Domestic Solar PV installs - grant stats

Mad and not a single one measured the system to see if it was viable.

It doesn't for two reasons. The installers are pocketing the subsidy and the payback/network enhancement would be better without battery coupling.

Have you measured your round trip efficiency yet Unkel? Please do. Data is truth.

It's academic Unkel and a figure we ought to be discusing because it'll expose the sham for what it is. I can only speak for my hardware and I currently have 4 systems that are similar to what's being flogged as the solution to no FITs on the basis that all the calcs are founded on contrived marketing figures and not real world applications.

From what I've documented lead acid & li-ion are about 95 - 99% efficient. Chargers are about 75% to 85% efficient and inverters are 60% to 95% efficient. In the real world where we use these systems. This is a best case with ideal loads, there are many many derating factors to be accounted for in day to day use.

My best performing system according to the testing I have done is ironically lead acid and it's 60% round trip. If I lost the battery and charger solar input would be ~90% power on the network.
All the added expense of battery, switchgear, installation etc is not going to be met within the lifetime of the system if I was buying power at €0.16 per kwh and selling it to myself for €0.26 per kWh.

If I coupled my solar to a battery I would turn my 2.5kW array into effectively a 1.5kW array and pay an extra maybe €3k for the service of using it at night.

What people are advising with battery coupling is extending payback time, reducing system performance and increasing upfront costs. There's nothing green about it.

If the system is too big to meet the user demands then get a smaller system instead of throwing hardware losses at it until there's nothing significant left except warm electronic devices.

I say it over and over again. If the cost of the battery was put into just solar there'd be double the power on the network with 30% less losses at the source.

How can anyone say that a system is working if they don't measure it? What's that based on? What the person selling it said? Or they read on a forum that was unfounded?

I am using decade old proven hardware that's the parent and inspiration of these newfangled whizzbang boxes that sprouted like mushroom fields.
I'm highly curious that they're any better and would love to see some evidence. So far I have not and I'm on the tools every day, granted I only work on systems where utility is at best not permanent or my own house.

People giving advise about things they haven't measured or documented holds no water.
As far as I'm concerned people are paying in the order of €4k over the odds to keep 60% of what the could have produced with SEAI approved battery coupled systems. ...after the grant is applied.

If a datasheet says 95% efficient more often than not; real world it is 80%.

kWh counter out / kWh counter in x 100 = round trip efficiency. The best eye opening €50 you can spend.

Can you tell me what the measured empirical payback time financially and in terms of net usable energy of such an example system is compared to a batteryless system?
Or is that a trivial detail?

And what is the import offset value of the battery system per annum?

So the battery cost? Roughly €1k?

Battery payback 6 years? Not including the inverter to use it or install. Life expectancy 10 years.

€1k of solar instead = 1000Wp producing ~€200 per year (if used as offset)
minus losses in 4.8kW battery coupled system having removed said battery = ~3MWh offsetting fossil fuel energy producion on the network.

I'm not saying a FIT would be better. I'm saying the battery is an expensive efficiency reduction device.

The power to make the battery came from the grid...and will only be returned by end of life.
Solar return is being retarded by having to finance the battery as well as itself.

I can get a lead acid 2.4kWh battery for ~€300

I know the amount of times I ask users to measure their system to quantifiably validate it's merits to share with the rest of us and the outcome is...

I guess it's an unimportant detail to comparatively measure energy production of a generation system.

I'm not having a go Garo. There's no real world data on the comparative viablilty of these systems. It is the first thing I would ask for. I'm trying to get more people to ask the same question. I have measured all of mine and the answer is always not competitive with utility (unlike just solar).

Would anyone like to buy this ambiguous amount of petro-chemicals from me?
Does that sound absurd? €2k to you + €1k from the government.

This solar battery thing is all too similar to buying a wind turbine before the anemometer.

Apologies if my manner is abrasive...I'm a cynic because I measure against manufacturer claims.

The power isn't free if you buy a battery and extend the solar payback substantially to be reimbursed for it.

I agree and I don't believe any current chemical battery charge/discharge topographies can cut it.

I fixate on efficiency? Yes.

Can you swap me a score for 3 fivers?

Thanks Garo but yer alright I have my own 4 year payback orchard working great in the Summer and in the Winter the utility network is quite reasonable compared to Apple carts.