where next for me with energy storage and extra generation

[Countrypaul]

Have you checked whether you are actually better off on the day/night rates rather than fixed single rate? Using figures for my area and supplier you are, but only by £3 over the 5 months so yours might be worth checking (lower standing charge for single rate also).


Getting a battery and moving more to night rate would obviously make the day/night rate more beneficial.

[SafetyThird]

I wouldn't even bother with givenergy, it feels like a product you never truly "own" and you are one firmware update away from it not working.

Pylontech is kind of the oppersite, which is attractive to some people. We should probably organise a group buys especially the new 5000s.

If you can find an installer the new Huawei battery modules are interesting purely because each is independent so you can quite quickly build up a very large discharge rate if your DNO (and budget) has allowed it.

For inverter, I am a big fan of the cheap as possible strategy. Just replace it if it goes pop. Any monitoring can be done with superior standalone systems like emon, although I have grown to like lux powers hybrid, it's very simple and works well

Yes, I know how you feel about Givenergy but they seem to be building and expanding and apparently are evening looking at a UK base to build their batteries. However, I'm looking at a 20 year lifespan here in the current house and I'm geeky enough to be happy poking it around and tinkering that the Pylontech is attractive and modular and could be changed out without needing to change everything else as well.

[SafetyThird]

Have you checked whether you are actually better off on the day/night rates rather than fixed single rate? Using figures for my area and supplier you are, but only by £3 over the 5 months so yours might be worth checking (lower standing charge for single rate also).


Getting a battery and moving more to night rate would obviously make the day/night rate more beneficial.

I did look into it but until recently so much of our usage was night rate that E7 made sense. Since having the GSHP installed, that's changed a lot so I'm looking at other tariffs along with things like a battery and more PV. I think having off peak will work well with the battery but there's different off peak tariff's too so plenty to get thinking about.

[nowty]

Nowty Towers runs 99.6% Off Peak, you just need a big enough battery.

And a big enough battery inverter.

And a big enough battery charging capacity.

And a 100A DNO fuse.

[Andy]

You can have a smaller fuse into the house with an E10 tariff. The longest period you need to bridge on the batteries is 6 hours

[Joeboy]

Nowty Towers runs 99.6% Off Peak, you just need a big enough battery.

And a big enough battery inverter.

And a big enough battery charging capacity.

And a 100A DNO fuse.

Same here, only by fluke or SWMBO starting ironing when I'm up near the 4kW discharge limit will we touch the grid and that's rare as we both know to cascade events. 100A fuse is handy especially in deep Winter when you are compressing everything into the window. I am a 5 hour window and it does the lot. Peaked at just under 90A.

[Moxi]

I'm going to drop a bit of an idea just before i turn in for the night: happy to be shot down by the morning.

The main issue seems to be needing heat from the heat pump in the winter months, now in order to get that from the heat pump you need expensive batteries which you can charge up with some solar (any wind I don't recall?) or from the nasty expensive grid. you then exchange the stored electricity with a COP of more than 1 to get heat.

Question : is there advantage in a large (very large?) thermal store and a ground mount solar array to store some heat to assist the heat pump to get the required therms you need in winter, but also got the option to harvest some DC if you need electric and not heat.

Now i know direct heating some water or other media is a COP of 1 but the question i am grappling with is how much thermal store and solar panels can you buy for lets say the price of two pylontech batteries and does combining that set up with the HP result in a better COP for the heat pump and a better longer heat delivery period than "burning" the equivalent 4kWh from the two batteries? Also with an integrated thermal store you could use the WBS (assuming its got a boiler) as another heat input source ?

Moxi

[nowty]

No amount of Solar PV in winter will cut it, it just wont.

Wind power will most of the time, but most of us need a share of a big one like the ripple wind turbines as one in our back gardens either wont get past planning permission or simply wont work because we live in an unsuitable place.

If you can get a cheap rate tariff which aligns with gas price (like Go, Go Faster, Intelligent), then a thermal store (heated with heatpump or immersions) or storage heaters is as good as gas for cost and usually (and increasingly as grid becomes less carbon intensive) less carbon than burning gas directly in a condensing boiler.

I know where your coming from because my heat pump wont cut it in the really cold times without extra heat from my storage heaters. Today quite a bit of excess heat from Solar went into my storage heaters but its end of March, not end of December.

I don't have a WBS but Joeboy now seems to almost get away without gas by using his and he's in a colder place than either of us.

[rogeriko]

Lakeside Towers does the same. Only im not as rich as Nowty...

8x 170ah Powersafe batteries @ £100 each 2 years old from BT.
4x 180ah AGM batteries I found somewhere years ago.
1x 5kw 48v inverter from ebay £450.

Total cost £1250. Octopus go 7p at night 32p during the day. Success 45kwh per day usage.

Batteries charging and heating 250L tank with immersion. I have 2500w of solar panels to charge batteries directly but havn't installed them in my garden yet.

[Stinsy]

I'm going to drop a bit of an idea just before i turn in for the night: happy to be shot down by the morning.

The main issue seems to be needing heat from the heat pump in the winter months, now in order to get that from the heat pump you need expensive batteries which you can charge up with some solar (any wind I don't recall?) or from the nasty expensive grid. you then exchange the stored electricity with a COP of more than 1 to get heat.

Question : is there advantage in a large (very large?) thermal store and a ground mount solar array to store some heat to assist the heat pump to get the required therms you need in winter, but also got the option to harvest some DC if you need electric and not heat.

Now i know direct heating some water or other media is a COP of 1 but the question i am grappling with is how much thermal store and solar panels can you buy for lets say the price of two pylontech batteries and does combining that set up with the HP result in a better COP for the heat pump and a better longer heat delivery period than "burning" the equivalent 4kWh from the two batteries? Also with an integrated thermal store you could use the WBS (assuming its got a boiler) as another heat input source ?

Moxi

Intra-day storage is "solved". Batteries and thermal stores to a really great job of taking energy and time-shifting it to somewhere else within a 24hr period. But taking power generated one day and using it several days later is an unsolved problem. It just isn't economical to store energy in that way.

The problem with spaceheating and solar in winter is that there simply isn't enough energy from the sun to do anything. My little solar array provides more energy than I can use on the sunniest days. That is a 5-bed house, and includes car charging, running the washer/drier/dishwasher several times, etc.. However in winter there are loads of days when I get little-to-no energy at all from solar. December 2021 I got 5.9kWh for the whole month. Even a solar array 10x the size of mine (big enough to make Nowty blush) wouldn't scratch the surface for spaceheating.