Contemplating getting solar panels for 4 bed detached house 206 degree SW direction from front window.Is it possible get panels for electricity and sell over flow back to grid Smart meter being fitted shortly My estimated yearly usage is around 3500 kw . It seems any providers I made queries with want to put in batteries , and water heaters etc . Just want to use electricity generated and sell on excess and get payment off bill at the end of payment period. Have gas in the home turn on for an hour for water Some advice would be appreciated
Solar installation query
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fidelcastro
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Its entirely your decision regarding batteries and water diverter /eddi install.
Using gas during summer for DHW is very inefficient, with the eddi your will like have hot water from April to Oct.
3500kWh isn't large usage energy usage, decoupling our lifestyles from world despots was a big reason for my change.
rustbucket
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You do not need to get batteries installed
Yes any excess can be sold back to the grid through your provider once smart meter installed. Micro generation scheme. Most providers have published their buy rates.
Bord Gáis are due to pay mine in feb (payment made once a year)
I would recommend getting a hot water diverter. It’s free hot water as Fidel said from April to Oct.
I would also recommend getting a larger inverter than required that will allow you to add more panels to your system at a later date
We put 8 panels in and now want to put in more but need a larger inverter to add to our system. Otherwise it’s a whole separate 2nd system install
Also potentially think about wiring for a car charger. You may not have an EV but it could be a possibility down the line and they can do that at the same time and you can install chargers at a later date
Yes any excess can be sold back to the grid through your provider once smart meter installed. Micro generation scheme. Most providers have published their buy rates.
Bord Gáis are due to pay mine in feb (payment made once a year)
I would recommend getting a hot water diverter. It’s free hot water as Fidel said from April to Oct.
I would also recommend getting a larger inverter than required that will allow you to add more panels to your system at a later date
We put 8 panels in and now want to put in more but need a larger inverter to add to our system. Otherwise it’s a whole separate 2nd system install
Also potentially think about wiring for a car charger. You may not have an EV but it could be a possibility down the line and they can do that at the same time and you can install chargers at a later date
Scoobydoobydoo
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Best check out the renewable section on boards, very active/knowledgeable folk along with recent quotes.
Might be beneficial to defer the installation of your smart meter. A day/night meter is what they are all after. Once you are on a smart meter you cant revert back.
www.boards.ie
Might be beneficial to defer the installation of your smart meter. A day/night meter is what they are all after. Once you are on a smart meter you cant revert back.
Renewable Energies
Sustainable and renewable energies such as Solar Panels Geothermal Heating and Wood Pellet Boilers etc
www.boards.ie
I think the economics of the eddi vs gas are marginal. €500 to purchase + install. That's alot of surplus kWh to be generated before system inefficiencies; Tank capacity, destratification pump, if your central heating system heats the water tank while CH is on etc.
rustbucket
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Agreed. But having the ch on just to heat water from April to Oct is surely not very efficient
I never turn mine I just for water but if it’s on for heating absolutely it’s on for water also
David_Dublin
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I've never heard that one before - surely most systems don't require CH to be running to heat HW?
Wouldn't you need to use gas or something else to heat the HW when the sun isn't shining and HW runs out?
Using the boiler won't be as efficient as electricity which is close to 100% efficient, but the price differential means using the boiler will be significantly cheaper.
I presume they mean running the central heating boiler to just heat the water. Most modern central heating installs will include a separate circuit for the water.
rustbucket
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fidelcastro
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Indeed, but note the Eddi is useful for Apr-Oct use, when its unlikely will have boiler on for space heating reasons, running a 24kW boiler to heat a cylinder of water indirectly is wasteful, if that is your setup. Different if your boiler provides hot water without heating a cylinder of course.
Economics perhaps, but weaning ourselves off Putin, Qatar, Al Saud et al is one input to my reasoning, but if that isnt on yours carry on as normal, dont moan about their influence of their power over your life..
Re :inverter, 6kW is the largest you are allowed by ESB Networks , as explained by Leo previously.
fidelcastro
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Hi Leo, I appreciate your thoughts on this.
Any idea on the efficiency of the "traditional" indirect method of heating a standard sized DHW cylinder, when spacing heating zones are turned off e.g. summer.
New Worchester Bosch condensing boiler, 90% efficient,
but what is an estimate of the indirect heating efficiency, at cylinder, with c.40m of piping (supply and return)?
Prior to PV Eddi, we would have a DHW zoned water heating requirement for c.1hr each day during summer. (4 adults).
24kW boiler, =>24kWh energy @0.1E/kWh = 2.40 euro per day (includes 26% discount, 2023 prices)..
Eddi instal, if 500Euro, => 500E/2.4E= 208days , =>c. 2 seasons of sole usage.
With PV , Gas bills were 11Euro per 2months, (gas stove cooking) , drastically in kWh usage from prior years.
F.
Hard to know for sure, losses in the pippework will very depending on whether it's insulated, in contact with other conducting materials, etc.. Given costs for electricity per KWh of energy delivered is about 3 times that for gas, you could lose most of the heat and still have it work out cheaper to use the boiler.
Just FYI you don't necessarily need to have a larger/second inverter. It is not uncommon to over-size solar arrays to the size of the inverter, the inverter will simply 'clip' any power generated in excess of its capacity. Realistically in Ireland you only get peak production from your panels for a few hours a year, for all the rest of the time the inverter is underutilised.
Oversizing solar inverters - is it a good idea?
Learn about inverter oversizing and how it can impact your solar yields, and reduce your energy costs too!If you’ve been in the market for solar, you’ve prob...
www.youtube.com
Wasteful how exactly? A modern heated hot water cylinder will have only a small thermal loss and thus be a store of energy, like a battery.
I don't think anyone is "moaning", neither do we import Russian, Qatari or Saudi natural gas.
Not quite. 500/0.1 = 5000 kWh. 2 seasons implies that your 8 panel set up is producing a surplus of 5000/2 = 2500 kWh per year?
The eddi uses SURPLUS electricity after your domestic needs. My 8 panel set up produces a SURPLUS of 1200 units per year, for example. Also, the price of a kWh sold back to the grid is ~0.2c. The cost of gas is ~0.1c. If your boiler is 50% efficient, you breakeven.
rustbucket
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Thanks for that. Very useful. Il look up the specs of what I have exactly and get back to my supplier. They may not want to oversized but if it can be done then why not.Just FYI you don't necessarily need to have a larger/second inverter. It is not uncommon to over-size solar arrays to the size of the inverter, the inverter will simply 'clip' any power generated in excess of its capacity. Realistically in Ireland you only get peak production from your panels for a few hours a year, for all the rest of the time the inverter is underutilised.
Oversizing solar inverters - is it a good idea?
Learn about inverter oversizing and how it can impact your solar yields, and reduce your energy costs too!If you’ve been in the market for solar, you’ve prob...
fidelcastro
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Hi Itchy
Fair points, keep your hair on.
The moaning wasnt directed at you,just in general. Note that c.70% some of our gas does indeed come or is influenced by the despots of Putin, Saudi and Qatar, simply because our gas is piped in from Britain , which itself imports Gas from Norge and Qatar and US and a small amount from Netherlands. I wish to minimise my exposure to these countries , aside from Norge.
Price of Gas/Oil is linked, and dictated by OPEC, it is them who set the price.. Anyway, thats enough ranting.
Howandever..
Re:Wasteful how exactly? A modern heated hot water cylinder will have only a small thermal loss and thus be a store of energy, like a battery.
The cyclinder perhaps, but how much X kWh of gas do you consume to heat 1 cylinder full. From my experience, 1hr heating/day in summer for a zoned system, I would not consider excessive for 4 adults. => 24kW boiler =24kWh*0.1E=2.40E/day
Last summer, gas bill was 11kWh per 2month period, with PV , battery/eddi, much less than 2.40E*60=144E.
I have 18 panels, so its not a problem to have 2500kWh excess/annum, produce consistently 20 to 30kWh and close to 40kWh elec per day Apr to Oct.
Aditionally Elec Irelan paid me 190Euro (0.21/kWh) for c.900kWh of export, even taking into account priority is - house, battery, then eddi ,and then export. .
@OP everything in your post is doable, I have however found that solar PV installer prices have gone through the roof, +300% in just over 24 months in some cases. It's hard now to find competitive prices.
To me an Eddie / diverter does not make any sense and I think in most cases you will never recoup what you spend on them.
To me an Eddie / diverter does not make any sense and I think in most cases you will never recoup what you spend on them.
- They cost an extra €500 or so to incldue in your installation,
- They only use electricity that you don't use and would otherwise send back to the grid and be paid around 18-20c for in feed in tarrif.
- Every unit of hot water heating the eddie provides is only saving you one unit off your gas bill so savings are minimal. E.g. saving a unit of gas at 15c when if you had no eddie you would have received FIT payment for that unit instead of 18-20c.
- They don't last long term and seem to all need replacing before ten years.
Well with a setup like that, I can see why a discussion on the economics of an eddi can sound like moaning
Interesting data there but I wonder how accurate is your calc especially with the ability of gas boiler to modulate down their output depending, so while the gas boiler was 'on' for 1 hour a day, what is burning gas at full tilt for the hour?
We have only ever used our conventional oil boiler (system efficiency ~75%) to supply the domestic household hot water needs (there is an electrical immersion element installed but no idea if it works as we have never turned it on!) and I have monitored the oil consumption over several previous years before the kids flew the nest. Household of 5 then (3 teenage daughters at the time). Our heating system is zoned so can separately heat the hw tank without the ch being 'on'. So for the period generally between April and mid to late October (when the ch if off), the oil burner would burn oil for 24 minutes daily (averaged over the period) with a burner rate of 2.6 litres/hr. This equates roughly to 1 litre of oil for our daily hot water needs. The last fill of oil cost €1.1 / litre so even at this elevated price, our cost for hot water would be just over a euro today (much less when we were paying 60c a litre). With the nest almost empty, the hot water usage has mostly halved now.
There is another consideration to regularly running the boiler system over the warmer months. The system is coming up to nearly 20 years old with the normal wear and tear you would expect from a mechanical system. By running the system daily, you are ensuring that any moving parts etc keep moving and don't seize up, something which can become more problematic as the system ages and is left idle over a prolonged period of time.