Is an Eddi worth it for my setup

kavo87

Hi Guys,

Just started looking for quotes: The best one so far:

8 panels 3.2kw (400w panels) South Facing

Solis Inverter - Hybrid - 3.6kwh

My Energi - Hot Water Diverter - My Eddi

BER

Van Der Valk Mounting Equipment

Earth Rod

Shunt

€5770

I don't have an immersion so would have to get one fitted and might need a new element for the hot water tank so no idea yet how much that might cost maybe 2-300 extra. We might be lucky and the element is fine. Currently use the gas to heat the water. Don't use a huge amount of hot water, as we've and electric shower, the bath for the little lad and wash a chopping board or that.

I know it's a convenience having hot water on the go. I'm really in two minds what to do.

If you use an electric shower you probably won't get best use of an eddi. Export it and you get paid.

bullit_dodger

Eddi's make zero financial sense where the night rate is less than your export rate. Better off just heating up the water at 7am for an hour on night rate and any half decent insulated tank will hold onto the heat for 12-18 hrs reasonably well - and then export any surplus you have during the day at the higher rate. So It'll never pay for itself over it's lifetime. I have one, and I'd buy one again for various non-financial reasons, but if your investing in one to save money - that's not a good move.

Outside of that, €5k+ for 3.2Kwp in panels is pricey. Not outrageously pricey as smaller systems tend to be less bang for buck than 6-7Kwp ones, but do make sure to shop around.

slave1

EDDI never makes financial unless not grid tied in which case it will allow smart diversion prior to inverter clipping.

For Grid Tied systems it still makes sense if your cylinder is relatively small as it will heat the water during the day and avoid grid import. It also makes sense to avoid use of electric shower during day/peak rates.

Right now it makes most financial sense to heat at cheaper night rate (if available to you, not available to a lot of folk on Smart Meters) into a large enough highly insulated cylinder that can satisfy hot water demand for the full day, and then export everything.

In fact, right now, it makes no sense to have the likes of a Zappi either for the same reason, off the shelf batteries are also not worth it which means Hybrid inverters are also not worth it.

But, and it's a big but, this is based on current export rates, when these drop (as currently artificially high) and they could drop significantly then the worm will be reversed and we'll all be back looking at EDDI/Zappi/Battery setups

graememk

https://www.boards.ie/discussion/comment/121709505#Comment_121709505

And in off grid, although possible, an eddi doesn't work out of the box as most things are DC when off grid.😂

kavo87

Thanks all for your replies. Think I'll go down the route of not having one installed. Don't think I can justify the extra cost and work needed for one in the house.

Got a 3rd price without an eddi for €4350 for a 3.2kwp.

allinthehead

https://www.boards.ie/discussion/comment/121716748#Comment_121716748

That's a great price, you'll make your money back in 4-5 years.

slave1

https://www.boards.ie/discussion/comment/121725825#Comment_121725825

Not a hope, say an annual generation of 3.2MW and 100% exported (which is impossible as grid tied will go to house load first) at say 20c FIT, then that's €640 pa. 7 years payback but with house load taken into account more like 8 and if FIT halves then good luck on payback..FIT is currently way over the wholesale rate

kavo87

https://www.boards.ie/discussion/comment/121728215#Comment_121728215

Would it not be more along the lines of if I produced 3.2mw and say use half and sold back half would be more realistic. With what I'm paying per unit (39c) and FIT (21c) would bring you a lot close to 4/5 years ROI.

slave1

Then you need to look at your electricity plan and use only electricity at the cheapest rate, certainly not day rate. I used 3 Day rate units last month as my night rate is 14.75c versus (i honestly cant remember) ~36c day rate. So export as much as possible (once FIT higher than your cheapest Grid rate).

As an extreme example I could change my electricity plan to the highest day rate plan out there and consume at high rates which would shorten my payback but I'd be cutting off my nose to spite my face.

EDIT No battery in that quote I am talking to, that seems to be today's route due to current FIT rate, that would alter my stance and the 50/50 consumption/export is a fairer approach alright but I still have my doubts on the long term high FIT rates

slave1

Two years ago we were saying FIT will be crap and get a battery, now we are saying FIT is excellent (which it is) so don't get a battery. But things could change if all the FIT rates plummet to single cent figures, we'd all be back on the battery train again.

I think DIY battery is still the best of both worlds and the safest approach

ColemanY2K

i have the latest model eddi lying in the utility unused. it can't be linked to the cylinder (a long story) but if i decide i need an additional storage tank i'll have it fitted to that.

my point is that like slave said the FIT rate is likely to fall significantly in the coming years and we'll be back to battery train again. at that point eddi's will also be all the rage again.

the good news is the cost of the materials going into batteries is tumbling and forecast to fall even more meaning cheaper batteries when that train starts up again.

allinthehead

https://www.boards.ie/discussion/comment/121728215#Comment_121728215

Taking house load into account shortens the payback time. Plenty of people stuck in contract with daytime rates of 30-40 cent.

bullit_dodger

https://www.boards.ie/discussion/comment/121730913#Comment_121730913

I think that's the key there. If you produce 3.2Mwh of electricity, then you are either going to get paid the FIT rate for a unit of it (currently for me that's €0.24 last time I checked with Energia), or your going to get paid whatever it saves you from importing during the day (€0.38 for me). Loading shifting etc is valid and I still do it myself, but it's sort of a side point.

So the reality that it will be a mix of something between the FIT rate and the day rate. Lets say it's half way at €0.31. So then your looking at €0.31 x 3,200 = €992 a year. Call it a €1k.

Sure, you can pokes holes in that "back of the beer matt math" but ballpark €1k a year in savings. Maybe it's €900, fine.... or call it even €800 as the FIT rate and day rate goes down which we expect over the next year or two......but you'll be quids in anyway after a few years and have done right by the enviornment.

Fantana2

https://www.boards.ie/discussion/comment/121731061#Comment_121731061

This is bang on for houses with solar and no battery, self use at day rate and then FIT for excess.

unkel

https://www.boards.ie/discussion/comment/121730165#Comment_121730165

Exactly this. The game changes all the time and the goal posts move. This time last year I had a day / night meter so wasn't paid for export, so I self consumed all of it. Now I export as much as I can. If I buy 42kWh per day and sell 12kWh, my provider pays me for the day 😂 That's right, I could have a net annual consumption of 11MWh (enough for house, hot water and 2 EVs) and my total annual bill would be zero.

Soon all this could be different again with optional agile tariffs where you know 24h before what the actual rates will be for every 30 minute slot. And they could be wildly negative and positive. You could get paid for consuming electricity or you could have to pay for exporting. Mad stuff! But I'm ready for it.