PV Solar - Battery or not?

[Leo]

If so, would my potential increased upload capacity be in the region of 25% more than the standard connection, or is that too simplistic?

No, it's as simple as that really, though a 16kVA line will support 33% more than a 12kVA one.

Whether that would make financial sense will depend on the tariffs available. I suspect that the buy-back element of small scale setups like this won't justify the investment on their own until the kits come down a lot in price, the savings on your own usage will be key.

 

[Marsupial]

No, it's as simple as that really, though a 16kVA line will support 33% more than a 12kVA one.

oh dear. Embarrassing maths! Thanks for that.

 

[Zenith63]

If it's the feed-in tariffs that interest you, the capacity of the inbound connection will limit output. The standard domestic supply is 12kVA here.

Worth noting that the ESB have a 6kW output limit for microgeneration (or 11kW if you're on 3-phase). You can put up more panels but the inverter would need to be 6kW or less. Not sure what is involved in overcoming that 6kW limit or whether it will always be in-place, but it's also what the ESB used for their feed-in-tariff pilot so I'd say it could be sticking around.

 

[Leo]

Not sure what is involved in overcoming that 6kW limit or whether it will always be in-place, but it's also what the ESB used for their feed-in-tariff pilot so I'd say it could be sticking around.

Just a guess, but it may be to prevent a concentration of large deployments overwhelming the local infrastructure.

 

[Maesus114]

I've since got a few more quotes and it does seem that it's hardly worth putting in a battery when there will be a feed in tariff next year.
I'm still finding it hard to get decent quotes, though, using the €1k per kw. Closest is a company that quote a monthly cost over 10 years but ideally I'd prefer to pay upfront when the money is making nothing in the bank.

 

[Zenith63]

FWIW I had good experience with NextGenPower if you want to try them. They were reasonably priced after a bit of haggling and there was no hard sell from them, just honest advice. I’d use them again if I moved.

I have no affiliation with them whatsoever.

 

[silverfox239]

Interesting maths assessment of batteries....

Home Batteries Now Make A Lot Of Financial Sense!

With the energy prices skyrocketing, the 'payback' period of a home battery (without Solar) makes a lot of financial sense at the moment.Website: www.ev-man....

www.youtube.com

 

[Alkers86]

Interesting maths assessment of batteries....

Home Batteries Now Make A Lot Of Financial Sense!

With the energy prices skyrocketing, the 'payback' period of a home battery (without Solar) makes a lot of financial sense at the moment.Website: www.ev-man....

www.youtube.com

That's specific to the UK. But also, until the details of the FIT are known his maths could be compeltely relevent or completely irrelevant. It's too much of an unknown at the moment.

 

[silverfox239]

Nothing to do with FIT (Feed In Tariffs) or anything specific to UK.

Just basic maths that you charge the battery at a low rate (usually night time rate) and use the battery to Power your house during the day instead of paying the top rate.

So if you have a SmartMeter in Ireland you can avail of the rates below for example.

Switch to our best electricity and gas price plan | Electric Ireland

Find the cheapest gas and electricity price plan for you and switch to Electric Ireland today.

www.electricireland.ie

Electricity unit price
Day: 08.00 - 23.00	24.44c per kWh
Night: 23.00 - 08.00	12.58c per kWh
Night Boost: 02.00 - 04.00	6.79c per kWh
Gas unit price	5.769c per kWh

 

[Leo]

Interesting maths assessment of batteries....

Home Batteries Now Make A Lot Of Financial Sense!

With the energy prices skyrocketing, the 'payback' period of a home battery (without Solar) makes a lot of financial sense at the moment.Website: www.ev-man....

www.youtube.com

Quite a few issues there ...

• Based on UK price plans with night rates of between ~7% and ~25% of the day rate. Very different story here where they are about 50%.
• Assumes that battery storage systems are 100% efficient over charge and discharge cycles.
• Ignores increased standing charge for night rate meter.
• Ignores that day unit costs are more expensive
• Requires moving 16% of consumption to off-peak hours
• He states energy prices won't ever drop back down and suggests they will keep rising ahead of inflation rates while also stating the night rate will forever stay at 5p??? But we already know oil and gas prices are dropping at the moment.

Just rerunning his numbers on a 20p day rate and assuming a night rate of 10p as you'd have here, savings drop to £168 a year. Then take £60 off that for the increased standing charge, increase the day rate in line with what we see on typical day/night plans here and then you're under £150. Start to account for losses in the charge/ discharge and you're looking at a system that would need to last more than 40 years with no additional costs to break even.

 

[silverfox239]

@Leo I think you have some out of date info. to base your calcs on

• Smart meters are rolling out across Ireland at no direct charge to customer. https://www.esbnetworks.ie/existing-connections/meters-and-readings/smart-meter-upgrade
• So no need for night rate meter & therefore extra standing charge so get the reduced night rates
• Ireland does have night rates roughly similar to the UK, see the table above from Electric Ireland

My key point is on a lot of the threads, batteries get bashed as being expensive & nice to have. But given SmartMeter rollout I think people should re-run the numbers.

FIT will help a little but just in Budget 2022 there is a €200 tax relief for money earned from FIT. Anything over that and your taxed at marginal rates, so prob. around 50% tax mark for a lot of people considering this option. So when you play that into the numbers there is an argument to get a battery as better to keep most of the power for yourself and not get taxed on it.

Finally how many people this week (Storm Barra) would have liked to have a battery when they lost power.

 

[Leo]

Smart meters are rolling out across Ireland at no direct charge to customer.

I was commenting on the video as presented, it makes no reference to smart metering.

So no need for night rate meter & therefore extra standing charge so get the reduced night rates

True, but the peak rates are also more expensive than on a standard tariff and the off-peak rate is significantly more expensive than night rate electricity.

Ireland does have night rates roughly similar to the UK, see the table above from Electric Ireland

Who in Ireland provides night rate electricity at a discount of 75% or more? His numbers are based on 75 to 86% discount.

My key point is on a lot of the threads, batteries get bashed as being expensive & nice to have. But given SmartMeter rollout I think people should re-run the numbers.

FIT will help a little but just in Budget 2022 there is a €200 tax relief for money earned from FIT.

Absolutely people need to run the numbers, but they need to run real life numbers that are relevant to the Irish market. Batteries absolutely are expensive, and for many people, they simply will not repay the investment within their lifespan, and that money would provide more value if invested in other energy saving measures. As battery technology improves, that will evolve, but there are very good reasons why these are not popping up on every new build or refurb.

Also beware that feed in tariffs are on the way, there is every chance they will be phased out in the future. That's already happening in other markets due to local congestion issues in the low voltage grid brought about by the success of incentives for domestic PV.

 

[Alkers86]

Quite a few issues there ...

• Based on UK price plans with night rates of between ~7% and ~25% of the day rate. Very different story here where they are about 50%.
• Assumes that battery storage systems are 100% efficient over charge and discharge cycles.
• Ignores increased standing charge for night rate meter.
• Ignores that day unit costs are more expensive
• Requires moving 16% of consumption to off-peak hours
• He states energy prices won't ever drop back down and suggests they will keep rising ahead of inflation rates while also stating the night rate will forever stay at 5p??? But we already know oil and gas prices are dropping at the moment.

Just rerunning his numbers on a 20p day rate and assuming a night rate of 10p as you'd have here, savings drop to £168 a year. Then take £60 off that for the increased standing charge, increase the day rate in line with what we see on typical day/night plans here and then you're under £150. Start to account for losses in the charge/ discharge and you're looking at a system that would need to last more than 40 years with no additional costs to break even.

Exactly!

Also, the gaurantess on these batteries are typically 5,000 - 10,000 cycles. So a 5kWhr battery will only be gauranteed to last 25,000 - 50,000 units worth of electricity. That might sound like a lot but with an average price of 20c per unit that's only €5k to €10k worth of electricity when these batteries are often in the €5k ballpark price themselves.

 

[Leo]

Exactly!

Also, the gaurantess on these batteries are typically 5,000 - 10,000 cycles. So a 5kWhr battery will only be gauranteed to last 25,000 - 50,000 units worth of electricity. That might sound like a lot but with an average price of 20c per unit that's only €5k to €10k worth of electricity when these batteries are often in the €5k ballpark price themselves.

Yep, with the amount of investment going into battery development at the moment I think these might start to make sense in a few years when the cost/capacity ratio and lifespan improve, but it doesn't make much sense now.