Whether to spend money on more panels, rather than a battery, is an interesting question. If export rates go up in parallel to grid supply rates, exporting becomes more cost effective. On the other hand, if load-dependent grid charges become more widespread, a battery that you can use to shift off the peak (which is valid even in winter) become more viable.
or hedge your bets and go for a bit of both ?
The real problem for me is in summer, when the battery is going to be full in a few hours and the rest of your output will be exported.
Yes indeed if you have nothing to mop up the excess a lot will be exported so at least make sure your battery is sized to cover your evening and early morning needs, consider a solar diverter for hot water and if you have an EV try to have it plugged in during the day. This June before my Powerwall was installed and due to building work I couldn't have my EV plugged into the charger during the day, I exported 324 kWh, half the power my array generated, and imported probably the same again. If my Powerwall had been installed and the EV had been plugged in I would have exported nothing and would have had between 500-1000 miles of free motoring and wouldn't have spent £97 on that imported power.
Having said that I'm seeing that the battery is having a good effect in the "shoulder" months like now where we're past peak solar. The solar generation is now equal to domestic use and the battery is enabling me to be off grid for the last couple of weeks. I think even a small battery could be worthwhile to make maximum use of solar during the day by acting as a buffer/accumulator. For example if you have the washer and drier on using say 2.5 kW and your array is generating 3kW then without a battery you are essentially losing the excess to the grid. Say a cloud moves across the sun and the array output drops to 1.0 kW then you start drawing 1.5 kW from the grid. Having a small battery would prevent the need for grid power during a sunny period day like that.
how effective is using an induction heater in a hot water tank at burning off excess energy vs using a battery? It seems like its a much cheaper option to start with (if you have a hot water tank)?
Energy required to heat 250 litres of water from 20°C to 60°C is 11.63 kWh so heating water would be a pretty good sink for excess solar. In comparison a Tesla Powerwall holds 12.5kWh.
ta. I presume there's gear so that you can trigger the induction loop only when there's excess electricity being generated (so I'm not burning grid electricity on a cloudy day)? What is that sort of thing called so I can google-fu it
The real problem for me is in summer, when the battery is going to be full in a few hours
..... and households generally need the least amount of power!
how effective is using an induction heater in a hot water tank at burning off excess energy vs using a battery?
You're not 'burning it off' - your're using it productively!
Anyway, pretty damn good - you can think of the water tank as a battery in some respects.
Our holiday place is all electric and our 3kWp array basically will provide all our hot water for 3-4 of us every day from May- Sept (just looked and the 210L tank is currently 59.7c).
If you have a tank then a diverter is the very first thing you should install.
Once the tank is up to max temperature the diverter (Immersun) sends power to a standalone heater that's only connected to the diverter and not to the ring main. This caused an issue during the first lockdown as I couldn't go the the house to switch this heater off and the internal temperature was well over 30c!!
If export rates go up in parallel to grid supply rates, exporting becomes more cost effective.
Ha, some chance! I get 4.5p/kWh deemed as export - that said I'm getting over 60p/kWh I generate regardless of whether it's exported or used internally!
solar immersion diverter
Iboost is a popular one for those that like programable gadgets
Solic is a much cheaper more basic unit .
- i use a solic to feed two Oil filled radiators to use up would be exported energy in winter.
The real problem for me is in summer, when the battery is going to be full in a few hours
….. and households generally need the least amount of power!
When I self build I am going to properly investigate a seasonal thermal store, under or in the house, with solar charging and heat pump extraction.
Such as this (Scottish?) product:
https://sunamp.com/en-gb/products/central-bank-mini/
When I self build I am going to properly investigate a seasonal thermal store, under or in the house, with solar charging and heat pump extraction.
Such as this (Scottish?) product:
isn't that just intended to store energy for a ~24 hours (like a hot water tank), rather than seasonally? I can't see it staying warm for more than a week
isn’t that just intended to store energy for a ~24 hours (like a hot water tank), rather than seasonally? I can’t see it staying warm for more than a week
Scaled up it would be great tech.
On that scale it seems somewhat pointless over having hot water tank. A few folk on a Facebook group I'm in have them and they are pretty slow at releasing heat back to water. - think poor combi style
Someone on here works for Sunamps competitors and was rather scathing 😂
They did come up during my research for my uni project but as you say it's a rather low grade heat that needs proper optimisation, it's definitely not a fit and forget product. There have been some trials, East Lothian housing association and somewhere in Northern England. The latter had terrible results but that seemed unsurprising as they were just flung into ancient housing stock with no other work done and largely reluctant participants. A bit like folk who mean that heat pumps don't work because they won't heat a radiator to scalding point.
They're actually a good idea but as always it's down to the execution.
that said I’m getting over 60p/kWh I generate regardless of whether it’s exported or used internally!
This is one of the reasons the energy market is stuffed. Feed-in tariffs should be scrapped now and the money saved used to fund energy for people who can’t afford it.
Interesting about sunamp.
There's a good few self build versions, using big (3m3) sand or water seasonal storage....hmmm
Feed-in tariffs should be scrapped now and the money saved used to fund energy for people who can’t afford it.
New FITs have been scrapped now, and were scaled back a lot before then. In the grand scheme of things there aren't that many people getting FIT at that level, the systems are small and those systems will either finish their FIT period or become ineligible through upgrades or decommissioning at some point. They probably paid a lot of money as early adopters so the incentive was required.
Export tariffs now are a pittance, if anything they could do to rise to match the increased cost of electricity in general.
Yep, the level of FITS we get didn't last very long at all and were quickly reduced.
Our system was expensive but had probably paid for itself by now.
trail_rat:
while this is true – i suggest that you read the rules around the permitted development.
you will find you require a large plot of land as the bottom of the turbine has to be X from the ground – the center of the turbine has to be X from the ground and the whole thing has to be +5m(iirc) – but its for sure X meters from a from any boundary if it were to fall over.
I was just looking at the figures and potential because of where I live. I looked into the issues and problems. Looks majorly scary in terms of vibration and then energy production doesn't seem that good.
Bearing in mind that I've lost two wind speed anemometers in two years, the height required not keen on.
Maybe one year someone will fix the main issues with them but I guess it's just Solar for me.
Shame really because here potentially they could generate a fair bit of power 😉
JeZ
Maybe one year someone will fix the main issues with them but I guess it’s just Solar for me.
I thought a bout a turbine about 15 years ago as we have an open aspect and plenty of space to put one. But the costs where massive and, of course, there's lots of moving bits to go wrong so I think there'd more room for stuff going wrong whereas PV is effective;y fit and forget.
I can’t see it staying warm for more than a week
Maybe they should substitute water for baked potatoes or McDonalds Hot Apple Pies - both of which seem to stay at nuclear temperatures for days on end!
😉
@mrsparkle I had a quote from a company that uses pylotech batteries however they appear to be housed in a floor mounted cabinet which put me off. They wouldn't fit easily in the space I had earmarked. No concerns about quality as they appear to have a good reputation but this and the fact that the the company could not provide a solar diverter to heat our water is a bit of a non starter for me.
With the energy cap now confirmed, how many people are recalculating their payback period on £10K installations?
This would be a real shame and maybe part of the master plan by big oil to keep us hooked on Hydrocarbons?
They win either way as they would keep the huge profits and people keep drawing from the grid....
No mention of a new Green Deal (Energy Company Obligation ECO scheme) to subsidise renewables. Is the % of the Energy Co. profits monitored to see how much the actually spend on these?
I’m not. Mine was only partially based on the economics, we started our search before Ukraine and the price rises. We knew it would cost us, but that it was the right thing to be doing. If anything, I’d want MORE solar. Next year we’re planning to add another 8 panels which should lift our array to a theoretical 8.5kW, but some will be easy and some west facing. We’ll use the extra for solar water heating.
...maybe part of the master plan by big oil to keep us hooked on Hydrocarbons?
could be. Or maybe it's some sort of political ploy?
We'll continue with our planned PV/battery installation.
Perhaps the cap and so on will reduce demand for PV components and cause prices to stabilise or fall?
With the energy cap now confirmed, how many people are recalculating their payback period on £10K installations?
This would be a real shame and maybe part of the master plan by big oil to keep us hooked on Hydrocarbons?
They win either way as they would keep the huge profits and people keep drawing from the grid….
No mention of a new Green Deal (Energy Company Obligation ECO scheme) to subsidise renewables. Is the % of the Energy Co. profits monitored to see how much the actually spend on these?
Solar makes sense, batteries less so. Even at £0.50ppkWh batteries don't make financial sense for my use.
As a two person household who both work full time, a system without batteries doesn't make sense.
Which is why I said for my use. Mrs flicker is at home all day so we can use a good chunk of our generation (around 35%) Over a ten year period the sums for battery storage don't add up even at 50ppkWh, but that's based purely around our own situation.
around 35%)
That's the part that makes no sense without batteries. Unless you can get an immersun or iboost fitted.
With batteries that rises to 85-90% especially if your wfh all day.
I have solar without batteries. Doesn't really make sense at all. Just the battery tech was NMC at the time and I didn't want NMC in my house largely. ..... Life4po was on the horizon but not there yet
We don't work from home, Mrs f is disabled so doesn't work and I'm out all day. We're also fairly low power users, from March to early October our general energy import per day will be around 3-4kWh the rest is covered by the solar panels.
Based on that requirement I'd be looking at around a 5kWh battery using an 80% DoD. Assuming we can charge the battery fully for 75% of the year that's 274 days, that's 1096kWh at 4kWh a day. At 50ppkWh that's £548 per year, £5480 over ten years.
I'd be happy to self install and then it'd be worth it but I can't because a g99 application is required (probably fast track) and for that you need an mcs certificate which obviously I can't provide so it's have to use a registered installer.
Trying to work out just how much we might be able to generate. We have a South facing roof which is great. Unfortunately, half of that is a cross gable roof over the master bedroom which does nothing, not even extra usable loft space.
Our Solar power system went in today: opted for 10 panels split between south facing (6) and east facing (4) roofs (house is three bed semi-detached) with a system power of about 3.7-ish KwH, Inverter and one storage battery.
System was switched on at lunchtime, I'm not sure about the overall power generation yet (will check tomorrow) but according to the system app the battery was at 100% charge by about 4pm and the house was being powered from the panels alone for most of the afternoon. After sunset we were using about 65% power from the battery/35% from the grid when the electric oven was on this evening. Once the cooker was off the house was running fully on the battery supply so that's the lights, fridges, freezer, TV and our usual plethora of USB chargers/smart speakers etc. We're not running the immersion from the system yet but might get this set up later on although it probably means a new hot water tank too.
Some excess power was getting sent to grid earlier. The SEG isn't set up yet, I feel that the monetary value of this will be minimal (read: pathetic) anyway but its money in the bank so we'll do this as soon as the documents come through to allow this to be set up.
Battery is down to about 75% charge now so I reckon it should easily last to sunrise.
I'm interested to see how this all works as the days get shorter but so far so good.
Mine has been in just over a week, I'm one 5kw battery down it's due to be replace this week hopefully. So far pleased with results. Can't apply for SEG yet as I've no paperwork yet.
I’m interested to see how this all works as the days get shorter but so far so good.
Can you get on a time based tariff like Octopus Go? Depends on the size of your battery but filling the battery up at 7.5p per kWh for 4 hours with a little solar top up might get you most of the way through a winters day. Worth doing the sums.
You can’t move to Octopus at the moment. They’re not accepting new customers.
You can move to Octopus right now. You just need to call them up. The regulations don't allow for suppliers to refuse new customers but they don't have to make it easy for you to join.
according to the system app the battery was at 100% charge by about 4pm
I very much doubt the battery would have been supplied with a low charge.
I called last week and again yesterday. On both occasions, they agreed to call me back. So far they haven't.
I very much doubt the battery would have been supplied with a low charge.
Typically, you are supposed to store Lithium batteries at around 60% charge, so my guess is it was at around that level when installed.
Can you get on a time based tariff like Octopus Go? Depends on the size of your battery but filling the battery up at 7.5p per kWh for 4 hours with a little solar top up might get you most of the way through a winters day. Worth doing the sums.
This is exactly what we're doing and have sized our battery according to around 90% of the usage cycle at 13-16kw. We're at the low end of that due to availability.
Mine has been in just over a week, I’m one 5kw battery down it’s due to be replace this week hopefully. So far pleased with results.
@ Bruneep - what size system have you got and where are you?
Some of those numbers don't make much sense.
You can’t move to Octopus at the moment. They’re not accepting new customers.
I moved to Octopus Go two weeks ago. I was an existing Octopus customer so maybe not a completely new customer. The only thing that held up my Go onboarding was them having to switch me from the Octopus Outgoing export tariff to the standard export guarantee. Once that was done the switch to Go took a couple of days. I suggest talking to them as I've found them very helpful on the phone. Its understandable they are going to be snowed under with people wanting to switch to Go but things may have calmed down a bit after the price cap announcement.
Aberdeen, despite the gloom merchants the sun does shine here on south facing roof 😎
5.3kw array
3.6kw inverter
1 5kw battery had 2 fitted one is faulty awaiting a replacement.
What's not making sense to you?
My bills are making sense just now
Yesterday
because your original image showed ~7400kWh of use...
because your original image showed ~7400kWh of use…
.... and 140kWh generation in what,8 days?
This the the generation from my 3.9kWh system for the last 3 full weeks:
2022-36 67.600kWh 05/09/22 - 11/09/22
2022-35 85.800kWh 29/08/22 - 04/09/22
2022-34 81.600kWh 22/08/22 - 28/08/22
I'm much further south (Chester) and haven't had a weekly generation over 130kWh this year (early August) - so your 140kWh further north in mid September sounds rather "amazing".
Edit: And my system here produced 6.9kWh on the 14th and my 3kWh system in N Wales produced 6.4kWh - yours apparently produced 15!!
There are 14 x 395 JA panels on roof
my daily import from grid is around 2kwh a day now,
so on day of install the inverter consumption was started at 7382.1kWh rather than zero there is the issue of funny numbers
There are 14 x 395 JA panels on roof
.... but it's still a 3.9Kwh inverter - that's the maximum it can ever output.
(All standard PV systems in the UK are limited to >4kW output - anything over that requires permission from the local DNO)
I might be wrong, but the generation just looks huge!
Yup a 3.6 inverter.
we have full sun today, maybe yours is under performing 😉
Many hybrid inverters include power drawn from the battery in their “generation” figures. You need to dig a little deeper into the stats to get the actual solar generation total or use something like Home Assistant.
I have 12 JA 395W panels split east/west in North Yorkshire and over the last week they’ve generated between 5kW (rainy day) and 15kW (mostly sunny).
Having to do everything from the website annoyed me so I’ve built an in-home display similar to that you’d get with a smart meter which shows stuff in real time (3D printed case still printing)
