boards.ie/discussion/comment/119640394#Comment_119640394

Differing views in those posts.

We don't have a hot water tank or an EV, so what @unkel says might be more relevant to us. How big (in roof area) would a 6 kW system be?

A battery would help us time-shift, and presumably save money on bills. But it adds cost to the installation, whereas FIT doesn't (does it?). But without a battery, and with relatively little consumption during the weekdays, is it not the case that most of the time we'd be generating electricity and sending it straight to the grid?

slave1

https://www.boards.ie/discussion/comment/119644248#Comment_119644248

When I was on a longish commute pre COVID we were 20 MWh a year, is what it is

unkel

@[Deleted User] - 6kwp is roughly 16 panels of the most typical size sold these days which is about 1.76m*1.04m and about 375W

Unless you do a lot of cycling the battery, build your own and buy the cells cheaper than they are available for in the market right now, with the current generous FIT a battery simply won't pay for itself. Now of course, the FIT could go down, the day rates could go further up, the battery parts might hold their value really well, etc. plenty of variables in there

That's coming from me BTW, I have tonnes of renewables, both a large solar thermal system and a huge solar PV system and a 20kWh battery and a Zappi to divert excess electricity to the car when the battery is full. I am on the cheapest night rate available in Ireland as per renewal a few weeks ago (7.9kWh) and I do a lot of peak shifting so I barely use any day rate electricity

ELM327

https://www.boards.ie/discussion/comment/119644068#Comment_119644068

My panels are only in a couple of weeks so I'm as yet unsure what they will reduce it to.

I'll be happy when I'm off grid!

In terms of money spent vs money saved, the best way however would be a small array to cover the base load of the house in summer. Paid back in 12-18 months

DC999

@unkel, yeah, I convinced myself we were amazing with a house using only 2.8MWh a year. But then we had no EV. And cook on gas and heat on gas. So electricity was only one of our 3 energy bills (as patrol is basically an energy bill). Now with the EV we’ve only 2 energy bills (petrol is gone), and I can use electric rads (a little from solar) to supplement the gas heating outside the full on winter (so can reduce gas a little).

Our EV uses the same amount of juice as our house now pretty much. Which is still a surprise. I did the maths when buying it, so was aware. But to think your mode of transport (which for us is low mileage) uses as much as a whole house….Shows how wasteful cars are. Not suggesting I flog mine, but are heavy to run.

Will move off gas cooking in the future for sure. And always planned too. Less gas we use, the better. 

DC999

https://www.boards.ie/discussion/comment/119644068#Comment_119644068

Get PV anyway and it will reduce your bills big time. As others said here, I waited and should have gotten it sooner. Only live 2 months but will never live in a gaff without it again. We're all gonna use more electricity in the future (EVs, more from gas cooking and heating, more tech in houses...).

Energy costs are only going one way and not just for a year or 2, imho. Solar gives you control back from those. Look at solar as a service if shelling out in one go isn't a runner. It's the same result. Enjoy the hunt!

waterwelly

https://www.boards.ie/discussion/comment/119645248#Comment_119645248

People need to be wary about energy costs only going one way, obviously there was a major shock to the system (Ukraine) which resulted in gas shortages, high oil prices and a run on coal as everybody paniced.

I believe this will ease and energy prices will fall slowly over the next few years, maybe not to where they were but it will fall.

Even if the Eur improves against the dollar, which it always does at some point, oil and gas will be cheaper.

Now I am still going all in on PV at some point but I am cautious about paying top dollar right now.

maxpet

https://www.boards.ie/discussion/comment/119618691#Comment_119618691

Do you charge a battery with this setup ?????

Ubbquittious

https://www.boards.ie/discussion/comment/119646111#Comment_119646111

No not yet. I am working on it though, going to make a charge controller and have a change-over so I can send the power from the panels to either the grid tie inverter or charge controller

tom1ie

Hi all, so what sort of price would you be looking at for supply and installation of a typical 6kwp array which as per previous post I understand to be approx 16 panels?

This would be no battery as any excess I’d be looking to go to FIT.

Dublin area.

Also is there a limit to the size of array you can have or the max amount of panels? Do you need planning permission once you go over a certain amount?

https://www.boards.ie/discussion/comment/119644917#Comment_119644917

I'd guess that 16 panels is about half of my south-facing roof.

https://www.boards.ie/discussion/comment/119645229#Comment_119645229

See, if I was able to use a bit of solar electricity to power electric rads and cut the gas heating that would be a real bonus. But of course I'd be generating less leccy at just the time of year I'd need the heating. Ah well.

yankinlk

https://www.boards.ie/discussion/comment/119652321#Comment_119652321

The formula is in the FAQ sticky... so 6Kw x 1.2Keuro = 7200euro after grant. Check this against the quotes thread and get 3 quotes minimum

Good luck

tom1ie

https://www.boards.ie/discussion/comment/119653382#Comment_119653382

Many thanks and I should’ve read that sticky first before posting- very informative.

unkel

https://www.boards.ie/discussion/comment/119653333#Comment_119653333

Well, you would be surprised. The colder it is, the better PV works. Today started a lot colder than it has been recently but as soon as the sun was out, my car was being charged with the max 7.4kW the charge point can provide. Purely from the sun. While I also have some small electric radiators running in the house

unkel

Taken just now. Anytime the sun is out, even in autumn or spring around the midday hours and car is charging at max rate from the sun:

ELM327

Today was the first day I saw over 7kW being generated too

unkel

Nice one, welcome to the club! My mate here in the same cul-de-sac has an even slightly bigger setup than me. If the sun is out in full, between the two of us we power the baseload of the entire estate (about 80 houses)

slave1

Due (I assume to high voltage) I get 7.6kW max into to car

graememk

https://www.boards.ie/discussion/comment/119662020#Comment_119662020

7600/32 is only 237V So not that high a voltage, although decent when pulling 32 amps!

unkel

Love that picture @slave1 😎

So you have set the zappi to have priority over the eddi? How did you do that?

slave1

https://www.boards.ie/discussion/comment/119662602#Comment_119662602

on the App, hold the Zappi (or EDDI) Icon for a second, then the app will move to another screen and allows you to "drag" either EDDI or Zappi to first priority

bullit_dodger

https://www.boards.ie/discussion/comment/119654954#Comment_119654954

My mate here in the same cul-de-sac has an even slightly bigger setup than me.

Get da f... :-)

Padre_Pio

I'm buying a new build, fully electric, no gas or fireplace. I have a fairly large roof, directly south facing with no trees or shadows.

It seems solar is the way forward, but I don't know if it's worth waiting a year to figure out my use. Would anyone have any average use ballpark figures for two people, working from home in a new a rated house, no EV(yet)?

DC999

https://www.boards.ie/discussion/comment/119665336#Comment_119665336

Hey, no need to wait to see your usage I’d suggest. You can get close enough to that for now.

It's gonna be the exact same usage you have now. Bar add on electric heating if you don't have that now. Your heating should cost less but all other devices will use the same power. And add electric cooking if don’t have now. So that’s the bits you’re looking for. I’ve neither a warm house nor electric heating or cooking so others can answer that.

Call your electricity provider and tell then you’re looking at your usage and want to see how much you use per year. Or check your bills.

If new to it, WFT is around a constant 100W per device give or take for just the laptop + screen. But gaff needs to be warmer than before usually (but you're likely sorted there on a new build with good insulation).

New builds likely have some solar panels as boosts their BER. So ask about that and get the details of the system, not just that it's 'X panels'. But they tend to put on the bar min. to hit the BER afaik.

And start to track your usage a little more detailed from now. How much per day, per week, per month… Then you’re better armed for the best tariff for you (pre solar) plus for what ye would use on solar. If this is your forever home, get solar asap. Even try the solar as a service from 40 p/m – you’ll be stretched with new house costs of course so that could work.

EV wise we’ll use a little under 3000kWh a year for our Leaf. Only does 15k per year. That’s back of envelope stuff. So can use that as a crude multiplier for your annual usage. Factor in that for the poorer months for solar output you’d be charging an EV on a D/N meter. Excess from solar (of which there is plenty if car is at home during the day) is a bonus. 

https://www.boards.ie/discussion/comment/119654783#Comment_119654783

Interesting, and indeed surprising. I wonder how much you'd generate in the coldest months of the year, though.

Seems to me my choice should be between (1) using a battery to store what's generated in the day and push that into some small electric radiators (morning or evening) to reduce the load on my GFCH, or (2) no battery and using FIT to offset some of the cost of buying power from the network (presumably more excess in summer than winter). I need to do some sums, but it still looks like FIT makes more sense than incurring the extra cost of a battery.

https://www.boards.ie/discussion/comment/119663003#Comment_119663003

It's not the size of your setup that counts, it's what you do with it. 😁

unkel

https://www.boards.ie/discussion/comment/119674310#Comment_119674310

Yep, the FIT is so generous that it makes more sense to send any surplus to the grid and not get a battery (unless you DIY and get the parts at relatively good prices - even then it doesn't make a lot of sense)*

You still generate quite a bit in the coldest months of the year. But there will be dark wet days with very little day light that you will generate only a 0.3-0.5kWh with a medium size system, so not a lot, in fact almost nothing on such a bad day. But you will also have very sunny days with temps around or even below zero that you will produce tonnes of PV and even very hot water from solar PV tubes!

*my own system is a bit of an outlier in that I have so much PV that if I exported all that I produced, I'd pay significant income tax on a lot of it, which would defeat the purpose for me and make it cheaper to store night rate and use it for heating during the day with my 20kWh battery (which I might further increase). Also I don't have a smart meter yet, and might not have one for years, so I don't get paid for my actual export. You see how the government is making a mistake here with that income tax policy and the CRU is making a mistake with their smart meter policy?

bullit_dodger

https://www.boards.ie/discussion/comment/119674311#Comment_119674311

There's a bit of a background story there that unkel would give Moneypoint a run for it. The fact that there is another person in his estate with even more PV totally shocks me......in a good way.

I'm on 7.6Kwp and hoping to expand to 8.8Kwp at which stage I'll be "done" at least for the next couple of years. It's great to see PV being aggressively adopted by a few nutcases. Even had someone ring my door last week, complete randomer looking for "how the panels working out?"

unkel

@bullit_dodger - I bullied him into it and he is very much of the "go big or go home" school of thought. Got it all in by the start of summer (all DIY) just before the real price hikes and material shortages and price hikes started, so he is delighted with it 😁 Further bullying him into getting one or more EVs now 😂