The Lemon Fool

Has anyone here added battery storage to their solar panels ?

With the recent increase in electric prices Im considering it , been quoted around £3.5k for a battery storage system but as usual theres a few types to consider.

Some people have suggested one that charges the batterys from solar in daytime and from a cheap eco 7 tarriff overnight , some a system that charges batterys straight off the panels , others that allow my inverter to convert the power to AC , then use another inverter to convert it back to DC for storage

other thing is Im not sure how much spare electric we actualy send back to the grid . Parents have got a smart meter that shows when power is going back to the grid , but not how much is actualy been exported - had considered seeing if i could get an export meter fitted for my own info if it was a cheap option to see how much I actualy send back

The more I read , the more I become confused

On the other side as far as the solar is concerned I see Decembers RPI was 7.5% so thats the increase we get on the FIT from April , so now over 60p per unit that I generate

I looked at this a year or so ago, the batteries were around £5K and concluded that it wasn't going to be cost effective. We live in Essex where we generate a lot of solar energy in the summer months but hardly enough to run the house in winter, let alone heat water or provide battery storage. My calculations showed at least 10 years to break even. I'm waiting until the price of batteries comes down.

like almost everything else on the renewables front, not economic without subsidies. I calculated 23 years for break even, not trying to allow for inflation.

The most advantageous 'battery' is if you have an old analogue meter that runs backwards when your panels output more than your home is using.

You are under no obligation to notify anyone of this, which is curious!

https://smarthomeenergy.co.uk/electrici ... backwards/

steelman99 wrote:
other thing is Im not sure how much spare electric we actualy send back to the grid . Parents have got a smart meter that shows when power is going back to the grid , but not how much is actualy been exported - had considered seeing if i could get an export meter fitted for my own info if it was a cheap option to see how much I actualy send back

If you have a smart meter, then you should be able to get readings for both imported and exported power. If you google your meter model you will find instructions on how to do this.

If you have an old analogue meter, and the old FIT scheme, I am afraid I can't help you.

FD

Just as an off-the-wall alternative, have you looked at these: https://lavo.com.au/#prime ?

This is an Australian company who have a box which stores solar generated electricity as hydrogen.

I, personally, think this may be a good way forward. Store excess solar electricity as hydrogen, which can then be used for cooking, heating, or converted back to electricity when the sun doesn't shine. You may even be able to power your car with it.

I am told that Lavo have an order book of at least 18 months, but I wonder if others will follow suit.

Bminusrob wrote:This is an Australian company who have a box which stores solar generated electricity as hydrogen.

I, personally, think this may be a good way forward.

The trouble with this, as with everything to do with hydrogen, is it's massively less efficient than staying electric, in this case you lose 50% of your energy on a round trip from electricity - hydrogen - electricity so it's only worth it if you've got so much solar energy you can afford to waste it. Which may be the case in the Outback, but is unlikely to be the case in Oldham.

Question would probably be better asked on the DIY board, as they've got more experience of the practical side of things.

More like 30% at present, with 45% perhaps possible with technology being developed and used at industrial, not home scale. https://www.greentechmedia.com/articles ... aring-hype. The only way to improve on these numbers is to use the waste heat for space heating.

I was merely going on what Lavo claim in FAQ#11 :
https://lavo.com.au/faq/

I have no particular knowledge of their system, but as a university spinout they may well be doing something a bit cleverer than the market average, whilst still not able to overcome the laws of physics and make hydrogen round-trips somehow anywhere near as efficient as batteries.

JohnB wrote:More like 30% at present, with 45% perhaps possible with technology being developed and used at industrial, not home scale. https://www.greentechmedia.com/articles ... aring-hype. The only way to improve on these numbers is to use the waste heat for space heating.

But 30% is the round trip electric-hydrogen-electric. BminusRob was suggesting spare electric to hydrogen and then burn the hydrogen for direct heat. Which I would suspect is MUCH more efficient. From my knowledge of physics/chemistry, I would have thought electric to hydrogen is fairly efficient, it’s the hydrogen back to electricity where most of the losses occur (yes??)

Gryff

A number of years ago ITM Power were showing a picture of a Pump like unit the implication being that they could be sighted at the side of a house all it needed was water and electricity. So a good solar supply or cheap overnight electyric could make Hydrogen that could be used for anything. So far no more has been heard of this. They soaked up millions on development which now appears to be coming to fruition.

Bob

I have solar panels that produce around 3700kWh per year. I use about 3000kWh of electricity in the home in total per year.

I don't have a battery, but I do have an electric car, which needs about 2000kWh per year to fuel the 8000miles I drive.

I have an EV tariff with Octopus which offers me 4 hours of electricity at night at 5p per kWh (and 15p per kWh during other hours). With this I can charge the car and run a few appliances overnight (eg dishwasher, washer, bread maker). I have an export tariff (SEG) of 4p per kWh with OVO, as I cannot use much of the solar produced in the summer months. So for the solar power I export in the summer, I can get it back at night for a net 1p per kWh all the year round.

I don't think I can do much better on electricity. That might all change when the tariffs and SEG rates change later this year!

For gas, I use 15000kWh for heating and hot water. I would need to increase my solar panels by x5 to cover this - impractical, even with masses more insulation. If I could I would consider a battery, but I can't.

I think I will need to use the grid for heating and hot water for the foreseeable future!.

FD

The other option is that AFAIAA you can get a device that turns on your hot water tank immersion heater when you have surplus solar energy so that it gets used to heat your water.

steelman99 wrote:Has anyone here added battery storage to their solar panels ?

With the recent increase in electric prices Im considering it , been quoted around £3.5k for a battery storage system but as usual theres a few types to consider.

Some people have suggested one that charges the batterys from solar in daytime and from a cheap eco 7 tarriff overnight , some a system that charges batterys straight off the panels , others that allow my inverter to convert the power to AC , then use another inverter to convert it back to DC for storage

other thing is Im not sure how much spare electric we actualy send back to the grid . Parents have got a smart meter that shows when power is going back to the grid , but not how much is actualy been exported - had considered seeing if i could get an export meter fitted for my own info if it was a cheap option to see how much I actualy send back

The more I read , the more I become confused

On the other side as far as the solar is concerned I see Decembers RPI was 7.5% so thats the increase we get on the FIT from April , so now over 60p per unit that I generate

The reason you're confused is that there are lots of well intentioned people giving advice who haven't actually run the numbers or fully understand how battery storage for a home user works. I've spent loads of time looking at it and I get the payback to over 40 years on electricity prices from 6 months ago when I last ran the numbers. I guess maybe now that is down to 25 years if prices stay as high as they are going to be.

If was financially worthwhile there would be companies popping up everywhere and frantic TV and radio advertising. The lack of this tells us it's not economically worthwhile.

The question I always ask is, if its economic for me to do at home, why isn't it being done commercially? After all they have economies of scale and better bargaining power. A home user has their roof/garage as an asset, small local demand, perhaps government subsidy, and available capital, but still the numbers don't add up until you include the extra term, accepting a poor return on capital, "because its the right thing to do", something companies won't do to any great level.

And of course if the payback time is decreasing by more than a year a year, you'd be wise to wait until the technology matures before buying, unless you have annual green budget to spend.

scrumpyjack wrote:The other option is that AFAIAA you can get a device that turns on your hot water tank immersion heater when you have surplus solar energy so that it gets used to heat your water.

We have this installed, it works very well and I would recommend it.

Gan020 wrote:

steelman99 wrote:Has anyone here added battery storage to their solar panels ?

With the recent increase in electric prices Im considering it , been quoted around £3.5k for a battery storage system but as usual theres a few types to consider.

Some people have suggested one that charges the batterys from solar in daytime and from a cheap eco 7 tarriff overnight , some a system that charges batterys straight off the panels , others that allow my inverter to convert the power to AC , then use another inverter to convert it back to DC for storage

other thing is Im not sure how much spare electric we actualy send back to the grid . Parents have got a smart meter that shows when power is going back to the grid , but not how much is actualy been exported - had considered seeing if i could get an export meter fitted for my own info if it was a cheap option to see how much I actualy send back

The more I read , the more I become confused

On the other side as far as the solar is concerned I see Decembers RPI was 7.5% so thats the increase we get on the FIT from April , so now over 60p per unit that I generate

The reason you're confused is that there are lots of well intentioned people giving advice who haven't actually run the numbers or fully understand how battery storage for a home user works. I've spent loads of time looking at it and I get the payback to over 40 years on electricity prices from 6 months ago when I last ran the numbers. I guess maybe now that is down to 25 years if prices stay as high as they are going to be.

If was financially worthwhile there would be companies popping up everywhere and frantic TV and radio advertising. The lack of this tells us it's not economically worthwhile.

My solar installation cost just over £5000 in 2018. Based on my numbers I expect to break even by the end of 2023.

When I considered solar installation my priority was return on investment not the break even point. I could have left the £5000 invested somewhere giving me 2 or 3% return or I could use it to install solar panels that gave me 20% return pa.

Battery storage is a different ball game.......

richlist wrote:
My solar installation cost just over £5000 in 2018. Based on my numbers I expect to break even by the end of 2023.

When I considered solar installation my priority was return on investment not the break even point. I could have left the £5000 invested somewhere giving me 2 or 3% return or I could use it to install solar panels that gave me 20% return pa.

Battery storage is a different ball game.......

My solar installation (4.225KWP) cost £4000 in December 2020.

Last year (2021) I saved £274, which is a return of 6.8%, and my breakeven year is 2028.

The options I was given including a battery, were much worse. I have an electric car anyway so I wouldn't consider a domestic battery.

FD

In my case the return is made up of ......the reduced use of grid electricity & the FIT payments, which are in two parts (UK Gov' & energy supplier).

We also use the solar panels to heat the domestic hot water via an immersion heater so there is a saving on gas which was previously used to heat the water.

I wish I could find somewhere to put £4000 that would give me a 6.8% inflation beating return.

richlist wrote:In my case the return is made up of ......the reduced use of grid electricity & the FIT payments, which are in two parts (UK Gov' & energy supplier).

But unless you have a time machine those arrangements are not available now, so any consideration for an installation now should be based on what they are now.