My solar savings have peaked - I Think !

Big Lar

Bill_1708786999_redacted.pdf

I have been looking at my recent bill this morning and as this is over the two bleakest months, I think that I have done well and everything should be better from here until next November.

Actual Electric Ireland Bill   

€134.63

Credit Amounts:

·        FIT €381.11

·        Government Credit €200.00

·        Electric Ireland Credit €50.00

The bill should have been:

·         €765.74

Other Savings not included in bill (Figures are approximate below 10% saving then plus 9% vat- Meh)

Generated 602Kwh of Solar: @€0.42 = €252.84 savings

Battery charges and discharged approx. 15Kwh daily over 64 days, 960Kwh saved @ €0.21 €201.60

If I had no solar, no batteries or free credit the bill should be:

€765.74 + €252.84 + €201.60 = €1,220.18 Which I am delighted about 😊

We cant seem to reduce electr

icity usage any more – Dishwasher and washing machine goes on at 6am

I can’t see any other savings to be got in batteries as I used only 245 units by day and this was probably the days that the extra load of washing went on or the oven was flat out or just a full house over Christmas

Have 6Kw inverter, 8Kw Solar Panels & 20Kwh battery pack

So what else can I do I wonder, Is there any more of a return to be got in investing more in solar ?

kippy

How big is your house? What type of heating are you using? How many people live in the house?

That is a massive electricity bill (€1220) if your figures are accurate!

Galego

That's pretty good! Excellent!

Few notes for you if you are keen on cracking up the numbers a bit more.

Are you sure 960Kwh went in and out of the battery? That'd mean 100% efficiency in between inverter/battery/cables/AC/DC/AC which in reality is more around 80-90%

602Kwh of Solar. Is that all entirely self-used through house loads or went through battery some of it? Again if through battery then there'd be some losses.

They may not get at all about the answers to the above questions but thought i'd ask in case you want to get a more accruate savings amout.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120149469#Comment_120149469

You'd be horrified at my bills then, I estimate without solar, batteries or government credits I'd be paying ~€3,500 per year when my discount expires in May

Thankfully the solar is getting installed next month, and the battery will be ordered soon after 😁

ELM327

You have the same setup as I currently have. 8kWp, 6kW,20kWh.

My account is in credit. There's always more savings to be had. For one, you're on the wrong tariff, with the wrong company. Secondly, you're using too many day units. You used 245 day and 2445 night. In my last bill I used 40 odd day units and 1800 night. I had 1.5 EVs for that bill period (sold our second car half way through).

Changes you could make for more savings would be to reduce those day units. You have 20kWh of storage, if that's not enough for your day units then get more storage. I would also evaluate your usage in general, as we have a 6 bed house with 2 attached offices, two techs working from home full time with all the coffee machines the shop had, gaming laptops, consoles etc. We have some electric rads to supplement/reduce oil use. Yet my bill in terms of units is 2/3 of yours.

I see what you're saying about diminishing returns. But I'm not at that point yet, I'm still using 1kWh per day of day units. You are using 4kWh of day units on average and that's way too much to say youre done.

slave1

Your bill needs to be based off the cheapest provider out there as else you are overstating your numbers, a few minutes on Energia's website would provide these numbers.

You have 20% losses on battery in/out, items like dishwasher, washing machine, dryer need to be factored at night rate as this is when they should be used.

I'm not sure if you are charging the battery at night rate, again if so you will not be saving full day rate, you will be saving the difference between day rate and night rate less 20%.

You're 602kWh generation is exceptional for the last two months, the 20kWh pack is super (likely 16kWh usable) to take you off day rates

Big Lar

@kippy 3500sq ft on three floors is the house size and we use oil central heating, 5 live in the house and there is always someone home, have an EV also and this is responsible for 1400Kwh of the total.

@Galego The numbers are there or there abouts, appreciate that there are always losses but its within 10% of it, enough for a general idea

@ELM327 Stuck on that tariff for another 10 months I reckons so that cant change.

@slave1 Energia has a clause if I use over 2000Kwh per month the night rate goes up an extra 15c, so I dunno about that now Price Plans - Energia

Big Lar

I suppose the question still really is:

Can I do anymore with the solar that would be worth the investment ?

the_amazing_raisin

https://www.boards.ie/discussion/comment/120150898#Comment_120150898

More panels? Can't see more capacity ever failing to pay off, especially when we all get moved to smart meters and measured export

unkel

@Big Lar - "Dishwasher and washing machine goes on at 6am"

Be careful with that, some of them on ECO programs take longer than 2 hours, so you would either be using peak rates for that, or eat into your battery unnecessarily

@Big Lar - "Stuck on that tariff for another 10 months I reckons so that cant change."

Of course you can change at any time. Costs just €50 penalty for breaking contract. Done it myself. Your night rate is insanely expensive and with your very heavy use, that penalty is paid back in no time with cheaper units from Energia EV plan

For any of your calculations, you should only ever use the cheapest rate in the market. Also for PV production, you should only use the peak rate to calculate the value, for the units that you actually use at peak rate and could not use at night rate (this in practice is very little as most stuff can run on night rate / battery), so your calculated revenue / savings are inflated. Don't want to be a spoil sport here, but we need to properly assess our investments in renewables, not make the figures look nice, we are not out to be kidding anyone

ELM327

https://www.boards.ie/discussion/comment/120150898#Comment_120150898

Yes. You're using too much electricity in total, an dyour day use is too high, and as I outlined above you're on the wrong tariff.

Check what is using all the power. Pay the 50 quid break fee and move to Energia.

ELM327

https://www.boards.ie/discussion/comment/120151216#Comment_120151216

No point wasting money on panels, when there's so much he can do without any investment.

kippy

https://www.boards.ie/discussion/comment/120149511#Comment_120149511

The OPs estimate was for two months only.

3500 a year is about a grand a year more than my own usage. So not out of the ordinary depending on what you are using it for, size of house etc.

Have a relatively small 1600 sqft detached house. 2 adults and 3 kids. No one at home during the day. No elec car and oil heating which I'd spent 700 to 1000 a year on.

Big Lar

https://www.boards.ie/discussion/comment/120151334#Comment_120151334

I know exactly whats using all the power but thats the way that it is

• Have office with two PC'c, two laser printers,scanners and then there is a 24port POE switch with cameras and what not, and router and a 2nd switch with two small servers and all that's around 750w
• Easy to make up the rest of it

About moving to Energia

Please see below if you use more than 3,000kWh day usage & 2,000 kWh night usage every two months, you will be charged the rates below for only those units above that usage. Applicable discounts will be applied to these rates.

Now have second EV and expect night usage to be well over the 2,000Kwh bi monthly going forward so I am going to penalized an extra 13c a unit so I dont know if it will be really worth it

Big Lar

OK, Just signed up with Energia.

See how that goes

Nelbert

Based on your bill 2000 of those night units could be a good bit cheaper, 668 more than you are paying....

You'd probably still save with Energia.

I sympathise with the high usage (NAS, 48 port switch and a few other things beyond the norm myself). My background usage is 400w

I've made a concerted effort to consolidate on the IT side (most of my stuff suitable to run as docker containers on the NAS). It's worth seeing if it's possible.

DC999

As a comparision, our house uses under 3000kWh a year (excluding heating + cooking + EV charging). Certainly not trying to gloat as I know we're lower than most. 2 adults, 2 young kids. I'm WFH fulltime but that's 100w max. We turn stuff off when not using it. So you could turn off the printers and scanners until you needed them. I’ve some plugs that let’s you pick how long to turn it on for. Press once for 15mins, twice for 30mins …up to 8 hours. So could turn on the printer that way and it auto turns off after 15mins. Or could get a smart plug and tell Alexa to turn it on or off. Or just manually turn off and on when needed of course 😊

We’re close to 50cent for daytime units of electricity now for those out of contract. I’m damned if I’m giving that money away for free. There’s more our family could do with it.

Your home office baseload of 750w. And in winter that’s all good as it’s all providing heat. But could the warmer months, you’re paying for that power to turn into heat. As a comparision that’s heating our 5 x 5m meter sitting room / kitchen at the moment with an electric rad. 

unkel

@Big Lar - the penalty rate with energia is only for the units above 2000 per billing cycle. I do go over sometimes too, but not by an awful lot. So only a few units are the higher rate. Still only half of peak rate mind. The overwhelming majority are still at the cheapest night rate in the market (Energia EV plan). Glad you joined them, we should all always vote with our feet!

Big Lar

https://www.boards.ie/discussion/comment/120152520#Comment_120152520

Would you believe that I updated the printers from HP3800's to Brother HL-L9310CDW's over the past two years and am actually shocked that there is no physical off switch on the brothers, fair enough they only use 10w in sleep mode but like for both printers that almost 0.5Kwh per day just to sit there. You would think in these modern times that the brother lads would have a switch in them.

In the end of the day for the comfort of being able to run a business and work from home a constant load of 750w for office equipment is very acceptable.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120152079#Comment_120152079

Oh yeah I missed that bit

We've two EVs in our house plus heat pump and electric cooking, and always someone working from home

Last year's usage was 10,500kWh, roughly 45% at night rate

Although to be fair that's the entirety of my energy costs. If you factor the same in for petrol and oil or gas I'm still saving some money

Big Lar

https://www.boards.ie/discussion/comment/120152555#Comment_120152555

Be interesting to see how things will go as we have a second EV here in the house now, but hopefully as it will be at home most days it will get charged from the solar in the coming months.

Nov to Jan next year may be tough alright

unkel

Aye. Dreading my renewal in late August already but as you say, all of us with big PV setups and batteries won't feel the pain until next winter

graememk

Same boat,

Most recent bill was about 380, (not inc any gov grants)

70odd day, 2880 night!

Although that was the darkest months, with the high electric demand, and heating on night rate, even paying the 880 units at the high rate it was still cheaper than oil.

Once march hits, gonna be practically off grid.

creedp

https://www.boards.ie/discussion/comment/120152624#Comment_120152624

I know when people invest in solar, drawing from the grid can be considered the ultimate no no. However, another way of looking at it is that if this excess over generation is predominantly driven by EV charging, then unless you spent big to purchase the EVs purely to save on running costs, you are making big savings all year around compared to what you would be spending driving 2 ICEs. So in other words electricity, even if drawn from grid, is a really cheap way to run a car and if you were still driving ICEs, next Nov to Jan would be that bit tougher. So IMO focus on how much better a position you are now in having installed the solar.

DC999

https://www.boards.ie/discussion/comment/120153611#Comment_120153611

Well said!!

unkel

https://www.boards.ie/discussion/comment/120153611#Comment_120153611

I spent nearly €50 per week in petrol alone in my last main ICE car 7 years ago. That was nearly €2500 per year. Of course my electricity bill is several hundred a year more because of my EVs, but that massive petrol bill has disappeared!

And even a gas-guzzling hard driven Tesla Model S, averaging maybe 21kWh / 100km, driven 20k km per year (substantially more than an Irish average car does), using over 4MWh per year (substantially more than an average Irish house uses - not for heating), this only costs €300 per year in electricity based on my 7.9c / kWh night rate

creedp

https://www.boards.ie/discussion/comment/120154720#Comment_120154720

Exactly my point, if you can afford to buy an EV they cost pittance to run compared to an ICE. So instead of worrying about the cost of charging one people should be celebrating the massive savings and that's even without having free solar energy. My only regret is not owning one with a decent range!

unkel

Funny you mention "if you can afford"

Before I bought my brand new Hyundai Ioniq 28kWh over 6 years ago, I did some sums. They showed that the total cost of ownership of buying a brand new car (with in hindsight overly prudent assumptions about depreciation) was lower than keeping the old petrol banger. I had the money in the bank, not making any interest, but even if you had to take a loan out to buy the car, the figures would have been close.

This of course goes against all logic you were ever told by the man in the pub 😂

Big Lar

Great savings in owning an EV, the only problem is that you must pay up front for everything and get there savings bank over a few years.

monseiur

Hi Big Lar I'm contemplating a major re furb. on a 1950's bungalow to include solar panels etc. (Cheapest quote €78k. after all grants ! ) Can I ask what, in your opinion, is the approx pay back time on solar panels complete with batteries etc. ? I have been told it's 10 to 12 years depending of course on many variables. Will have to keep oil central heating as engineer reckons air to water is not feasible.

Thanks.

unkel

https://www.boards.ie/discussion/comment/120155402#Comment_120155402

How long is a piece of string? Depends totally on the size of your setup, your electricity consumption patterns, your electricity rates, how good a deal you got, etc.

FWIW I did the (conservative) sums for a friend with a recent almost €10k (after subsidy) install of a 6kwp system with 5kWh battery, family of 4 with EV and it was under 5 years, that said he is on a smart meter and smart tariff and his peak rate is about €0.50 / kWh

My own last DIY major upgrade (no extra battery) with very well bought parts had a payback time of not much more than 1 year (heavy electricity user)

creedp

https://www.boards.ie/discussion/comment/120155117#Comment_120155117

Those were indeed heady days and I really regret not buying one at the time!

the_amazing_raisin

https://www.boards.ie/discussion/comment/120155291#Comment_120155291

The way I think of it is if you're in the market for a new car then you're already prepared to pay money. So the real upfront cost is the premium (if any) for buying an EV

the_amazing_raisin

https://www.boards.ie/discussion/comment/120155402#Comment_120155402

As unkel mentioned it depends heavily on your electricity consumption. The more of your overall energy mix you can convert over to electricity, then the more you can self consume from your solar

So things like electric vehicles, electric heating and cooking can help in this regard

Since your engineer mentioned a heat pump isn't feasible (I'd double check this personally) that means heating isn't much of an option. However you could still look into an EV at some point, or using something like an Eddi to heat water with excess solar

For me, with everything electric, the sums are currently working out to an 8 years payback time with Solar panels and battery. We'll see how that goes post installation

the_amazing_raisin

https://www.boards.ie/discussion/comment/120154720#Comment_120154720

Just for a giggle I tried to work out how much I'd be spending with the house being heated and cars powered by dead dinos

Some very basic estimates put it at €1,500 for electricity, €1,840 for gas and €1,600 for petrol for both cars. Total is €4,940 per year

This is against around €3,500 per year if I do nothing, and around €1,200 per year with solar and battery taken into account (and before the government credit)

So over €3,700 saved per year potentially. That'll certainly make for a short payback time

slave1

Ironically (well mathematically) the energy crisis has vastly inproved our paybacks, if prices go back to what they were our Paybacks will extend

RoboRat

I have been pleasantly surprised that I was pulling in 18-20kw in Jan on the clear days. I had anticipated maybe generating 5-10kw, so I was very surprised. In January, I generated 170kwh to date, which is about 18% of my overall monthly usage and I expect that to be over 20% by the end of the month.

My energy from the grid from July (when installed) to the end of December came to €446 (unit cost only). My FIT should be circa €190 so the cost of electricity for those 6 months has been €256. The cost for the same period the previous year was €1590 and considering electricity is up about 44%, if I conservatively increase it by 25%, the cost would be €1988 for a like-for-like comparison. I'm looking at 5-year payback on my PV system now.

I'm getting an EV in Q2 and when I ran the numbers, it only costs an extra €100 per month for a brand new 2023 EV compared to keeping my current 08 diesel Mazda - this included bundling another loan with the new EV loan to the lower rate of 5.5%. I'm spending approx €260 on diesel a month, and the tax, insurance, and servicing costs are higher.

All things said I'm delighted with the PV panels and how efficient they are - great investment :-)

unkel

@RoboRat - "I have been pleasantly surprised that I was pulling in 18-20kw in Jan on the clear days."

Wow, you must have at least a 50-60kwp install?

Friendly hint: get your units right ;-)

graememk

https://www.boards.ie/discussion/comment/120156183#Comment_120156183

A high angle south array can perform really well in Jan.

DC999

Moving to an EV saves us more than solar, but costs more too. So we got the EV first (2nd hand Leaf and waited until we were changing car anyway). Car cost 15k (plus 1.5k for charger). Then got solar later in the year. Solar cost ~8k.

For the EV, we’re saving around 1.5k a year (and that was before petrol prices went nuts. So 500 quid less on car tax. And 1k less on petrol - that’s including the electricity to charge it).

And with solar we charged the EV for free a lot of the year, until about mid Sept. Car needs to be in the driveway of course which isn’t the case for everyone.

unkel

Don't forget cheaper maintenance, cheaper insurance, cheaper tolls and likely much lower depreciation on EVs!

DownByTheGarden

https://www.boards.ie/discussion/comment/120156183#Comment_120156183

Im averaging over 10kwh a day so far in January.

Ive had a few days over 20kwh this month. Over 11kwh today (27th Jan).

Its an 8kw system.

unkel

https://www.boards.ie/discussion/comment/120166091#Comment_120166091

Averaging over 10kWh per day, wow! My system is about 11kwp, all pure south and I am nowhere near that. Got about 10kWh today. Mind, near half of my panels are very close to flat, so they don't do much in winter

DownByTheGarden

https://www.boards.ie/discussion/comment/120166182#Comment_120166182

My panels are all facing just south of SSE. 30 degree slope. Its been very sunny the last few weeks to be fair.

I think todays generation is just about finished at 11.4kwh.

This is from just now. Panels are there since the last week in May, so the total yield number only goes back to then. No point posting any other data from other days because the solis reports include the battery charging and make the figures totally wrong, but the ones below are correct.

Real-time Information

Status

Online

Current Power

0.033kW

Today Full Load Hours

1.9h

Alarm Information

No alarm 

inverter internal operating ambient temperature

20.4℃

(up to 105℃)

Today Yield

11.4kWh

Monthly Yield

282kWh

Annual Yield

282kWh

Total Yield

5.587MWh

DC999

https://www.boards.ie/discussion/comment/120166182#Comment_120166182

For those of us in suburbs, there can be more winter shade too with the low sun. From neighbours houses, tall trees....

slave1

https://www.boards.ie/discussion/comment/120166293#Comment_120166293

Tell me about it 😫

DC999

https://www.boards.ie/discussion/comment/120166869#Comment_120166869

Yeah, I've much solar envy when I see some of the S facing numbers :) I've E/NW and it gets hammered in winter.

unkel

https://www.boards.ie/discussion/comment/120166293#Comment_120166293

Small 3 bed semi in the suburbs myself. In a housing estate with other small 3 bed semis. Yet I have 32 full size panels up, all pure south facing, zero shading. Soon to add 12 north facing panels 😁

Big Lar

@unkel , Out of curiosity, More than two stings then, Will you need a second inverter ?

unkel

https://www.boards.ie/discussion/comment/120168856#Comment_120168856

I have 3 inverters 😂 Well, 4 actually. 3 string inverters and I have a wee micro inverter in operation too.

If I got the 9kW Sunsynk, I could get away with just 2 string inverters as it can handle parallel strings (up to 26A which is plenty)