New solar PV and battery grant launched today

Zenith63

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The Department of Communications, Climate Action and Environment launched a new scheme to support consumer electricity micro-generation (solar PV) and storage (battery) today!

Administered by the SEAI, it allows for support of up to €3800 to install a solar PV and battery storage system in homes built before 2011.

Basically €700 per kW of panels up to 4kW, but if you go over 2kW you must install a battery storage solution (€1000 allowed toward this) to get the full grant. So a 4kW PV system with battery storage would get the full grant of €3800.

More info: https://www.dccae.gov.ie/en-ie/news-and-media/press-releases/Pages/Minister-Denis-Naughten-launches-pilot-Micro-Generation-scheme-targeting-domestic-customers-and-self-consumption--and-annou.aspx

https://www.seai.ie/grants/home-grants/solar-pv/
 

Susie2017

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Ok can you explain how large this battery is and where it would be situated. How would the power stored in it be used - eg could it feed into the meter and so cut electricity cost further. Would it be worth getting in an Irish climate ? If the grant is 3800 then the installation cost must be huge ?
 

Zenith63

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Yes the idea is that the solar panels would charge the battery during the day, when you’re often not home and not using much electricity but the sun is at it’s max, then you use the power stored in the battery in the evening/night. In theory you should end up using much more of the solar power you generate.

Size wise the likes of the Tesla PowerWall is similar size to maybe a thick 50” TV, you’d often mount it flat to the wall outside.

Cost wise, I’m afraid I’m not sure sorry, my guess is €10k for the battery. Hard to say if it would pay off. If you factor the ‘saving the environment’ value into your calculations that will certainly help :).
 

Laughahalla

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Most people (if they decide on a battery) will probably go for a 4.8kw battery. Can be got cheaper but a decent battery this size will cost about 2.5k to 3k installed(includes VAT) minus 1k from the grant.

For a 4kw solar PV system with a 4.8kwh battery will cost approx 7k after grant of 3.8k is factored in. You will also be able to claim back some of the VAT on this.

Battery can be stored in your attic or utility - You'd need to discuss that with your installer. (Must be SEAI approved for solar PV)
 

cremeegg

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Most people will probably go for a 4.8kw battery. Can be got cheaper but a decent battery this size will cost about 2.5k to 3k installed minus 1k from the grant.

For a 4kw solar PV system with a 4.8kwh battery will cost approx 7k after grant of 3.8k is factored in.
Excellent post laughahalla. So a 4kW PV system with battery costs approx €9k after the grant.

At 16 cent a kW Hr that requires 11,842 hours of operation at 100% efficiency, to break even.

Any idea what the average achieved efficiency might be.
 

Zenith63

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I've been wondering about the average efficiency as well. Out of interest, below is the average power usage per hour of the day of our home for July. This is with two electric cars, quite a bit of home working, gas for cooking rings, space heating and water heating.

Taking a complete stab in the dark, I'd guess a 4kW panel system would cover our usage from 9am to maybe 4pm (so 6kWh out of the total 16kWh used). A 4.8kWh battery would be too small to cover the remaining 10kWh, but with it we'd end up with 67.5% self-generated power. At 17c per kWh we'd be saving about €716 per year on electricity, for a payback in 9.7 years based on the €7k figure mentioned above.

If we went with a Tesla Powerwall (which stores 13.5kWh) the cost for the system (based on figures above, which look very cheap to me tbh) would be somewhere around €11k and we could potentially hit 100% utilisation, which would mean a payback of 10.5 years.

Loads of assumptions in here for sure, but just an interesting exercise. It also doesn't factor in the value of being better for the environment...

One concern with these payback figures of 10ish years is that I'd imagine the lifetime of these battery systems is around 10 years...

Code:
HOUR     kWh
00:00    0.35
01:00    0.22
02:00    0.31
03:00    0.24
04:00    0.19
05:00    0.20
06:00    0.30
07:00    0.28
08:00    0.43
09:00    0.49
10:00    0.53
11:00    0.65
12:00    0.57
13:00    0.85
14:00    1.17
15:00    0.96
16:00    0.98
17:00    1.22
18:00    1.74
19:00    1.38
20:00    0.96
21:00    0.94
22:00    0.93
23:00    0.87
 
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fidelcastro

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If householders could sell their excess PV electricity for a reasonable kWh price REFIT level this would do away with the need for a battery
Unfortunately ESB doesn't allow this, hence driving up the costs with a battery.
Also does anybody wonder about the green credentials of using precious metals eg Lithium, for the type of battery required.

Once again the government is a bit backward compared to international best practice to make this scheme attractive for householders
 

Zenith63

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If householders could sell their excess PV electricity for a reasonable kWh price REFIT level this would do away with the need for a battery
Unfortunately ESB doesn't allow this, hence driving up the costs with a battery.
To be fair, I don't think this is an accident. Large numbers of un-managed home solar generators pose real challenges for the grid that structuring the grant this way and trying to force people to also install a battery somewhat mitigates (interesting article here if interested - http://theconversation.com/why-rooftop-solar-is-disruptive-to-utilities-and-the-grid-39032).

Once again the government is a bit backward compared to international best practice to make this scheme attractive for householders
Again I don't think this is an accident or backward. A recent DCCAE whitepaper (https://www.dccae.gov.ie/documents/Energy White Paper - Dec 2015.pdf) determined that spending money on micro-scale home solar is, by a fairly significant margin, the most expensive way of the government reducing carbon emissions and bringing the country to a greener place. The same amount of money spent on large-scale centralised solar and wind generation would yield much better environmental results while also being much more manageable and predictable for the grid.

So I think best practice would actually be not to bother with these home generation grants, or make them only attractive to people who REALLY want to do self generation (which is what they've ended up with here I think), and pump that money into supporting PPPs to rapidly build solar farms, wind farms and grid-scale storage. We haven't been to great at this in the past, but it does look like a load of solar farms are about to kick off finally!
 

Zenith63

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Goggle thinks the typical efficiency is about 20%. Which would push the payback out to more like 50 years
That’s referring to the efficiency of the panels, showing how much of the energy hitting the panel it will convert to electricity. A “4kW system” already accounts for this though and would create 4kW of electricity, it would just be smaller (area wise) if the efficiency was better than 20%. This efficiency figure doesn't really mean much if you're looking to put a few panels on a large roof, but it would if you wanted to put the highest generating panel you could on top of a car, or a Mars rover etc.
 
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cremeegg

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A “4kW system” already accounts for this though and would create 4kW of electricity, it would just be smaller (area wise) if the efficiency was better than 20%.
Well sort of.

The performance of PV modules and arrays are generally rated according to their maximum DC power output (watts) under Standard Test Conditions (STC). Standard Test Conditions are defined by a module (cell) operating temperature of 25o C (77o F), and incident solar irradiance level of 1000 W/m2 and under Air Mass 1.5 spectral distribution. Since these conditions are not always typical of how PV modules and arrays operate in the field, actual performance is usually 85 to 90 percent of the STC rating. https://www.researchgate.net/publication/224734489_What_is_an_air_mass_15_spectrum_solar_cell_performancecalculations

Air mass 1.5 Spectral distribution, means among other things, cloud cover. The actual performance refers to conditions in Florida. Fingal I'm not so sure.
 

Setanta12

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I'm a luddite here re this - but aren't there two types of solar-panelling; one with tubes of some kind that doesn't care whether you're from rain-swept Wesht of Ireland or sunny Florida ...

And the payback is estimated at 13 years in the SEAI's own literature .. .. ... hmmmm .. .. not. good.
 

Zenith63

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Sorry cremeegg, I thought when you were referring to efficiency in your first post, you meant how much of your generated solar you’ll actually use as opposed to export to the grid...
 

cremeegg

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I'm a luddite here re this - but aren't there two types of solar-panelling; one with tubes of some kind that doesn't care whether you're from rain-swept Wesht of Ireland or sunny Florida ....
This thread is talking about photo voltaic cells, which make electricity. They work off sunlight and actually operate better in low temperatures. These are relatively new to Ireland.

The other type of solar panels work off the heat in the air so direct sun light is not so important. They heat water rather than generate electricity. These have been in Ireland for a while.
 

cremeegg

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Sorry cremeegg, I thought when you were referring to efficiency in your first post, you meant how much of your generated solar you’ll actually use as opposed to export to the grid...
I think you were correct. A 4kWhr PV cell is a cell that outputs 4kWhr under standard conditions. At 20% efficiency it would require 20kWhr of energy from the sun.

However, Since these (standard) conditions are not always typical of how PV modules and arrays operate in the field, actual performance is usually 85 to 90 percent of the STC rating.

And thats in Florida, I would wonder about actual performance in an Irish field.
 

Leo

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Pretty detailed KPMG report on the potential of PV in Ireland here, but note that all the calculations that show domestic PV becoming viable here are based upon the assumption that grid export tariffs will be introduced, and I'm not aware of any proposals for such a move.
 

Leo

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And the payback is estimated at 13 years in the SEAI's own literature .. .. ... hmmmm .. .. not. good.
They have a calculator on the site that lets you input your location, demand, usage patterns etc. to get a more accurate calculation. Mine came in at 17 years, and that excludes any ongoing maintenance costs.
 

shweeney

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SEAI: On average, a solar PV system can save between €200-€300 per year on your domestic electricity bill

If the system costs 9K to install, that's a 30 year payback period. No thanks.
 
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