Octopus Flux rates change - penalises export again

I am so peed off at Octopus. They drop the amount they pay for export way more than the amount they charge for import. It's almost a 24% drop since April in what they pay us for exported power at peak time, but the import cost has only dropped 18%. I'm even more annoyed because the three hours cheap rate 2am-5am only gives me time to half-charge my batteries, but I don't have an EV so can't go on a tariff that has a longer cheap rate time. During winter, there is no way I'll be able to get through peak rate 4pm-7pm without pulling from the grid.

During winter, we use 25-30kWh a day. We have a Gen 2 5.0kWh hybrid with 2x 9.5kWh batteries (19kWh total). What tariff would you think be best? I don't want to use Home Assistant to schedule charging because it's too darn complicated. I have tried to set it up, but it's too hard, and ended up with me getting somewhat sweary and shouty!!

On the other hand, it looks like they're maintaining the difference of 11p between import and export prices at all times. So the drop in numerical terms, rather than percentages, is exactly the same.

If you can't store enough for the whole day, and there's not enough sun, perhaps it's better to pause the battery during the daytime rate, so that you can preserve the battery for use during the peak rate. If you have to import, better to do so at the day rate, rather than the peak rate. Might be simpler to just charge for a bit longer overnight, even if that does use some day-rate power, though that won't be quite as efficient due to round-trip losses.

If you're not going to be exporting much during the winter, would Flexible Eco 7 work better for you ? In my region, July price is 15.92p overnight (so cheaper than flux), but 38.27p during the day (more than Flux day rate, less than peak rate). Just depends on whether you can get enough in the battery to get you through the daylight hours. And shift enough additional load overnight, such as washing machine and dishwasher.

I came to same conclusion for myself as well

Basically we are in the same place we are now but end result will be lower on both counts.

If anything im miffed that OP was getting his cheaper than me ><

Not going to complain about cheaper leccie throughout winter though since ill be relying on an unreliable battery that never fully charges and less sun.

miffy Some have had success with switching to Go online but some have had to change to the SEG tariff first for export.

I too saw the new prices email tonight. Hadn’t appreciated that there is an 11p difference between import and export, but had concluded that this makes it even less worthwhile to unnecessarily charge the batteries overnight if the next day is going to be sunny and the batteries would fill anyway with solar generation - starting excess solar export earlier in the day and earning about the same as having charged for import overnight in the flux period.

Of course as the solar days get shorter there will be less export anyway so what the export rate is becomes less of an issue.

miffy I too expect to use about 20-30kW a day in winter, but I only have 14.4kW of battery storage.
I aim to avoid the peak rates by overnight charging (depending on next day’s solar), and then either holding the battery value by changing the reserve%/stopping discharging during the day, or do an extra afternoon charge.
Holding the battery SoC will be more efficient (and less cycles) than an extra charge.

I’m also thinking about going onto Octopus tracker for December-February to free me of worrying about the different time of day rates

geoffreycoan Hard to know when a good day will be when its getting dark quick and sun is lower.

Jellybaby If you haven’t already, do create an account on solcast and add the solcast integration to give you predicted solar figures. You dont need to be running any of the battery management automations; I’ve been using it with a few simple entities on a custom dashboard to track my current & future generation

- type: entities
entities:
- entity: sensor.solcast_pv_forecast_forecast_today
- entity: sensor.sum_ge_pv_energy_today
- entity: sensor.solcast_pv_forecast_forecast_remaining_today
- entity: sensor.solcast_pv_forecast_forecast_tomorrow
- entity: sensor.solcast_pv_forecast_forecast_day_3
- entity: sensor.solcast_pv_forecast_forecast_day_4

The sum sensor is a custom helper that adds my two PV arrays together

geoffreycoan I got a solcast account but last night at like 3am it was saying no higher than 1.5kwh peak for today best case and next few days, just woke up and next two days say around 3kwh

Jellybaby Hmm, that’s strange.

Assume you have an automation in HA to periodically (say 4-6 hours) call the solcast API and get the latest forecast?

I’d say mine is fairly accurate, maybe a touch over-estimating so I may need to check my roof angle entered which I think I took from the survey rather than measuring it. By the end of the day PV generation is usually pretty close to the daily estimate But it doesnt jump significantly

Here’s today’s energy graph and its tracking fairly well.

The Solcast "forecast" changes minute by minute and I'm not sure its much use (in my case) for anything other than a snapshot forecast to decide the overnight SoC level.

Basically if you watch the Solcast forecast graphs hour by hour on the portal you'll notice it changes quite dramatically on some days, strangely always towards becoming more "accurate" 🙂

Its a free service for personal use and as such is fine, so I'm not moaning, merely observing...

Its clearly of much more use to commercial users.

geoffreycoan I don't have a permanent home for HA yet and im a bit hesitant to buy one due to the portal transparency issue I ran into with a full days readings, everything but grid voltage and battery power wasn't a solid color and it was hard to read, it was like transparency was turned to 90%

miffy there's always the Octopus Go Tariff

If you want "dead simple to set up" in the Cloud Portal just set batteries to charge to 100% during the Cheap Rate

4hrs @ 5kw = 20kwh so you will get a full charge during the 4 hour slot.

It's then upto you if you want to try and manually guestimate/adjust the % SOC each day using weather or Solcast (or both).

If you don't then the worst case is you loose 1p/kWh in the difference between cheap rate and export rate.

Cheap Rate 00:30 to 04:30 @ 9p/kWh
Standard Rate 04:30 to 00:30 @ 29.78p/kWh
Outgoing Fixed Lite Export @ 8p/kWh

Yes it's, technically, an EV Tariff but tell them you have an EV on Order - that's if they even ask you

You could also start the application process for Scottish Power Export @ 12p/kWh but that's going to take a few months,