Solar PV - is it worth it?

eire1987

unkel wrote: »

Looks like you fell for their sharp sales tactics. But don't take my word for it. Do yourself a favour and pay an independent consultant go over the "hone system" plans before you commit your money.

Ok, so you have used their service before?

bleary

unkel wrote: »

The inventor behind the Hone system is soon to become a billionaire

Linky

Published over 2 years ago. Wonder if those other companies have caught up yet. "I have it on good authority that some other companies have spent €250m trying to get to where we are, but they're nowhere near"
No sign of the factories designed specifically to create more jobs

"He emphasises plans to set up factories wherever its technology is rolled out, each employing about 700 people, with a manufacturing process intentionally designed not to rely on robots or automation, in order to create the maximum number of jobs."
Anyway off topic

wexfordman2

bleary wrote: »

Published over 2 years ago. Wonder if those other companies have caught up yet. "I have it on good authority that some other companies have spent €250m trying to get to where we are, but they're nowhere near"
No sign of the factories designed specifically to create more jobs

"He emphasises plans to set up factories wherever its technology is rolled out, each employing about 700 people, with a manufacturing process intentionally designed not to rely on robots or automation, in order to create the maximum number of jobs."
Anyway off topic

I sometimes wonder his any reputable "journalist" and "newspaper" can publish articles like that without even basic challenges like that.

Does anyone know where any of these factories employing 700 people are ?

denismc

eire1987 wrote: »

Ok, so you have used their service before?

If you do go ahead with this system could maybe report back here and let us know how you find it.

eire1987

denismc wrote: »

If you do go ahead with this system could maybe report back here and let us know how you find it.

Yeah no problems. Like tbf I don't dispute much of debate surrounding them in terms are talking BS or not because I can't speak about solar panels... However I must say that I have got an outside opinion about them (the guy i was talking to would know a bit about solar panels) he did say that some of that RTE report was a bit bogus in terms of the house they used, does the system acutally work etc... But he did make a point to me that im doing a new build rather than doing a retrofit.. also the company were using for the timber frame have their own system.. so it is a different situation...

However once the quote is in and we finish our plan with the company thats building it I will report here when we start at it

ActingDanClark

Currently in the process of getting quotes. South facing roof which will take max 7 panels, allowing 2240 KW. Price including Eddi and nett of grant approximately €3100. I'm not hugely hung up on ROI, won't be borrowing $$ but just seeking opinions whether it's worth doing?
(Always someone at home daytime, consume 4195 units pa, electric shower which I'd happily replace)

unkel

I wouldn't buy an Eddi with a small setup like that. It's cheaper (and greener) to give your excess production back to the grid for free.

ActingDanClark

unkel wrote: »

I wouldn't buy an Eddi with a small setup like that. It's cheaper (and greener) to give your excess production back to the grid for free.

Neglected to mention house is located north east Wicklow. Would you envisage this system making much of a dent in my electricity bills? All led bulbs, all appliances at least A+

unkel

There's always someone in your house during the day, so they can switch on the dishwasher, washing machine, dryer, do the hoovering, cut the grass with an electric mower, etc. when it is bright / sunny. One of the above at a time. And yes it will make a significant dent in your electricity bills if you adjust your behaviour towards making the most of your solar PV

Payback times are exaggerated by almost everybody almost all of the time though. Your case is good, you get the subsidy, if you get a decent price for your install you are probably talking about 10-15 years or thereabouts. But of course it is not just about money

uck51js9zml2yt

ActingDanClark wrote: »

Currently in the process of getting quotes. South facing roof which will take max 7 panels, allowing 2240 KW. Price including Eddi and nett of grant approximately €3100. I'm not hugely hung up on ROI, won't be borrowing $$ but just seeking opinions whether it's worth doing?
(Always someone at home daytime, consume 4195 units pa, electric shower which I'd happily replace)

Why not get a battery for the evening ?

ActingDanClark

Ayleen Polite Mockingbird wrote: »

Why not get a battery for the evening ?

Installer says it's not worth my while?

ActingDanClark

unkel wrote: »

There's always someone in your house during the day, so they can switch on the dishwasher, washing machine, dryer, do the hoovering, cut the grass with an electric mower, etc. when it is bright / sunny. One of the above at a time. And yes it will make a significant dent in your electricity bills if you adjust your behaviour towards making the most of your solar PV

Payback times are exaggerated by almost everybody almost all of the time though. Your case is good, you get the subsidy, if you get a decent price for your install you are probably talking about 10-15 years or thereabouts. But of course it is not just about money

Average electricity bill is e160 so it'd be nice to see that reduced.

wexfordman2

ActingDanClark wrote: »

Average electricity bill is e160 so it'd be nice to see that reduced.

Is that per month or bi monthly ?

denismc

ActingDanClark wrote: »

Currently in the process of getting quotes. South facing roof which will take max 7 panels, allowing 2240 KW. Price including Eddi and nett of grant approximately €3100. I'm not hugely hung up on ROI, won't be borrowing $$ but just seeking opinions whether it's worth doing?
(Always someone at home daytime, consume 4195 units pa, electric shower which I'd happily replace)

Thats a decent price, I paid similar for a similar sized system before the grant. That EDDI unit unit alone costs over £500 sterling before installation, so its not going to pay for itself anytime soon but it is a nice to have.

If you have someone at home during the day cooking, washing, cleaning then you will definitely see a reduction in your bills.
My system is 2.1kw and I reckon I use between 1/3 and 1/2 of what I produce.

uck51js9zml2yt

Just reading about the Eddi. Looks a interesting idea.

Can I ask a question? The solar panels generate electricity for use. Then divert to the immersion heater until it reaches max.
Is it possible to then divert the balance to a battery rather than back to the grid for nighttime use?

ActingDanClark

wexfordman2 wrote: »

Is that per month or bi monthly ?

Bimonthly

unkel

Ayleen Polite Mockingbird wrote: »

Can I ask a question? The solar panels generate electricity for use. Then divert to the immersion heater until it reaches max.
Is it possible to then divert the balance to a battery rather than back to the grid for nighttime use?

Yes that's all possible, but with a small PV array (say less than 3-4kwp), it is cheaper to give away your electricity for free to the grid than to use a diverter (Eddi) and much cheaper than using a battery

funnyname

unkel wrote: »

Yes that's all possible, but with a small PV array (say less than 3-4kwp), it is cheaper to give away your electricity for free to the grid than to use a diverter (Eddi) and much cheaper than using a battery

Can you explain the maths of that?

KCross

funnyname wrote: »

Can you explain the maths of that?

The Eddi is €400. Maybe add another €100 to fit.

A 2.4kWh battery plus hybrid inverter costs about €2k and €300 for labour. A net €1300+ to you after grant.

So, net cost to you for both diverter systems will be about €1800+


€1800 of night rate electricity would equate to 22,000 units of electricity. You will "never" see your money back for either of those systems to save you 22000 units of electricity... hence "cheaper" to just give the excess away to the grid and save yourself the €1800 for something else.

unkel

And before anyone else butts in - yes you can use the battery in the evening time for your peak electric consumption (before night rate kicks in) and yes in some battery systems you can load them up with night rate and use the cheap night rate for your expensive day rate consumption

But with currently still very high battery prices and limited battery lifespan, basically the cost of using 1kWh of battery cycling itself costs almost as much as 1kWh of buying electricity from the grid at peak rates. So even if you could fill up the battery partly for free with the sun and partly for cheap with cheap night rate, it still doesn't make economic sense

One consideration is if you plan to go battery in a few years time (when the price has come down significantly). You might want to consider having all the hardware (hybrid inverter, small battery) in place now to cater for installing additional big cheap batteries later. Particularly because you can now do so with a very generous subsidy

Doing clear sums is nearly impossible here as we can't look into the future. We don't know how long this subsidy will last, we don't know what the future price of batteries and other hardware is, we don't know the future price of electricity and we don't know if we will at some point get a (lucrative) feed in tariff (get paid for the electricity we produce that we are not using ourselves)

uck51js9zml2yt

unkel wrote: »

And before anyone else butts in - yes you can use the battery in the evening time for your peak electric consumption (before night rate kicks in) and yes in some battery systems you can load them up with night rate and use the cheap night rate for your expensive day rate consumption

But with currently still very high battery prices and limited battery lifespan, basically the cost of using 1kWh of battery cycling itself costs almost as much as 1kWh of buying electricity from the grid at peak rates. So even if you could fill up the battery partly for free with the sun and partly for cheap with cheap night rate, it still doesn't make economic sense

One consideration is if you plan to go battery in a few years time (when the price has come down significantly). You might want to consider having all the hardware (hybrid inverter, small battery) in place now to cater for installing additional big cheap batteries later. Particularly because you can now do so with a very generous subsidy

Doing clear sums is nearly impossible here as we can't look into the future. We don't know how long this subsidy will last, we don't know what the future price of batteries and other hardware is, we don't know the future price of electricity and we don't know if we will at some point get a (lucrative) feed in tariff (get paid for the electricity we produce that we are not using ourselves)

Based on the above, what's the optimum current system?

unkel

How long is a piece of string?

If I didn't have any solar yet and I got planning permission for installing more than the maximum 7 panels allowed under the current rules, then I would install a 4-5kwp solar PV system with a hybrid inverter and a 2.4kWh battery (smallest you can get) for around EUR6-EUR6.5k total cost to me after subsidy

And if I didn't have anywhere near that amount of cash, I'd buy all the parts myself and do all the cabling preparation work. Then get a roofer to install the panels if they are high up on the roof, and get an electrician to connect the system up. You can get a very decent 2kwp PV install for about EUR2.6k-2.7k (allowing for EUR500 labour for roofer and electrician). 3kwp for about EUR700-800 more

uck51js9zml2yt

unkel wrote: »

How long is a piece of string?

If I didn't have any solar yet and I got planning permission for installing more than the maximum 7 panels allowed under the current rules, then I would install a 4-5kwp solar PV system with a hybrid inverter and a 2.4kWh battery (smallest you can get) for around EUR6-EUR6.5k total cost to me after subsidy

And if I didn't have anywhere near that amount of cash, I'd buy all the parts myself and do all the cabling preparation work. Then get a roofer to install the panels if they are high up on the roof, and get an electrician to connect the system up. You can get a very decent 2kwp PV install for about EUR2.6k-2.7k (allowing for EUR500 labour for roofer and electrician). 3kwp for about EUR700-800 more

Take it that I won't apply for planning and won't install myself. .what's the best way of doing it.

Someone will be home during the day in a 161 sq meter bungalow

unkel

If you won't apply for planning, the max you can put in is a 7 panel system. You need to get some quotes out there!

wexfordman2

Been looking at the payback model on the seai website, and based on my system it is showing a generation of just under €600 per year in electricity, so €50 a month off my electricity bill.

My monthly bill at the moment averages on level pay at €130 a month, so based on the figures given, that should reduce to €80pm at level pay (once it settles in).

At a cost to me of 8k, then my payback is looking at 14 years, using basic calculations.

Now, a couple of things on that worth teasing out.

Seai calculations
1) I suspect the figures are deliberately cautious if not somewhat pessimistic.

2) The calculator uses max of 5kwp, my system is 6kwp.

3) The calculator does not include battery or does not allow for the battery in the payback/usage figures as far as I can seem

4) The calculator does not take into account the Eddi water diverter system in the payback model either.

So, for my setup, I think the seai calculations are a good bit off.

Taking those figures on boars however, at a cost of 8k to me, and generating €600 per year, thats an annual return of 7.5% which is way above what I would get if I left the money sitting in a bank account.

Anyone any thoughts on the above ?

unkel

I've never seen any cautious calculations about payback time on any website except from a few posters here and my own calculations

Most overestimate the self use and put far too high a value on some self use that should not be valued at the higher rate, sometimes not even at the night electricity rate but just at low as gas rates (when used for heating water) of just 4c/kWh, halving that rate again or bringing it even below zero if you have to buy and install additional hardware like an Eddi diverter

wexfordman2 wrote: »

Taking those figures on boars however, at a cost of 8k to me, and generating €600 per year, thats an annual return of 7.5% which is way above what I would get if I left the money sitting in a bank account.

This is it really. Your annual return is far higher than on any savings account. And after your payback period, your real savings will begin. If you plan to stay in the house for a long time, it is well worth it

And not to underestimate the favour you are doing to yourself, your family and everyone else by going renewables

wexfordman2

unkel wrote: »

I've never seen any cautious calculations about payback time on any website except from a few posters here and my own calculations

Most overestimate the self use and put far too high a value on some self use that should not be valued at the higher rate, sometimes not even at the night electricity rate but just at low as gas rates (when used for heating water) of just 4c/kWh, halving that rate again or bringing it even below zero if you have to buy and install additional hardware like an Eddi diverter



This is it really. Your annual return is far higher than on any savings account. And after your payback period, your real savings will begin. If you plan to stay in the house for a long time, it is well worth it

And not to underestimate the favour you are doing to yourself, your family and everyone else by going renewables

Thanks again unkel

With regards staying in the house for a long time, when I leave, it will be in a wooden box :-)

The payback from installers is way too optimistic, but the seai figures were interesting, I suppose my point/query was, that while the actual generation figures would be realistic, the usage figures don't consider the battery and Eddi. Havnt looked into in huge detail, but the seai calculations sheet is Xcel based and a bit of digging into how it works just the up some of the points I was talking about.

I suppose, usage/self consumption gets very tricky to estimate when you throw a battery and hot water diverter into the equation.

600 euro was a bit lower than I was expecting from a generation perspective, but as you said, the payback is still there, and payback is not the only reason for installing.

I've had the unfortunate luck of having both dishwasher and dryer fail in the last two weeks, so replaced them both with a++ rated machines (dryer is a heat pump one), son that ought help drop things down a bit also.

Here is another question for you, on the install side of things.

They will be installing/identifying "essential load" circuits so that my battery will keep powering these circuits in the event of a power cut.

I am considering lights (everything is led), water pump and a few circuits for broadband, phone charging etc (maybe a TV also).

Any tips/advice in this ? Freezer etc is a bit if a waste, with 5kw battery I am unlikely to get any decent fallback time out of it.

Latro

wexfordman2 wrote: »

Been looking at the payback model on the seai website, and based on my system it is showing a generation of just under €600 per year in electricity, so €50 a month off my electricity bill.

Is it considered in their calculations that you would never use anywhere close to 100% of electricity produced?
It would probably be somewhere around 50% I think. Perhaps even less.

unkel

Calculations do get very tricky but if you just work from the basics: your 6kwp presumably south facing and in Wexford will generate about 6MWh per year maximum

Up to you to put a figure on how much you will self use directly that you can't push to night rate (house base load) valued at 14c/kWh, how much you will self use that you could run at night (dishwasher etc.) at 7c/kWh and how much will go to divert (at maybe 2c/kWh) and how much will go to battery for use during peak (14c/kWh) and how much for off peak (7c/kWh). Some guesstimates here and you have your pay back. Do take in mind that your battery will probably not last as long as your payback period though :eek:

wexfordman2 wrote: »

They will be installing/identifying "essential load" circuits so that my battery will keep powering these circuits in the event of a power cut.

I am considering lights (everything is led), water pump and a few circuits for broadband, phone charging etc (maybe a TV also).

Any tips/advice in this ? Freezer etc is a bit if a waste, with 5kw battery I am unlikely to get any decent fallback time out of it.

That is very useful. The fact that your install company has suggested this to you and will implement it as part of your agreed deal, says a lot in favour of them imho. And yes I would include the freezer in this. Don't open the freezer doors during the power cut, and it will use very little electricity. Including it will prevent you from having to bin the contents after a power cut

Shefwedfan

Ok, after the storm last week by poor roof shed is a little worse for wear. The decision has come to re-roof it. As I have to go for the cost of doing it then might as well do it so it can take solar panels. Better to fill up that roof than the roof of house.

Now I am wondering which roofing have people used? Am I better with the box profile or the corrugated with the wavy finish, if you know what I mean?

I have asked Solarcity for some advice as well.....

No point putting a roof on and then finding out the connections cost a fortune to use.

unkel

Install on metal shed roofs is the easiest and cheapest way to mount solar PV afaik

Shefwedfan

unkel wrote: »

Install on metal shed roofs is the easiest and cheapest way to mount solar PV afaik

I think so, but I would guess from that image I need the box profile roofing and not the wavy(technical term) stuff.....

chuck eastwood

http://www.eqc.ie/products/profile-sheeting/

MW5Rs is probably what you need. I re roofed my workshop 3 months ago have seen my dad use this. For the extra few quid it's worth getting the fabric backing to stop condensation. To cover roughly 11M x 7M it cost me €2000 just for the sheeting screws and flashing which they will form to the angle you need.

Shefwedfan

chuck eastwood wrote: »

http://www.eqc.ie/products/profile-sheeting/

MW5Rs is probably what you need. I re roofed my workshop 3 months ago have seen my dad use this. For the extra few quid it's worth getting the fabric backing to stop condensation. To cover roughly 11M x 7M it cost me €2000 just for the sheeting screws and flashing which they will form to the angle you need.

I have 2 16ft sheds and would need 8ft lenghts.....



Currently on the shed roof is felt. I was talking to mate last night about condensation and he said not to worry and just screw it direct onto the felt and down into the ply. Currently it is just felt screwed onto plywood

unkel

Shefwedfan wrote: »

just screw it direct onto the felt and down into the ply.

Mountings for the solar panel rails? That's very unwise advise. Not strong enough.

chuck eastwood

Shefwedfan wrote: »

I have 2 16ft sheds and would need 8ft lenghts.....



Currently on the shed roof is felt. I was talking to mate last night about condensation and he said not to worry and just screw it direct onto the felt and down into the ply. Currently it is just felt screwed onto plywood

You could but you shouldn't. The sheeting should be raised by the Barton and not directly onto the only. You will have 50% or more of your roof in contact with they felt and no gap/venting between them. In my case I was replacing an asbestos roof sink started from scratch. If I was going to be mounting PV panels on mine I would want to make well sure I don't create any bridge that moisture etc can cross. It's not a huge area. Just put treated lats between the surface and new sheets

Shefwedfan

unkel wrote: »

Mountings for the solar panel rails? That's very unwise advise. Not strong enough.

Would it not? the ply is then screwed onto the rafters.....


I was thinking of stripping back the felt off the roof and expose the ply. Then screw the new roofing straight into the ply.



What would I need to add to that setup to make sure it would be strong enough?

unkel

Shefwedfan wrote: »

Would it not? the ply is then screwed onto the rafters.....

Ah ok. You failed to mention that before

Gumbo

Shefwedfan wrote: »

Would it not? the ply is then screwed onto the rafters.....


I was thinking of stripping back the felt off the roof and expose the ply. Then screw the new roofing straight into the ply.



What would I need to add to that setup to make sure it would be strong enough?

You would have to go through the ply and into each rafter with the fixing.
My opinion would be that the uplift pressure would be too much for the rails only fixed through the ply.

kig

I am looking to install a PV system to our roof, unfortunately the surface area available is quite small. I have had conflicting advice from different installers, and hope that someone can give me an unbiased opinion.

The one company, who I am reasonably happy with is predicting a 2800-3600KW/H annual output (our electrical use is about 4800-4900). Although it is not covering all our requirements, and in winter probably only 20% or so, I think we should be able to pay for the system with the savings (at current prices) in about 8 yrs. Another company which was recommended, has told me it's not worth even quoting on as the roof area is too limiting, and I am struggling to find others to even get back to me at the moment.

jkforde

do you qualify for the current grant? (PV +\ battery)

https://www.seai.ie/grants/home-energy-grants/solar-electricity-grant/

bullit_dodger

https://www.boards.ie/discussion/comment/118152358#Comment_118152358

Most people who install solar don't get 100% converage on the usage, for a number of reasons. Mostly during the winter months, while you will generate "something" on even the darkest of days.....that something is often barely enough to boil a few kettles. Let alone run a house. So no matter what size you have (unless you go MASSIVE like cover a farmyard shed) you will be importing something.

Couple of things to keep in mind.

• You can cover both roofs. You don't have to have it facing south either. An East/West split of panels, while not as great as south, gives about 80% of the generation, and it's still financiall viable. it's only really North that you have to watch out for.
• If you have a shed, garage that also could be used
• Finally ground mounting an array is an option too. Costs a little more as you have to buy the frame and usually sink a few concrete posts into the ground deep enough, but if you are in a rural setting and have a bit of spare land - this might be an option?

SD_DRACULA

https://www.boards.ie/discussion/comment/118152358#Comment_118152358

Yes be careful about the overly optimistic generation values.

Give https://globalsolaratlas.info/ a try and enter your address along with the system size and see if it matches what you were told.

Also even if you generate a lot in summer, chances are you cannot use 100% of it anyway and 20% in winter might not happen anyway weather depending.

kig

https://www.boards.ie/discussion/comment/118153540#Comment_118153540

Thanks for the reply, yes I'm sure that in this climate it would be very difficult to achieve 100% of our requirement. I was quite interested in the idea that we may be able to cover 50-60% of our annual requirement. Unfortunately we only have our main roof and the sunroom roof the rest of the roof is facing north so I don't think we would be able to use it, and our garden is quite small. I just got a bit of a wobble when the only other provider who responded said that it wasn't feasible.

kig

https://www.boards.ie/discussion/comment/118153442#Comment_118153442

Yes as far as I've been advised.

jkforde

https://www.boards.ie/discussion/comment/118157276#Comment_118157276

then imho just go for it, make sure they do the BER and grant application as part of the deal. just keep an eye on grant paperwork, retain final oversight of that, otherwise you may get into a game of application ping-pong with the good folks in SEAI 😭