Not sure if it answers your question, but we’ve recently got our export tariff up and running with Octopus. We went for the agile Octopus Outgoing rather than the fixed rate; fixed rate gives a guaranteed 5p/kWh whereas the agile version tells you what the coming day’s half-hourly day-ahead prices will be and then reimburses based on that. Currently, our export prices for the sunny part of the day are fluctuating between about 19p and 30p per kWh, so outperforming the fixed rate many times over.

Of course, given we have a battery, there’s nothing stopping us charging up from the grid at night and discharging when the export tariff peaks. However, we’re being less mercenary than that and just exporting at time of solar pv generation when the battery is full. Nonetheless, using 12th March as an example, we consumed in total just under 18kWh and exported about 10.5kWh; a pretty cheap day indeed.

Does that help or have I missed your point?

@majordennisbloodnok, you've answered me exactly with what I wanted to know. A follow up question – do you have to be on Agile for your electricity consumption tariff?

@editor, specifically no. In fact, you don't even need to be on an Octopus consumption tariff. They state quite explicitly that you can be consuming via another energy provider and feeding back into the grid via Outgoing Octopus - whether fixed or agile.

The only prerequisite for either of their export tariffs is that you have a smart meter so they can get half-hourly readings.

@majordennisbloodnok you also can't be on octopus go - they state that specifically

You can't be on Octopus Go and Outgoing Octopus. So if you wanted to use a time of use tariff for charging batteries you would have to use Agile Octopus or a different suppliers time of use tariff. Basically because Octopus Go is already loss making and really a loss leader to assess customer behaviour. 

All large suppliers have to offer a smart export guarantee tariff for excess solar. You don't have to be with the supplier to make use of it. They are all fixed rate though currently, even though the ofgem rules say they don't need to be. 

Outgoing Octopus is a bit different in that it allows export via batteries rather than just excess solar as with the SEG tariffs. 

@Jeff, spot on; I'd forgotten that. Octopus are pretty open with that too, explaining the reasoning behind not mixing Octopus Go and Outgoing Octopus.

Posted by: @majordennisbloodnok

@Jeff, spot on; I'd forgotten that. Octopus are pretty open with that too, explaining the reasoning behind not mixing Octopus Go and Outgoing Octopus.

Yep. It is really important to remember that tariffs like Go bear no resemblance to reality. 

Octopus have warned manufacturers about designing systems that rely on the Octopus Go current pricing. Of course there will be differential pricing but be careful about assumptions when designing a solution and business case over a long period. 

Very, very interesting. Are there any other providers in the UK that provide time of use tariffs other than Octopus? Essentially, from what you guys have said, I could have a smart export tariff with Octopus and a time of use of tariff with someone else, if there is a someone else.

Are there any other providers in the UK that provide time of use tariffs other than Octopus?

If you mean 30min time slots, not as far as I know, not publicly available. Only Octopus has 30min time slot tariffs currently.

Agile Octopus for taking electricity from the grid and Outgoing Octopus for feeding electricity to the grid.

You need a reliable smart meter so the first thing i would do is try and get one fitted. Without it none of this is possible. 

The current issues with the price of electricity has made things difficult for suppliers. 

Plenty of suppliers have tariffs with a fixed number of cheap hours electricity, either economy 7 or an EV tariff for example. 

Essentially, from what you guys have said, I could have a smart export tariff with Octopus and a time of use of tariff with someone else, if there is a someone else.

You can have the Outgoing Octopus tariff for feeding back excess solar and energy stored in batteries. This gives you a variable 30min time slot rate for feeding back electricity. Octopus also have a tariff paying a fixed rate. These aren't typical smart export guarantee (seg) tariffs that you see from many suppliers in that you can sell electricity stored in batteries. 

Then you would have typically an EV tariff from Octopus or another supplier to take energy from the grid and charge a car and some home batteries with off peak electricity. In theory Octopus Go is only available to those with an EV. In practice it is open to those with home batteries even if they don't have an EV. It is not clear how long tariffs like Octopus Go will exist and if they will be replaced by things like Agile Octopus or intelligent systems that choose when to charge individual cars or batteries or even heat pumps. 

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Important to read the small print with all the tariffs and check for limitations, although there is sometimes flexibility.

For example when looking at large suppliers you may see something called a smart export guarantee (seg) tariff. This is only for selling back excess solar directly, not selling anything you might have in a battery.

Some suppliers have tariffs using special EV chargers.

There are specialist tariffs for some home batteries, e.g. Tesla.

It is a bit messy at the moment with a mix of time of use and type of use.

There are lots of trials involving V2G, V2H, electric home batteries, heat batteries, intelligent devices etc so expect a lot of change in the next few years. 

Just to follow up on all this, I thought you might want to see some figures. We managed to get our Outgoing Octopus Agile set up as of 6th March, so we haven't been running a full month. However, the 24 days of data are at least enough to show the general trends.

For top line figures I've been looking at the total energy handled which includes the energy we've imported from the grid combined with what we've generated. Overall, we've generated slightly more than we've imported (50.22% vs 49.78%) and of what we've generated 17.71% of the total handled has been consumed by us and 32.51% exported back to the grid.

Regarding generation, we've 18 x 360W panels - about 6.5kW theoretical maximum - and our best day since 6th March saw us generating 28.3kWh. Interestingly, our largest export was 23.05kWh and that wasn't on the same day, demonstrating that performance over an extended period is more important than the peaks and troughs. On average, though, we've been exporting 12.27kWh and consuming 6.68kWh per day, and seeing an average daily import from the grid of 18.79kWh.

Regarding consumption, it's unsurprising that our ASHP is the biggest draw, and that this month has been both mild enough to see relatively good performance figures but still cold enough for the ASHP to continue being active. Over the time period, we've seen a daily average ASHP consumption of 14.6kWh (max 29.3 and min 6.7) against a daily average of 10.87kWh for everything else.

What the bald figures don't show, however, is the import and export graphs provided by Octopus. Our consumption most days during this time period have shown basically no grid import between about 8:30 and 16:30, and the import from grid is at a pretty constant level outside those times. That means in practice that our two main ASHP hits in morning and evening have been largely fed from the battery, and that the bulk of that imported energy has been during the cheap rate times. The exporting has all been during the same 8:30 to 16:30 (ish) period and therefore at reasonably high prices - between about 15p and 25p per kWh. Fairly obviously, being on the agile version of Outgoing Octopus is dramatically preferable to the fixed rate of 5p/kWh.

As an aside, I am looking at all this in the context of having replaced our oil fired boiler. As I have said elsewhere on the forum, we stopped using oil in mid December last year when oil prices were around 61p per litre, and our yearly consumption was about 2,000 litres. The oil price now is 93.88p per litre, having recently come down from £1.04 per litre. All the tinkering we've been doing with fine tuning the ASHP, with insulating the house and with the solar PV generation, storage and export seems to pale into insignificance with the bald fact most of our savings have come from a world gone mad.