Solar charging my EV - who is good at maths?

QrizB

MWT said:

QrizB said:

MWT said:

QrizB said:

Ohme's "solar boost" as part of a smart charging schedule gets you 7p/kWh for daytime import on IOG. I don't know if you get the same with a Zappi?

No, that wouldn't work with a Zappi, and to be honest I'm not at all sure it should do that on Ohme either, unless it is only happening when a smart schedule is in place, in which case yes, that works with Zappi...

To answer this point, yes. If we plug the car in at say 10am and ask it to be charged by 8am the following day, we might get charging slots for the coming overnight period. Then Solar Boost will kick in at say 12pm and it will start charging with any import at Intelligent rates.

So if you start exporting is that the trigger for the 'Solar Boost' to start? ... or might you be exporting for a while and then the Solar Boost cuts in at a point where, presumably, Octopus have given Ohme an indication that there is capacity to be used...

I'm pretty sure it's the former; if my export reaches the trigger point (about 700 watts) it'll start a solar boost charge even if that particular half hour hadn't been scheduled previously. And it'll carry on into subsequent half hours.

ASA201

QrizB said:

MWT said:

QrizB said:

MWT said:

QrizB said:

Ohme's "solar boost" as part of a smart charging schedule gets you 7p/kWh for daytime import on IOG. I don't know if you get the same with a Zappi?

No, that wouldn't work with a Zappi, and to be honest I'm not at all sure it should do that on Ohme either, unless it is only happening when a smart schedule is in place, in which case yes, that works with Zappi...

To answer this point, yes. If we plug the car in at say 10am and ask it to be charged by 8am the following day, we might get charging slots for the coming overnight period. Then Solar Boost will kick in at say 12pm and it will start charging with any import at Intelligent rates.

So if you start exporting is that the trigger for the 'Solar Boost' to start? ... or might you be exporting for a while and then the Solar Boost cuts in at a point where, presumably, Octopus have given Ohme an indication that there is capacity to be used...

I'm pretty sure it's the former; if my export reaches the trigger point (about 700 watts) it'll start a solar boost charge even if that particular half hour hadn't been scheduled previously. And it'll carry on into subsequent half hours.

When this happens though, which is the scenario I think I’m talking about the amount you draw from the grid should be at day rate, not night rate? 

MWT

QrizB said:

MWT said:

QrizB said:

MWT said:

QrizB said:

Ohme's "solar boost" as part of a smart charging schedule gets you 7p/kWh for daytime import on IOG. I don't know if you get the same with a Zappi?

No, that wouldn't work with a Zappi, and to be honest I'm not at all sure it should do that on Ohme either, unless it is only happening when a smart schedule is in place, in which case yes, that works with Zappi...

To answer this point, yes. If we plug the car in at say 10am and ask it to be charged by 8am the following day, we might get charging slots for the coming overnight period. Then Solar Boost will kick in at say 12pm and it will start charging with any import at Intelligent rates.

So if you start exporting is that the trigger for the 'Solar Boost' to start? ... or might you be exporting for a while and then the Solar Boost cuts in at a point where, presumably, Octopus have given Ohme an indication that there is capacity to be used...

I'm pretty sure it's the former; if my export reaches the trigger point (about 700 watts) it'll start a solar boost charge even if that particular half hour hadn't been scheduled previously. And it'll carry on into subsequent half hours.

Thanks, that does sound wrong then, but I can see why it is useful if you are on FiT.

ASA201

MWT said:

ASA201 said:

MWT said:

... but recently at least, if I connect after 11:00am I'm getting a lot of daytime slots on the Zappi anyway, but I'd usually avoid doing that as it is more profitable to export the solar at 15p rather than 'saving' 7p by putting the solar into the car.

…and hopefully in my case you can see why I would want to put the solar into the car given I’m not on a SEG

How does your deemed export compare to your actual export?

The rate you are getting is low compared to the SEG rate.

Only been in the property 6 months so hard to work out what it would be over the course of the year, particularly as we’re only recently getting into better months.   

I can’t work out how I could possibly be better off on an export tariff when my aggregated rate is 26.43p per kw?   

Am I missing something obvious? 

MWT

ASA201 said:

MWT said:

ASA201 said:

MWT said:

... but recently at least, if I connect after 11:00am I'm getting a lot of daytime slots on the Zappi anyway, but I'd usually avoid doing that as it is more profitable to export the solar at 15p rather than 'saving' 7p by putting the solar into the car.

…and hopefully in my case you can see why I would want to put the solar into the car given I’m not on a SEG

How does your deemed export compare to your actual export?

The rate you are getting is low compared to the SEG rate.

Only been in the property 6 months so hard to work out what it would be over the course of the year, particularly as we’re only recently getting into better months.   

I can’t work out how I could possibly be better off on an export tariff when my aggregated rate is 26.43p per kw?   

Am I missing something obvious? 

You can keep your FiT generation payment, it is only the deemed export that you give up when you move to metered export.

ASA201

This sounds like I need to do a further calculation which will blow my mind 

QrizB

ASA201 said:

QrizB said:

I'm pretty sure it's the former; if my export reaches the trigger point (about 700 watts) it'll start a solar boost charge even if that particular half hour hadn't been scheduled previously. And it'll carry on into subsequent half hours.

When this happens though, which is the scenario I think I’m talking about the amount you draw from the grid should be at day rate, not night rate? 

Here's an extract from a recent bill:

We were solar boost charging in the afternoon. Those 7p slots only "appeared" once the solar boost cut in.

MWT said:

QrizB said:

I'm pretty sure it's the former; if my export reaches the trigger point (about 700 watts) it'll start a solar boost charge even if that particular half hour hadn't been scheduled previously. And it'll carry on into subsequent half hours.

Thanks, that does sound wrong then, but I can see why it is useful if you are on FiT.

I wasn't expecting it to work this way but when the Ohme app said it was all at 7p/kWh, I thought it was worth continuing with! I first mentioned it here.

MWT said:

You can keep your FiT generation payment, it is only the deemed export that you give up when you move to metered export.

I would be better off on metered export, but I can't be bothered with the admin - which I reslise isn't a very MSE attitude

ASA201

QrizB said:
.

I wasn't expecting it to work this way but when the Ohme app said it was all at 7p/kWh, I thought it was worth continuing with! I first mentioned it here

That’s really interesting as is their little 2 and a half minute video which is basically what I’m describing here with my Zappi and what I’m trying to achieve

Interestingly it didn’t say anywhere on that page that it would charge you the lower of the two rates in a solar boost scenario.   

I’ll need to have a wee look at my dashboard when the slots generate in a day or two and see what rate I was charged today during the solar boost.  

QrizB

ASA201 said:

Export prices to Grid (Deemed FiT Tarriff so aggregated amount is my overall ‘sell’ rate per kWh)

• Generation Rate: £0.2286 per kWh
• Deemed Export Rate: £0.0714 per kWh
• ½ of Deemed Export Rate: £0.0357 per kWh
• Aggregated: £0.2643 per kWh

Regarding metered export, it all depends on how much of your generation you're exporting.

If you generate 1000kWh, you're currently paid £35.70 in "export" payments regaerless of whether you export it or not.

Octopus Outgoing Fixed is cutrrently paying 15p/kWh for metered export. For the same 1000kWh of generation:

• If you export all 1000kWh, you'll be paid £150.
• If you export 800kWh, you'll be paid £120.
• If you export 600kWh, you'll be paid £90.
• If you export 400kWh, you'll be paid £60.
• If you export 200kWh, you'll be paid £30.

Typically, a household with solar PV and no domestic storage battery or hot water diverter will export 60-70% of what they generate. You've got a relatively small system and I don't know how much daytime electricity you use, but you might be exporting a bit less than that. Let's say you're as low as 40%. That's still £60 per 1000kWh, rather than the £35.70 you're currently getting. So even at 40% it's a small improvement,

ASA201

Super helpful.    And I guess the challenge is I’ve no way of knowing what I’d be exporting in a year unless I changed our current household behaviour to avoid maximising the use of the solar when we’re home and it’s generating.    

The old chicken and egg