Solar panels wiring future proof

Sparkobrien77

Hi lads,

Just wondering if any of ye could shed a bit of light on this subject, basically I've bought a house and will be rewiring it shortly and I'm trying to think of everything. I'll probably want to install solar panels down the line when I have a few extra quid but for the time being I'd just like to run the cabling and have it ready for when I want to install the solar panels.
Considering I've no experience in wiring these I'm looking for information on what's required spurs,controllers,time clocks etc...
Any help would be appreciated , thanks.

Risteard81

You will find the requirements for Solar Photovoltaic (PV) installations in Part 7 of the Wiring Rules.

Steve

Solar panels generate DC, this goes to an inverter to convert to AC for domestic use.

It depends where you put the inverter.

Apart from that, the only other thing I know for sure about PV, having looked at it a few years ago, is there is no cost vs benefit payback at all. The amount you generate / save will not cover the cost of the PV cell over its lifetime especially as you cannot export to the grid.

Sleeper12

Steve wrote:

Apart from that, the only other thing I know for sure about PV, having looked at it a few years ago, is there is no cost vs benefit payback at all. The amount you generate / save will not cover the cost of the PV cell over its lifetime especially as you cannot export to the grid.

Things haven't improved much since. Im a plumber and can install labour free and I still don't think I'd get any return. I've never met a plumber or electrician for that matter with solar panels in their own homes.

The thing to watch out for are solar panels for generating electricity I believe. I caught the end of a pat Kenny interview. The expert in the studio reckons as early as 7 year for break even and savings of up to a third off the electric bill.

Steve

Yeah, any research I did gave a 10 year payback on PV - which was over the suggested lifespan of the cells.
I went to a few 'ideal homes' exhibitions and got the hard sell from the suppliers but they all backed away slowly when I questioned them on this.

Risteard81

Steve wrote: »

Yeah, any research I did gave a 10 year payback on PV - which was over the suggested lifespan of the cells.
I went to a few 'ideal homes' exhibitions and got the hard sell from the suppliers but they all backed away slowly when I questioned them on this.

The panels should last more than 10 years - probably more like 20. The first thing to go (and the most expensive) is the inverter. This might have a lifespan of about 6 years or so - not very long anyway.

Sparkobrien77

Thanks lads for the advice so just to round it up , ye think there not worth the hassle as it will take 10 or so years to pay for itself and by that time the panels will probably be on their last legs ? I would of just wanted them for heating the water, I thought there would of been big savings over the course of four or five years as to using the gas boiler ????

Steve

Sparkobrien77 wrote: »

Thanks lads for the advice so just to round it up , ye think there not worth the hassle as it will take 10 or so years to pay for itself and by that time the panels will probably be on their last legs ? I would of just wanted them for heating the water, I thought there would of been big savings over the course of four or five years as to using the gas boiler ????

Are you confusing PV (solar electric) with direct solar water heating?

Solar water panels are well worth the investment and will save you a fortune, they are two totally different things.

Ah gents, few things;

Solar has come down in price substantially in the last few years thanks to other countries incentivising them and seeing their worth.



The energy payback of PV is aboot 4 years. They last indefinitely (some first roll out modern panel installations are still producing) they are rated to 80% of new energy conversion rating after 20 years and warrantied same. My 550Wp system is on track to pay for itself in 4-5 years.
Decent inverters last 10 years.
I've one grid tie inverter and two battery combi jobs all of which I paid about 20% RRP for just by being patient.

You can heat water without an inverter.

Solar PV is quickly becoming a more reliable and cost effective energy source (if less efficient) than solar thermal.

There's very little you need before install. It's just panel -> local isolator -> DC breakers if there's a danger of over-current which is not as prevalent as commonly thought - > accessible isolator -> inverter -> circuit protection -> grid, and some CU stickers.

Stick 2 x single core PV cable 6mm² tailed beside your distribution board going to the east roof and another 2 x single core PV Cable 6mm² to the west roof; job done, present proofed!

Diverters for water heaters can be installed easily they just watch Δ voltage and have various means of proportional load control, some better than others.

I find it very disheartening that above mentioned sparks don't value the merit of home-grown power. Are we all so content with coal? Surely a sparks installing his own panels would make a substantial saving on installation moreso than Joe Public?

Sparkobrien77

Sorry lads I suppose I should of made it clear that I was on looking for advice on solar water panels my mistake 😬 So what kind of wiring should I install for the solar water panels to future proof it ? Obviously a power supply to attic I presume and I'm assuming there will be some sort of controller like you have on your ordinary heating system i.e.: 2 channel timeclock etc.. any help is appreciated,cheers

Sleeper12

Sparkobrien77 wrote:

Sorry lads I suppose I should of made it clear that I was on looking for advice on solar water panels my mistake 😬 So what kind of wiring should I install for the solar water panels to future proof it ? Obviously a power supply to attic I presume and I'm assuming there will be some sort of controller like you have on your ordinary heating system i.e.: 2 channel timeclock etc.. any help is appreciated,cheers

The pv panels would be a much better investment. Money back after 3 or 4years compared to 10 to 15 years. These not only heat your water but can provide free electricity

Steve

Sparkobrien77 wrote: »

Sorry lads I suppose I should of made it clear that I was on looking for advice on solar water panels my mistake 😬 So what kind of wiring should I install for the solar water panels to future proof it ? Obviously a power supply to attic I presume and I'm assuming there will be some sort of controller like you have on your ordinary heating system i.e.: 2 channel timeclock etc.. any help is appreciated,cheers

AFAIK, all you need for them is a circulating pump and maybe a pipe stat. I'm not sure so will defer to those that have more experience.

Steve

Sleeper12 wrote: »

The pv panels would be a much better investment. Money back after 3 or 4years compared to 10 to 15 years. These not only heat your water but can provide free electricity

How do you figure that?

The big bugbear in Ireland is you can't export (unless that has changed) so it means while you can generate during the day when you don't need it, the excess is wasted. At night when you are using power, PV is useless. If there was a way to store it, maybe, but there isn't

Using PV to heat water is many times less efficient than direct solar water heaters.

You can export, it's the principle of grid tied micro-generation, the grid is the battery. Power leaves your inverter at a voltage higher than the grid and goes to a load be it in your house or your neighbours'. Pretty simple really. The actual problem is Ireland likes a closed shop and nobody will pay you for it and is looking forward to heavy fines for not complying with it's obligations to meet the EU Renewable Energy Directive...or maybe it will by privatising huge solar and wind farms and cutting out the micro-generators who are actually using it while loading up all the spare grid capacity.

So this leaves us with the only economic systems on this island being self-consumption; high tech. water heating and base load compensation. Which has a longer payback because you still have to fork out for a scaffolder, roofer and sparks.

PV is zero maintenence, factor in the cost of changing the eco-glycol in solar thermal and the upkeep of a mechanical system and you'll arrive at a more realistic comparison. PV is ~20% efficient at converting photons to electrons, solar thermal is ~70% efficient at converting radiation to thermal.

At the end of the day that's just a question of roof space. PV has the added advantage of being useful for electricity too and far easier to throttle.


However you can install a DC coupled extra low voltage system ground mounted and save a pretty penny. No sparks required (not restricted works ). No scaffolder, no roofer, 20Ah battery to just signal load controllers (ELV immersions, voltage sensing relay driven loads etc). Simples!

Steve

I'd love to see actual data on that. I did a fair bit of research a few years ago and it wasn't viable.

BTW, the fact that you cannot export home generated power to the grid is a legal matter, not a technical one. If you pay a few million for a license then you can.

rolion

Hi,

I have both systems installed.
DIY story HERE and more info on both panels technology HERE .

You can see my live data here:

Solar Tubes

PV Panels

Both systems are working fine and after i will manage to g€t my hands on a solar diverter,i can "export" to my cylinder immersion heater all the extra enegy generated by the PVs (until FiT kicks in).


PS
Im keeping an eye from time to time HERE .
Selecting Ireland,i can se how other systems are performing in the country on same day.
There is a 14Kw one...nice one !

rolion

Steve wrote: »

I'd love to see actual data on that. I did a fair bit of research a few years ago and it wasn't viable.

BTW, the fact that you cannot export home generated power to the grid is a legal matter, not a technical one. If you pay a few million for a license then you can.

I'm exporting to to the grid now! For free...that's why you will need a diverter from electrical PVs to hot water Panels/Cylinder!

One of the issues is that the inverter has to be certified as per Irish standards.
Then,a lots of wring certifcate if you need to install the import/export meter.

Steve

rolion wrote: »

I'm exporting to to the grid now! For free...that's why you will need a diverter from electrical PVs to hot water Panels/Cylinder!

One of the issues is that the inverter has to be certified as per Irish standards.
Then,a lots of wring certifcate if you need to install the import/export meter.

Really?

How much do you get paid per kWh that you sell back to ESB??

I know the tech side of it, it's the red-tape side that has always got me.

rolion

Steve wrote: »

Really?

How much do you get paid per kWh that you sell back to ESB??

I know the tech side of it, it's the red-tape side that has always got me.

I'm not getting paid at all !
Even more,due to a small issue with the meter,i had to pay for my own consumed AND generated electricity !

The FIT tarif is closed down by the supplier(s).

Steve

rolion wrote: »

I'm not getting paid at all !
Even more,due to a small issue with the meter,i had to pay for my own consumed AND generated electricity !

The FIT tarif is closed down by the supplier(s).

And that was the point I was making!

If you got paid then it would be worth it... The feckers in this country don't allow it so why bother at all?

I spent £300 on a 550Wp G83/2 compliant system, it's small enough I'm pretty much guaranteed self consumption without any fancy engineering.

Sleeper12

Steve wrote: »

How do you figure that?

The big bugbear in Ireland is you can't export (unless that has changed) so it means while you can generate during the day when you don't need it, the excess is wasted. At night when you are using power, PV is useless. If there was a way to store it, maybe, but there isn't

Using PV to heat water is many times less efficient than direct solar water heaters.

If you get solar panels to heat hot water all you'll ever get is hot water. PV panels give you free electricity & hot water. The immersion heats the water for free.
If you are not in the house midweek during the day you can have washing machine, dishwasher, immersion etc on timers. First timer immersion for 2 hours, 2nd timer washing machine 2 to 3 hours. third timer dishwasher for 2 hours. Weekend you might be home Sat & Sun. Well whatever you are doing then can be free. Hoovering, ironing, electric lawnmower, PC etc. Rechargeable batteries are on the way. They have been using them in the states for years now. this can give you free lighting at night.
Without any batteries they recon PC can cut your electric bill by a third. Thats a hell of a lot more than you'll ever save with solar panels.

My knowledge is very limited on PV but it is the way of the future. It's something I want next on the list. People will be scratching their heads in a few years wondering why the heck I paid out all that money just for free water & my mate is getting free power & water.

Sleeper12

Sleeper12 wrote: »

Rechargeable batteries are on the way.

They're here, have been here for decades. There's just a newer, lighter, more expensive type seem to be fashionable at the moment.

Steve

Sleeper12 wrote: »

If you get solar panels to heat hot water all you'll ever get is hot water. PV panels give you free electricity & hot water. The immersion heats the water for free.
If you are not in the house midweek during the day you can have washing machine, dishwasher, immersion etc on timers. First timer immersion for 2 hours, 2nd timer washing machine 2 to 3 hours. third timer dishwasher for 2 hours. Weekend you might be home Sat & Sun. Well whatever you are doing then can be free. Hoovering, ironing, electric lawnmower, PC etc. Rechargeable batteries are on the way. They have been using them in the states for years now. this can give you free lighting at night.
Without any batteries they recon PC can cut your electric bill by a third. Thats a hell of a lot more than you'll ever save with solar panels.

My knowledge is very limited on PV but it is the way of the future. It's something I want next on the list. People will be scratching their heads in a few years wondering why the heck I paid out all that money just for free water & my mate is getting free power & water.

Sorry but I remain skeptical for now.

I'm not saying PV is a bad thing, just that it is still a ways off being economically viable.

All the appliances you mention *that I currently have* cannot be run on a timer, they all 'fail safe' in a power fail and will not automatically start if a timer powers them up.

As to cutting 30% off your bill, even if you used next to zero units, you can't do that. Most of your bill nowadays is carbon tax and PSO tax (daily rate). If you use too little you also get penalised. Domestic units consumed account for only a small part of an energy bill. Couple that with the fact that they don't want home generation at all because it is illegal for you to export....

Ir reeks of supporting the providers and it sucks big time.

Water John

PV is def the future proof way to go. Hopefully in 2017 Govn't finally get to base with a suite of RE FIT's as promised.

PV panels dropping massively in price.
The economics of solar I would seriously question. My memory on the figures was about a €170 saving per year. That's not a good return on capital spend.
If you do go with them I suggest using a PV panel to drive the pump. No issue then with electricity outage.

Steve

Washing machines, driers and dishwashers are attended appliances.

It's not illegal Steve If you get a sanctioned system tick all the boxes and pay for an export meter which are stupidly expensive here compared to other countries and an "Irish standard" grid tie inverter that is compatible with the Irish grid and you'll find down the road often the inverter they made you buy drops out because the grid is incompatible with it.

As for the data you seek this site is pretty good for number crunching.

Steve wrote: »

All the appliances you mention *that I currently have* cannot be run on a timer, they all 'fail safe' in a power fail and will not automatically start if a timer powers them up.

What do you mean by that? Under normal operation there is no service interruption.

Sleeper12

Steve wrote:

Sorry but I remain skeptical for now.

I'm still only researching it myself and I'm not very knowledgeable on the technical side of of it. I suppose the big thing will be these batteries. How much can they store etc. Our electricity bill averages 150 per month.. We spend a euro per day on hot water so I would hope to save around 50 per month in total. I'd settle for a saving of 50 for summer months and 30 for winter months.

Water John

Sleeper, correct on your €365/year for the hot water. Solar panels would save you about half that.
We are, slowly going the route of smart meters. This is where the flexibility of PV will come in. The export price of surplus may not be high as it looks like there will be a good lot of PV commercially installed, but it may not be financially viable to install large storage. However, second hand EV batteries will find a function in this area, I suspect.

A battery can store as much as it's rated to store, it's modular.

Batteries, inverters, chargers, charging losses, inversion losses; unlikely to ever be more cost effective than grid tied.

Sparkobrien77

Thanks lads for the advice much appreciated