Solar PV, is it worth it?

Kealyboy

Hi, I am interested in installing solar PV panels to my home. I live in a 3 bed semidetached house. Just the two people live here I got a quote for 10 solar PV panels (10no 430W Jinko N-Type PV Panels, 30 year performance warranty, 25 year product warranty- 4.3kW system) and 5 kW battery after grand cost is coming out as €8100. My electricity charges for the last year was coming in at around €600/€700.

would you think it would be worth getting solar panels?

I was thinking long term of maybe getting an EV charger fitted also, as I will probably upgrade to an EV car within the next year and also considering heat pump in the near future and having them interlinked.

What’s your thoughts?

thank you

the_amazing_raisin

Yes, it's worth it, absolutely 100% guaranteed

Just get multiple quotes and compare them to the quotes thread to see if you're overpaying

jkforde

Yes, do it, just choose wisely....

Kealyboy

Is the hot water diverter a good option also or would I be better off just selling back any excess to the grid

Busman Paddy Lasty

Yes it is worthwhile.

What I've gleaned from the forum is that a battery without grant has a very long payback time. You could get very cheap night rate like 5c to charge at night, could save €1 per day. You could ask for your quote without battery and see what price it comes in at. Put saving towards EV.

If your car is parked at home during the day and is an EV you don't really need a house battery. Some chargers can divert excess to your EV.

Hot water diverter apparently won't pay for itself. For example if you have night rate, boost hot water tank with sub 10 cent electricity. In daytime export to grid at 24 cent and you're already aware of that.

TLDR battery and eddie probably not good financial decisions.

jkforde

request a D\N smart meter if you currently have a standard D\N meter and then charge battery during the night rate (3hrs, 9hrs, etc), sign up to a provider with decent export tariff. I wouldn't bother with a HW diverter, they're nice to have but in hindsight not necessary and will unnecessarily delay ROI payback. most importantly, go for it.

Chris_5339762

Agreed that the HW diverter is probably a luxury that doesn't pay for itself, but we have one and it is such a useful thing to have. Hot water is an absolute must in any house and having lots of it freely available is nice. Its always "the free hot water" even moreso than "the free electricity"

yankinlk

https://www.boards.ie/discussion/2058315078/solar-pv-is-it-worth-it

OK IM going to go the other way here. I have and love my solar - but its 10 year investment. 600/700 is that per bill x6?? or for the entire year? 600 x 10 years is 6000. UNless you plan to ramp consumption and also make sure you are settled in that house for a good few years... otherwise skip it. You can still reduce reuse recycle and save money on tariffs etc... unless i have your figures confused. :)

billy_beckham

600 yo yo's a year?? That's very,very low...with falling prices I'd hold off on investing, seems to be a lot of gouging at the moment...

Puffster

If you've got Oil/Gas for HW then you should be able to save 15-20% a year on that bill using an Eddi/similar, which then reduces your ROI time

graememk

The price of 8k is high, would like it a bit lower, closer to the 6k mark. (Or even less if you ditch the battery.

https://www.boards.ie/discussion/comment/121149740#Comment_121149740

No it won't. If your focusing on ROI

Eddi is an extra cost of at least €500. Say if your oil and gas was 15c/kWh (gas is more like 10c) you'd be better off heating your hot water with oil/gas and exporting the excess at 24c(what most suppliers are at now).

Ignoring the export for a minute, and focusing on ROI:

At 15c, just to pay off the eddi needs you to put 3300 kWh through it, before it will touch the ROI of the actual solar install.

Eddi and other diverts have their place, in convenience[and smug mode from heating from the sun] more than actual cost savings.

Eg if you currently heat via an immersion only, it will help a lot or heat your hw from solid fuel, means not having to light a fire in summer just to have hot water.

JayBee66

https://www.boards.ie/discussion/2058315078/solar-pv-is-it-worth-it

We are two people in a bungalow; 6.4kW of panels NE/SW, 5kW battery and inverter. No electricity bills since installation in February 2022. What is there not to like about that? Since we installed, everyone in the countryside surrounding us is now doing it. We are the original Jones's.

We are producing so much electricity our utility owes us 1400 in credit, which we'll use to heat the house with this winter.

You might want a diverter for the immersion heater or you could save the money for an electric radiator. We have solar thermal for most of the year. We don't use a diverter in the autumn/winter. Instead, we just put the immersion on a timer and have it on during the night with cheap imported electricity but more often than not there's enough PV during the day to turn on the immersion and give it a boost to between 40C and 55C with a once a fortnight boost to 65C for legionella. I see many people constantly topping up their tank, which I think is wasteful. In the winter we use an electric shower, which if used around midday might drain 100W from the grid.

Having so much free electricity means we use far more than we ever did. Mostly running desiccant dehumidifiers all year. Less damp makes a hot house feel cooler and a cold house feel warmer. A few ceramic core radiators will supplement wood heat in the winter.

We are not going to bother with an electric car until they are ubiquitous and the cost of insurance is much lower. I am retired and don't need a car. She Who Must Be Obeyed has a cheap Yarris. Money is our metric not being Green. I think it's too late for saving the planet.

bullit_dodger

https://www.boards.ie/discussion/comment/121147111#Comment_121147111

The battery decision is interesting. With some of the rates out there at the moment the payback timeline for a battery is fairly reasonable. Depends on the supplier/rates/your consumption, but many people would see 5-6 years for payback. Fill the battery at cheap night rate and then use that yourself during the day and/or export deliberately what's left. 10Kwhr battery could see you "make" or "save" €2/day. After your 5-6 years, your quids in and ahead. What's more in winter, a battery will soften your bills (when they are highest) by €30-40/month.

I'd also echo the thoughts about the Eddi. Financially it will probably never pay for itself, but if I was shopping myself again in the morning for a solar installation, I'd get one again. I just like the fact that for 8-9 months or so I have hot water on tap (excuse the pun) and available. Yeah I know it's not smart money, but its not all about money.

Busman Paddy Lasty

Correct it's not just about money. If I had a hot water tank I would get an Eddi for convenience.

At home we got a battery as an experiment to see if we can use <1 unit per day during the good months. Not possible without a battery.

At decision time there was no FIT and the margin between D/N rates wasn't as wide as now. We have the option of dodging peak rates too. Also at decision time I didn't know you could stay on MCC01 on a smart meter and certainly didn't predict 24c FIT and now Pinergy's 5c night rate. Smart rates were scandalous at the time and i thought we'd be forced onto rip off rates.

average_runner

We are getting quotes at the moment but they all seem all over the place, some companies really bad reviews on google, others with only 2 month old reviews.

Looking at getting 10 panels, 5kwh battery and zappi for the car. Two more calling out this week and then we make the call on who we go with

bullit_dodger

https://www.boards.ie/discussion/comment/121153528#Comment_121153528

10x panels @ 400 watts each will put you at 4Kwp. 100% recommend that you get solar, but with 4Kwp, you will struggle to generate enough to electricity even in the summer months to supply the house, fill your battery and then put into the car on all but the most exceptional sunny days. Meaning that your Zappi will be effectively unused for 330+ days of the year.

You'd be needing 6Kwp (or more) in panels before the car is a realistic option. With 6-7Kwp there are members on the forum who have been driving around on sunshine since early April! If you can't fit that on your roof, I'd probably drop the Zappi - but curious as to what the EV owners reckon as I don't have an EV

micks_address

https://www.boards.ie/discussion/comment/121153848#Comment_121153848

yeah i have 7kwp, 4 south east and 3 north west... north west panels will be largely ineffective from mind october to end of feb/early march. I have a zappi.. and last week was able to put 20kw into the car on a sunny day.. the best days im seeing this month are max 20kw.. id say i won't be putting much solar in the car over winter at all.. i dont drive every day so i can leave it plugged in and see how it goes.. in the summer months can definitely charge it more.. but id say the most consistent ive seen going into the car is probably around 3kwh from solar excess.. so granny charger speeds.. if you need to fill in a rush.. its unlikely solar will cut it.. been a few nights i topped up between 2am to 4am on cheaper rates.. when i knew id be going some where.. that said its nice to have the complete solution...

DC999

https://www.boards.ie/discussion/comment/121153528#Comment_121153528

I’ve a Zappi but it’s not going to be needed now once I move to a smart meter. I’ll get a cheap night rate (5-8c depending on provider) and fill the car on that every night and get ~20c FIT for exporting unused electricity.

If you’ve A) already got an EV charger that you can set a timer on or the car lets you set the timer (pretty sure they all do) B) AND you have a smart meter, then scrap the new Zappi. ~1.5k supply and fit and you won’t get the €600 grant if you’ve a charger already.

2) Use that saving for more panels as bullit says. I’ve a 5kWp which is our roof maxed out. If I could fit more I would in a heart beat. I'd be paying an embarrassingly low amount for electricity (while FIT is so high). And that would include charging our EV. 

No need for an Eddi to heat hot water either. Time the immersion for cheap night rate.

micks_address

https://www.boards.ie/discussion/comment/121154411#Comment_121154411

Who's doing 5 to 8 cents night rate?

Busman Paddy Lasty

Pinergy 5c night rate.

*Assuming very high day or standing charges.

average_runner

https://www.boards.ie/discussion/comment/121153848#Comment_121153848

Thanks for that. Our thinking was the following but please, all recommendations are welcome.

We were looking at 400/430 panels x 10.

Our water is on a combi boiler so keeping that there.

We have a smart meter and we work from home. So we were thinking of the following:

Charge the 5kwh battery on the cheap rate at night time and use that in the morning in the house until sun comes up and gets going.

During the day the car will be plug in all day so can charge when we are here, won't get full charge but would get something?

Night time it required we can charge the car during the cheap price, but the cheap price only lasts for 2 hours?

Summer weekends we will sell to the grid as won't be here.

Our house is South East facing, in the summer we 4 hours sun on the back, but recommendations are not to put any on the back?

Is my thinking all wrong?

yankinlk

If your arent around n the summer months to use it - i cannot say it makes sense to invest in solar. Best month is May. April OK AUgust/Sept tail end of good generation. If you are installing solar to power a car in winter... waste of money.

average_runner

https://www.boards.ie/discussion/comment/121155017#Comment_121155017

Just the weekends, be here during the week all the time

joy123

https://www.boards.ie/discussion/comment/121154411#Comment_121154411

My understanding regarding putting more than 7.5kwh solar panel(18x 400W PV) doesn't really make any sense , because of bottleneck 5kwh inverter(max inverter we can put currently). or am I wrong?

micks_address

https://www.boards.ie/discussion/comment/121155556#Comment_121155556

well like always it depends.. technically you can only earn 200 euro from micro generation before you should declare it for revenue.. if you have 2 people on the bill that probably goes up to 200 euro.. like DC says i was tending to export everything and use 2am to 4am for cheap electricity.. but for the summer months there was days i was exporting over 30 kwh.. dont get me wrong its great.. im still in credit with EI and probably wont have a positive bill until november.. for the summer months i didnt mind using some more of the solar to charge the car, or doing the clothes washing/dryer when its never stopped raining etc.. from a pure financial perspective the most sense is probably export everything... don't have a battery and your export covers the cost of peak period use.. we have an eddi and we use the gas to heat the tank for an hour in the morning.. and then let it top up the immersion the odd time during the day. the 2 hours at night will only put 15kw into the car.. which is normally fine but we tend to do more day trips in the summer so i topped it up more from solar just to be ready to go... i could have exported that instead.. but needed to charge the car somehow.. so what was your question again :)

more than 7.5 kwp... totally depends... how much of it will get sun during the day and for how long? ive 7kwp.. but only the back gets the morning/midd day sun and evening gets the rest.. and the evening gets nothing in winter as its north west facing.. its never generating 7kwh at any one time

Caspero

https://www.boards.ie/discussion/comment/121155556#Comment_121155556

The bottleneck is really the power supply - ESB limit what you can put in on a single phase supply. The inverter size is driven by the max size you're allowed by the ESB. If you happen to have 3-phase you can put in more. We have 11kwhp on a 3-phase.

DC999

https://www.boards.ie/discussion/comment/121155556#Comment_121155556

You’re clued in and are looking at over panelling. That’s good! I’d suggest get the max the inverter can handle (and your pocket can take). Installer can confirm what that is. Let them decide as it can kill the inverter is not sized correctly. That might be higher than 7.5kWp, especially if you've an E/W split.

Then your ‘engine’ is bigger. That means on the best days you’ll max out / ‘clip’ at 5kW. But unless it’s pure south facing that’s unusual. But overall that clipping ‘loses’ very little production over the year. People here have done ‘the maths’ on it.

I’ve 4.9kWp across E, W and (tiny) S. I never get above 3.5kW – on the best blue sky days of the year. And even a sustained 3.5kW is as rare as hens teeth - just the blue sky days. So for my setup, the inverter is never the limit. Here’s my best production ever in May (and sitting just at the 3.5kW output for a few hours). When your clipping at 5kW it will show a straight line instead of the slight curve I have at the top here.  

spaceHopper

Folks this is a great thread, I'm learning lots.

My house faces Back: ENE Front WSW we've a new ish gas boiler and 300 ltr HW tank, house was renovated in 2018. The back gets good sun in the morning, we've to close the blinds to avoid overheating is summer. The front gets good sun in the evening. We're the northern part of a semi-D so only two useful roofs, unless you want to count a flat roof.

Two diesel cars, could change one to electric but not in the next 3 years.

When we did the renovation we installed a pipe for therma solar to future proof it.

Last 60 days we averaged 9 to 10 units a day of standard rate electricity. Don't know the gas, we use it for HW year round and heating in winter. In the summer half an hour at 5am gets us close to 50C. Two adults to kids under 11 so kids will start needing more showers soon.

Thinking of HW and PV on back and PV on front. Am I mad?

DC999

https://www.boards.ie/discussion/comment/121158748#Comment_121158748

Go for it. Amount you use per day matters less now that we’re getting paid 20c+ for units sold back to the grid. Just need a smart meter for that. So you get credited for unused power. Meaning low usage houses aren't 'saving' less.

2) Use the flat roof, I got 5 panels on that. They are about 1m x 1.7m in size.

3) Houses will only need more solar as we move to EVs, electric heating…An EV driving like Miss Daisy in a city will use about 2000kWh a year. Electric heating eatsss electricty unless you get a heat pump, and even they are heavy.

4) In terms of setup are you asking about solar thermal for hot water on one roof? And then solar PV for electricity on another roof(s)? That’s less common here but some have that setup like @Jonathan and @unkel. But…afaik most installers now aren’t interested in solar thermal for hot water. Solar PV is the ‘new toy in town’. So you might find the costs are high, or interest in quoting are low. But lets see what the people using them recommend.

spaceHopper

https://www.boards.ie/discussion/comment/121158824#Comment_121158824

Thanks, I think I'd put, thermal and PV on the back and PV on the front.

bullit_dodger

https://www.boards.ie/discussion/comment/121159304#Comment_121159304

Personally I'd skip the thermal side of things. Use the space that you have for PV panels. It's not that thermal is bad or anything, but it's so much more complicated than PV (which you already will have). PV gives you the best of both worlds. The energy your capturing on that part of the roof with a PV panel can be used to power the kids xBox, or cook the dinner, or heat the immersion. The energy that you'd get with a thermal can be used to heat hot water, and only hot water. Pipes sometimes need maintenance, etc.

People like unkel and others have thermal because 10 years or so ago, thermal pipes were WAAAY more cost effective than PV panels. PV panels collapsed in price (like 90%) over that 10 years, and now your just better off going the PV route. People who have a working thermal system would be nuts to get rid of it as it's working, as in why throw out something that works.....but if your starting from scratch it's just not worth it (IMHO). I'm sure others would have thoughts here.

On a more general level spacehopper I'd try to get a handle on where EXACTLY your power is going. Your bills are a good start. Graph them over the past 12 - 24 months and see the seasonal change. As others have mentioned, install an energy monitor and log the daily results along with the temperature that day. Turn on the heating system and threaten to break fingers (joke) anyone who messed with the thermostat for 3-4 days so you can get a feel for what it uses when you know the settings.