Solar PV Hints, Tips & Troubleshooting

mp3guy · 10-02-2021 12:07PM

Solcast.com does that.

championc · 10-02-2021 10:36PM

graememk wrote: »

Only gives the total kWh, not what each string is outputting

But if you got a daily total of PV1 and PV2, can you not use the monthly graphs of the same thing you used for the daily stats ? I thought that you can do Daily, Monthly, Yearly and Total of all individual stats

graememk · 10-02-2021 10:53PM

championc wrote: »

But if you got a daily total of PV1 and PV2, can you not use the monthly graphs of the same thing you used for the daily stats ? I thought that you can do Daily, Monthly, Yearly and Total of all individual stats

Unfortunately it only has the daily total, (no CT on this inverter, so it doesnt know consumption etc)

Week still has the full breakdown though

graememk · 18-02-2021 06:56PM

So this popped up on my feed

https://www.energia.ie/plans-and-switching-info/ev

16.64 day, 4.78 INC VAT!

it says its for EVs, but if people are charging batteries at night, and having low day usage. Could be having some savings.

slave1 · 18-02-2021 07:33PM

Interesting, I have an EV Charge Point so can switch, currently paying 14.22c day and 6.82c night with 22% Day usage and 78% Night usage...if I was on this plan it would result in a 14% drop in my leccy (usage) costs

slave1 · 18-02-2021 07:35PM

Can't see any of the T&C's though, would need to see them, any caps, duration etc

KCross · 18-02-2021 07:47PM

slave1 wrote: »

Can't see any of the T&C's though, would need to see them, any caps, duration etc

Looks like there are no catches.... same usage limits apply as other Energia plans which is 2000kWh at night per billing period.

24. EV Tariff (Our Electric Vehicle Plan)
Eligibility:

New Energia Domestic customers with a Nightsaver Meter (Day/Night meter), either Dual Fuel or single fuel electricity.

Customers must agree to receive their bills online and pay their bills by direct debit to receive the full discount
The normal thresholds for nightsaver apply in terms of the kWh usage (Above 3,000kWh day usage and 2,000kWh night usage each billing period).

Contract length/Type

The contract duration is 12 months, after which the customer will revert to Energia’s standard Nightsaver plan.
The price of the electricity and gas unit rates are fixed for 12 months. Electricity rates (Day 0.2124 Night 0.0611) Gas 0.0550 Valid from 1st Feb 2021, until 28th Feb 2021.

The standing charges are subject to change in accordance with our General Terms and Conditions.

Charges/Discounts

Discounts apply for the contract duration and are against the Energia EV Tariff Our Electric Vehicle Plan, subject to the customer continuing to pay by direct debit and receiving their bills online.

31% Discount valid on Electricity rates, 30% on gas rates for Dual Fuel customers.
Exit fee: €50 per fuel

Taxes and Pass through charges

VAT applies at 13.5%. The Public Service Obligation (PSO) Levy has been set at €.7.40 (inc VAT) per month from 1st of October 2020. This applies to all domestic electricity customers irrespective of supplier. The Carbon Tax has been set at 0.0041995 (inc. VAT) per kWh. This tax applies to all domestic natural gas customers, irrespective of supplier.

graememk · 18-02-2021 08:12PM

slave1 wrote: »

Interesting, I have an EV Charge Point so can switch, currently paying 14.22c day and 6.82c night with 22% Day usage and 78% Night usage...if I was on this plan it would result in a 14% drop in my leccy (usage) costs

I'm currently charging batteries at night and have pv

I'm on about 90% night rate

the_amazing_raisin · 19-02-2021 11:12AM

graememk wrote: »

I'm currently charging batteries at night and have pv

I'm on about 90% night rate

With lockdown we're about 50% night usage, so it's not quite worth it yet with the higher day rate. Going back to normal it'll be closer to 70% and it works out better then

Need to get some batteries to push the night usage up to 90%, saves a few hundered per year then

garo · 19-02-2021 05:19PM

You also lose out on the 35 Euro cashback vs the standard day/night offer. Day rate is 2.42c dearer and night rate is 2.05c cheaper. You'd want to be using at least 75% night rate to make it worth your while.

Today is 1 year since I got a D/N meter and with lockdown (and solar and an EV since September that is not being driven much) my usage has been 2036 D/
2321 N. So not worth it for me.

willbeuptuesday · 24-02-2021 12:51PM

hello everybody,

I'm new to this thread and I am looking for advice, I am about to start renovating my home which was built in 2004. Its a bungalow approx. 2400 sq feet and south facing. I live in the Sunny South east!! I am installing a heat pump and we are a s family of 5 (we would use the standard amount of electricity). So my questions are as follows
1. Is it worth getting Solar PV?
2. I've been told by experts that I can get up to 14 panels on my roof, is this enough?
3. Can somebody give me a ball park figure of what this should cost, Ive gotten various prices for the same products, its like I'm in a western with all the cowboys I'm dealing with!
4. Will the PV panels be able to run my heat pump.
5. Should I look at getting a separate system whereby I can heat my water from solar so I don t have to run the heat pump in the summer.
6. Will I make any money back from selling excess to the grid?
7. Is it worth applying for a grant/

Any help would be appreciated

DrPhilG · 24-02-2021 01:23PM

With regards to the council planning limits, specifically the 50cm gap at top, bottom and sides...

We all know that nobody cares 2 hoots about the planning regs, and they will in likelihood be removed at some point anyway but my question is whether that 50cm requirement is just a typical planning department arbitrary figure, or whether there is any actual logic for it, like it being more prone to wind damage etc?

I'm forward planning. Have a number of possible plans going forward. Increasing battery storage the DIY route is one, but also looking at eventually doubling my panels.

That would result in my garage panels only being about 35cm from the top and the bottom. If we forget about the daft planning situation, is there any good reason not to do this?

air · 24-02-2021 01:27PM

I think the 50cm is fairly sensible in terms of both reducing wind uplift and allowing some sort of roof access for fire fighting or rescue etc if required.
On a garage I wouldn't be too concerned about that aspect though.

It's sensible for maintenance however as ridges, gutters and verges are most likely to require attention and panels would get in the way of this.

KCross · 24-02-2021 01:41PM

willbeuptuesday wrote: »

I'm new to this thread and I am looking for advice, I am about to start renovating my home which was built in 2004. Its a bungalow approx. 2400 sq feet and south facing. I live in the Sunny South east!! I am installing a heat pump and we are a s family of 5 (we would use the standard amount of electricity). So my questions are as follows

Good luck with it.
Are you getting grants for the renovation... heat pump grant etc?
Are you installing underfloor heating, extra insulatation etc?

willbeuptuesday wrote: »

1. Is it worth getting Solar PV?

Depends on what your expectations are.
The payback will be measured in years (likely 10+) depending on what you install.

willbeuptuesday wrote: »

2. I've been told by experts that I can get up to 14 panels on my roof, is this enough?

No right or wrong answer. Put up as many as you can afford and can fit on your roof. If you have multiple roof's facing different directions look to split the install across them so that you can get more generation in the evenings (west facing roof).

willbeuptuesday wrote: »

3. Can somebody give me a ball park figure of what this should cost, Ive gotten various prices for the same products, its like I'm in a western with all the cowboys I'm dealing with!

Yea, lots of cowboys and wild quotes about.
A 14 panel system would be in the order of €4500-€5000 after grant.

willbeuptuesday wrote: »

4. Will the PV panels be able to run my heat pump.

Yes and No. There will be times where it will but in the overall scheme of things it will not run the heat pump much. You heat pump will run alot at night and during the winter when there will be little or no Solar generation.

Dont buy Solar on the basis of it running your heat pump. Buy Solar PV so that you can consume the electricity during the day when its generating electricity. What you dont use you will get paid for via a soon to be agreed Feed-In-tariff (expected Jul 2021).

willbeuptuesday wrote: »

5. Should I look at getting a separate system whereby I can heat my water from solar so I don t have to run the heat pump in the summer.

They call these water diverters. It wont pay for itself in electricity consumption terms as they cost a few hundred to buy and heating water via a heat pump is highly efficient.
However, there is a small case to be made that keeping the heat pump off during the summer prolongs its life but it is a very small case... the heat pump will eventually die anyway and the water diverter will also die so its a tough call.

I'd be leaning towards not having a water diverter and spend the money on more panles instead particularly now that FiT is coming in this year.

willbeuptuesday wrote: »

6. Will I make any money back from selling excess to the grid?

Yes, but small money.... probably <€100 per year.

willbeuptuesday wrote: »

7. Is it worth applying for a grant/

Yes unless you happen to know a roofer and an electrician or are willing to do DIY yourself.

DrPhilG wrote: »

I'm forward planning. Have a number of possible plans going forward. Increasing battery storage the DIY route is one, but also looking at eventually doubling my panels.

Would adding additional batteries make any sense, even a DIY one, with FiT on the way?
You will have to buy a battery. FiT is effectively giving you a free battery overnight and money coming in immediately. You already have everything in place so no additional capital expenditure. Why would you invest more in a battery in that scenario?

Lash up more panels alright though... more the merrier.

DrPhilG · 24-02-2021 02:13PM

KCross wrote: »

Would adding additional batteries make any sense, even a DIY one, with FiT on the way?

You will have to buy a battery. FiT is effectively giving you a free battery overnight and money coming in immediately. You already have everything in place so no additional capital expenditure. Why would you invest more in a battery in that scenario?

Lash up more panels alright though... more the merrier.

I know it probably isn't a financial benefit, more a project that I'd like to do. My friend has already done the hard work, he has a 9kWh battery made from Leaf cells. He is currently upgrading to a 40kWh system and once he's done he's thinking of selling the 9kWh version complete with all connections and a BMS.

For what I could get for my 2 pylontech batteries second hand, I could buy his system without any (or very little) additional outlay. Plus I could then add another 20kWh for just the cost of the battery from a scrapyard plus some DIY to strip and connect.

If I double my panels I'd have 12kwp and going by last year's results I could potentially generate upwards of 70kWh in a day.

That would fill a 30kWh storage, run the house and export the remainder to the grid for a few cents. I could also take the house to 100% night rate with that level of storage.

But as I say, this is as much a fun project as a financial decision.

With regards to the panel expansion, would I be right in thinking that I will have to change the string setup from the current model?

Currently I have the garage panels on one string fed back to the inverter in the house via 100m DC cable, and the house panels on the other string.

The sensible modification would be to double the house panels and the new ones would replace the garage string. Then add another inverter in the garage to connect all 18 garage panels, and the DIY batteries ac coupled if I go that route?

KCross · 24-02-2021 02:21PM

DrPhilG wrote: »

I know it probably isn't a financial benefit, more a project that I'd like to do.

Fair enough.

DrPhilG wrote: »

My friend has already done the hard work, he has a 9kWh battery made from Leaf cells. He is currently upgrading to a 40kWh system and once he's done he's thinking of selling the 9kWh version complete with all connections and a BMS.

For what I could get for my 2 pylontech batteries second hand, I could buy his system without any (or very little) additional outlay. Plus I could then add another 20kWh for just the cost of the battery from a scrapyard plus some DIY to strip and connect.

Wouldnt you have to pay an electrician to install/configure it? As you know they dont come cheap unless you have a spark friend that will do you a twist.

You probably need to buy/change inverters also... more money.

In any case, you are not doing it for financial gain, so have at it!

slave1 · 24-02-2021 02:22PM

DrPhilG wrote: »

If I double my panels I'd have 12kwp and going by last year's results I could potentially generate upwards of 70kWh in a day.

Do it, everything in your full post is dead on, looking at your monthly generations you have great aspect.
After a year or so your next step would be a 6kWp wind turbine and work out the financials of a back-up generator and going off grid.

DrPhilG · 24-02-2021 02:46PM

KCross wrote: »

Wouldnt you have to pay an electrician to install/configure it? As you know they dont come cheap unless you have a spark friend that will do you a twist

My friend who built the 9kWh pack did most of it himself and then had the guy who installed his PV finish it up and test it. So that aspect shouldn't cost too much and I have budgeted for it.

KCross wrote: »

You probably need to buy/change inverters also... more money

Don't think I'd need to change inverter to go to the DIY battery, but I would need an additional inverter if/when I add panels.

slave1 wrote: »

After a year or so your next step would be a 6kWp wind turbine and work out the financials of a back-up generator and going off grid.

I've always wanted to go with wind power due to my location. Strong winds almost year round. But any time I've looked into it the costs are north of €20k. Even if ROI isn't the driving factor, that's just prohibitively expensive.

DrPhilG · 24-02-2021 02:50PM

On a side note, I still haven't wrapped my head around the FiT proposals.

For a house built in 2006, with a B2 BER, 6.2kwp PV installed via grant in July 2020, potentially increasing to 12.5kwp eventually...

What's the bottom line to my pocket?

graememk · 24-02-2021 02:59PM

DrPhilG wrote: »

On a side note, I still haven't wrapped my head around the FiT proposals.

For a house built in 2006, with a B2 BER, 6.2kwp PV installed via grant in July 2020, potentially increasing to 12.5kwp eventually...

What's the bottom line to my pocket?

Well what's proposed,
Just the "clean export guarantee" - average wholesale rate, suppliers have the option of paying more. - that's what you'll get

The premium one is only for installs after the end of June, with ber requirements and caps.

Will need a smart meter and people with the nc6 form in will be priority.

Will be about 5-6c / kwh exported.

air · 24-02-2021 03:00PM

Going off grid makes no financial sense in this country if you already have a connection, the standing charges are negligible, you'd spend as much fueling and servicing a generator for even very occasional use.
Add to that the fact it's far more environmentally friendly to export your inevitable excess energy in summer.

DrPhilG · 24-02-2021 03:07PM

graememk wrote: »

Well what's proposed,
Just the "clean export guarantee" - average wholesale rate, suppliers have the option of paying more. - that's what you'll get.

Perfect, just the summary I was looking for.

Any restrictions on how much you can export? On a single day last year I generated 36kWh plus and exported 18kWh of it.

Obviously if my storage plans go ahead then I'd fare a lot better but also if my expansion happens then I could potentially be looking at generating north of 70kWh in one go. If the battery was still pretty full from the previous day then even running every appliance I have all day long I could be looking at exporting 50kWh.

slave1 · 24-02-2021 03:13PM

DrPhilG wrote: »

Perfect, just the summary I was looking for.

Any restrictions on how much you can export? On a single day last year I generated 36kWh plus and exported 18kWh of it.

Obviously if my storage plans go ahead then I'd fare a lot better but also if my expansion happens then I could potentially be looking at generating north of 70kWh in one go. If the battery was still pretty full from the previous day then even running every appliance I have all day long I could be looking at exporting 50kWh.

Are you not questioning your expansion then, will you end up over producing for 6-8months of the year?
Is that outlay worth it for 4 months of the year when relatively little solar?

mp3guy · 24-02-2021 03:16PM

slave1 wrote: »

Are you not questioning your expansion then, will you end up over producing for 6-8months of the year?
Is that outlay worth it for 4 months of the year when relatively little solar?

Depends how you define worth. Some people here are just plain enthusiasts.

slave1 · 24-02-2021 03:18PM

True, I'm at 7.4kWp and looking at late Spring project to add another ~3kWp but as a two EV household I want to consume and not export

DrPhilG · 24-02-2021 03:36PM

slave1 wrote: »

Are you not questioning your expansion then, will you end up over producing for 6-8months of the year?
Is that outlay worth it for 4 months of the year when relatively little solar?

Worth thinking about, and it depends on the cost to expand.

My best month last year was August (only installed late July). I generated 570kWh, exported 147kWh and bought 300kWh.

So even in my best month I bought 300kWh. With double the panels and additional storage I could essentially be off grid for the month.

I might just do a little calculation now from August's figures, based on bugger storage and rolling export over to the next day to see what it would have looked like if I had double the panels and storage.

KCross · 24-02-2021 03:54PM

DrPhilG wrote: »

Any restrictions on how much you can export? On a single day last year I generated 36kWh plus and exported 18kWh of it.

I dont remember seeing anything about a limit on how much you can get paid for on CEG other than you will be bound by Eirgrid's export limit on the inverter.... 6kW for single phase.

If you double your panels and then have 10kW of excess you are going to lose the 4kW as your inverter will limit the export.

If you can keep the excess <6kW then you can export that and get paid all day long.

Now, thats what the consultation document described... that doesnt mean thats what will be implemented.

DrPhilG · 24-02-2021 04:23PM

KCross wrote: »

If you double your panels and then have 10kW of excess you are going to lose the 4kW as your inverter will limit the export.

If you can keep the excess <6kW then you can export that and get paid all day long.

So that 6kW is the rate of export? So taking my best ever day (August 8th last year), I'd generate 71kWh, start with a near empty battery and generate an average of 8kW average from 12 to 7pm with peaks of 10kW.

If I'm at work, can't plug in the car. But the house would use an average of about 500w (barring running dishwasher etc) leaving 8.5kw to be dealt with. If the export is limited to 6kw then that's 2.5kw remaining, which should be fine for the battery & Eddi to eat up. And I'd export about 42kWh and pocket an awe inspiring €2!

I need to check what the charge rate of my friends DIY battery is. But other than that is my rough math OK or am I missing anything. Obviously on an ongoing basis I would probably be starting the day with a fair bit of juice in the battery but I'm usually at work 9-5 so I'd just charge the car more at home overnight to use it up in advance of a sunny day.

slave1 · 24-02-2021 04:35PM

DrPhilG wrote: »

... so I'd just charge the car more at home overnight to use it up in advance of a sunny day.

Ooooh, charging house batteries via PV to charge an EV later just seems messy.
Totally see where you're coming from but again pointing to over production.

When I put in my third string the plan is near vertical orientation as it should be primarily Winter sun I'm after, if I don't go vertical I will be way overproducing come the good months.

I also see your reference to your best day, I have a feeling your best day is still ahead of you and you'll get it in April/May and not high Summer

KCross · 24-02-2021 04:42PM

DrPhilG wrote: »

So that 6kW is the rate of export?

Yes, same as it is today assuming you have a 6kW inverter?

DrPhilG wrote: »

So taking my best ever day (August 8th last year), I'd generate 71kWh, start with a near empty battery and generate an average of 8kW average from 12 to 7pm with peaks of 10kW.

If I'm at work, can't plug in the car. But the house would use an average of about 500w (barring running dishwasher etc) leaving 8.5kw to be dealt with. If the export is limited to 6kw then that's 2.5kw remaining, which should be fine for the battery & Eddi to eat up. And I'd export about 42kWh and pocket an awe inspiring €2!

I need to check what the charge rate of my friends DIY battery is. But other than that is my rough math OK or am I missing anything.

Rough math looks OK to me other than, of course, it wont work on averages. Your peaks will be higher (12kW) so you will have more losses.

You can mitigate that a bit by splitting it across your two orientations but you also need to match the max voltage on each string so you might run into complications there too.... but your rough math is sorta ok.

The main limitation you will have is the 6kW export limit. Everything else is down to how you configure things internally (EV, Eddi, orientation split, inverter capability etc).

Solar PV Hints, Tips & Troubleshooting

Comments