This logic would also support getting even a small battery. So if finances don’t allow a big one that you think would take you through your entire night - an ‘averaging’ battery as a solar buffer of even 2.5kwh could be practical to up your self-consumption during the day. Get a modular system and you can then expand later when finances allow
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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
This logic would also support getting even a small battery. So if finances don’t allow a big one that you think would take you through your entire night - an ‘averaging’ battery as a solar buffer of even 2.5kwh could be practical to up your self-consumption during the day. Get a modular system and you can then expand later when finances allow
I've got about 10kWh of useable battery and it's pretty much the sweet spot for me. I use a combination of Home Assistant, Solcast Solar forecast and a Inverter Modbus integration to charge the battery on cheap rate over night to a level that still allows maximum amount of excess solar during the day to go into the battery. This week have had my first two off grid days of the year where my automation decided there was no need to charge the battery overnight on Intelligent Octopus as the next days solar would meet all house load and charge the battery.
WannabeOwner
Well-Known Member
I'm using Solcast - tell it area, orientation, pitch of panel and Lat/Long and it shows prediction of kW (for next 3 days). Its prediction, for following day, at the start of Off Peak is better than anything else I've found ... I then adjust based on how it changes during the morning (e.g. to discharge from Battery after Off Peak but before Sun Up if its prediction of Solar for the day is more than I had expected / allowed for / have battery space for!)
Note that its download data uses a more recent algorithm than the snazzy online graphs that it shows, so probably need to favour the downloadable data
Free for up to 2 configurations (well .. "Per reigistered email address"
)solcast.com.au
I'm using Solcast - tell it area, orientation, pitch of panel and Lat/Long and it shows prediction of kW (for next 3 days). Its prediction, for following day, at the start of Off Peak is better than anything else I've found ... I then adjust based on how it changes during the morning (e.g. to discharge from Battery after Off Peak but before Sun Up if its prediction of Solar for the day is more than I had expected / allowed for / have battery space for!)
Note that its download data uses a more recent algorithm than the snazzy online graphs that it shows, so probably need to favour the downloadable data
Free for up to 2 configurations (well .. "Per reigistered email address"
solcast.com.au
I think I have solcast but it only shows me tomorrows data on the energy graph. I‘ll have a look as I pull the next day figure for my own energy home page to help with a figure (rather than the graph) and if it gave me a couple extra days it’d be handy.
edit just checked and I’ve even set up my north array even though it doesn’t exist yet. I guess I was doing that to help evaluate viability
WannabeOwner
Well-Known Member
This is what I see on their online graphs
This is what today looked like as-of 9PM yesterday:
Didn't turn out quite like that! But the PV I have had has meant battery has only lost 4% from 08:45 - 12:30, my normal daytime battery consumption is 9% per hour
The Actuals may adjust over the coming days (presumably as any of their, delayed, data sources arrive). Each download includes a rolling last-72-hours (i.e. including late-adjustments, if any) and 72-hours forward
WannabeOwner
Well-Known Member
Still got a screen open from 7AM Yesterday, in case anyone is interested. Shows yesterday prediction as of 7AM against actual in the images above
Zilla91
Active Member
What's the shaded bits all about? Struggle to understand the graph, the way the Givenergy dashboard presents the data is much more user friendly
WannabeOwner
Well-Known Member
Shaded is the range of doubt about predictions - so the white bit should be certain, the shaded bit is the possible range, and the line is "current prediction of most likely". I would imagine it is Standard Deviation 95% degree of confidence jobbie
I'd be interested to see an example of their prediction for "tomorrow" please
I'd be interested to see an example of their prediction for "tomorrow" please
Zilla91
Active Member
WannabeOwner
Well-Known Member
Thanks, interesting that Givenergy are using Solcast ... and I like their -3, -2, ... today ... +2, +3 button presentation
Presumable for "Yesterday", or earlier, you get a blue line for the Solcast "Pseudo Actual", and a yellow line for your real actual PV - the extent to which they agree ... or not! ... over time would be interesting
I need the Solcast degree-of-confidence too because that influences what my system will attempt to do "tomorrow".
... and I like their -3, -2, ... today ... +2, +3 button presentationPresumable for "Yesterday", or earlier, you get a blue line for the Solcast "Pseudo Actual", and a yellow line for your real actual PV - the extent to which they agree ... or not! ... over time would be interesting
I need the Solcast degree-of-confidence too because that influences what my system will attempt to do "tomorrow".
Zilla91
Active Member
I think this is what he's talking about, but I think you have to be on full agile, which is quite brave?
Octopus Outgoing East Midlands | Energy Stats UK
View Smart Meter tariff data and graphs that easily show how you could save money using Time of Use tariffs. Get £50 of free Octopus Energy credit.www.energy-stats.uk
Does not need full agile but can't be combined with "GO" or "IO" but you can swap what you are on between summer and winter.
Do you have a heatpump?
What your electricity usage per day excluding EV charging?
I think I could get 8kWh of useable battery working well but having 15kWh would make the software easier as advoids to need of having it empty at the start of a reasonable PV day.
scdoubleu
Member
I also use Solcast, saving their forecast hourly into InfluxDB. They were a little optimistic early on for today, but did correct as the day progressed. This is today's data (visualised in Grafana):
phil4
Member
I'm not sure it really appealed to too many people. I've not yet got a PW, they're on order... but it really didn't appeal to me. Indeed, as someone once said on youtube... and I think they were right... when you have the same import and export rate, the grid is your battery. At which point, what was the point having one?
You might have noticed the new Octopus Flux tariff designed for PV/Battery peeps, for example:
Octopus Flux
The UK's most awarded energy supplier. We're doing energy better - for you and the environment.
octopus.energy
Day Rate - 34p import, 22p export
Flux 2am-5am - 20.4p import, 9.4p export
Peak 16:00-19:00 - 47.5p import, 36.5p export
45p standing charge.
Expect if you've big batteries and solar there's a fair bit to be made there. My quandry is I'm pretty sure my DNO prohibits me exporting battery power (and so not sure how TEP would have worked anyway).
Yes I saw the new flux rate, need to look at the numbers compared to Go ( currently on until July) - I have 19kWh batteries but generally empty them in the day.I'm not sure it really appealed to too many people. I've not yet got a PW, they're on order... but it really didn't appeal to me. Indeed, as someone once said on youtube... and I think they were right... when you have the same import and export rate, the grid is your battery. At which point, what was the point having one?
You might have noticed the new Octopus Flux tariff designed for PV/Battery peeps, for example:
Octopus Flux
The UK's most awarded energy supplier. We're doing energy better - for you and the environment.
Day Rate - 34p import, 22p export
Flux 2am-5am - 20.4p import, 9.4p export
Peak 16:00-19:00 - 47.5p import, 36.5p export
45p standing charge.
Expect if you've big batteries and solar there's a fair bit to be made there. My quandry is I'm pretty sure my DNO prohibits me exporting battery power (and so not sure how TEP would have worked anyway).
WannabeOwner
Well-Known Member
My understanding is that Tesla were able to claw back some funds for TEP customers for whom DNO had not allowed Export by saying "These customers will not import anything from grid (during supply constrained times)" - which is better than "contributing to the over-consumption problem" ... so there is that.
If you have a heatpump and hence large winter electricity usage along with more yearly total PV generate then yearly electricity usage I can see it being very nice.
You might have noticed the new Octopus Flux tariff designed for PV/Battery peeps, for example:
Octopus Flux
The UK's most awarded energy supplier. We're doing energy better - for you and the environment.
Day Rate - 34p import, 22p export
Flux 2am-5am - 20.4p import, 9.4p export
Peak 16:00-19:00 - 47.5p import, 36.5p export
45p standing charge.
Seems too costly compared to Octopus IO for battery charging if running a heatpump over winter, for the peak heating season PV production will be minimal. Flux time is also too short to charge most battery systems in winter.
