EDF smart tariff

After looking back at some data from glowmarkt and matching up overnight charging I noticed that the first hour past midnight was still being charged at the higher rate until 6am instead of 5am. Seems like EDF have not taken into account daylight saving hours. I've asked EDF but their support is slow and inconclusive. It'd be good to know if this is just a reporting error or if it will affect bills.

If you or your customers are using EDF smart tariffs it may well be with checking their bill/data!

jd In the olden days, pre-Smart meters, our Economy 7 meter used GMT 365 days of the year. It would seem to make sense today, if you have a smart meter, to shift the off-peak time to align with clocks going back and forward. We're in the process of changing to EdF's EV tariff so we can access their dual rate. Our Smart meter knows what time the UK is currently on, but as we only have single rate, I can't tell whether the time for the change of rate would be set to GMT or BST. We could have done with being on the dual rate already as today is very wet with low cloud and we're struggling to meet the background houseload, never mind charge the batteries. I think we'll be back on the grid this evening until the sun next shines :-(

jd I think Glow data is stored in GMT. The Bright app should adjust and display in BST, but if you used their API, check the timezone on the timestamps.

andrew_bond jd I've just added a tariff section to my Node-RED flow and (for my current flatrate deal) it returns the tariff start date, the standing charge and the unit charge. The API document points you to the end point "https://api.glowmarkt.com/api/v0-1/resource/YOUR-RESOURCEID/tariff" to return this information. I'd expect it to return a start date for dual tariff and the start times for each rate, if that's what you are on. The API documentation also suggests that Hildebrand/glowmarkt store your data in UTC and it could be this that is causing confusion. Their document also says:

All the data we store is saved in UTC (Coordinated Universal Time), regardless of the timezone it was collected in. For the API to correctly return the data for the period you request you must supply the offset in minutes between the timezone you require and UTC. As an example if you wish to request data in BST (British Summer Time, UTC+1) you should specify an offset of -60. EST (East Coast N America) would be +300.

This suggests to me that the meter might be charging you the right rate for the right time period, but it's the glowmarkt data that is introducing confusion. I guess if you put the oven on just after the hour and finish your baking just before the half-hour is up, you could probably work out what's happening from the downloaded data. I think this might be a feature of glowmarkt rather than EdF.

I've also noticed that within the payload returned by the tariff call, there is a currentRates.rate object. If this changes at the appropriate time, you could query this value just after the changeover to check that it had happened before setting your EV/House battery to charge and stop when it changes back. This would mean that any issues around synchronising of times/timezones wouldn't be an issue. I can't test this as I'm on a flat rate tariff but it would be interesting to know.

The smart meter supplied by EDF is matching the glow data. I'm waiting for EDF support to confirm what my current bill is for ultimate confirmation. Also I set my car (with the right time on it) to charge at midnight which corresponds to the increase in demand on the meter. So the time is correct. The billing isn't on both glow and EDF smart meter.

Proof here:

https://dean.so/2022/04/12/edf-issue/

jd If the IHD and Bright app have the same data for consumption and cost, then that's a good thing but it sounds like the tariff is set to GMT/UTC rather than BST. You did well to spot that! In fact, I'm really glad you spotted that because I searched for EV tariff and BST and found a thread on a forum which seems to give the answer. It looks like different suppliers have different policies but EdF's tariff sits on GMT all year round.

I wrote to Money Saving Expert, Watch Dog and the Mail to let them know because undoubtedly this will catch a LOT of people out with their EVs especially! I've scoured the EDF website and yet to find reference to the GMT. In fact the thread you posted is the best information yet I've seen on the subject!

Now to work on some scripting to automatically change various appliances around... That said, it'd be good to get glowmarkt to reflect the timing properly so it can be used as a reference point for the costing. I suppose some energy suppliers don't like giving us the extra hour of cheap rate power considering the BST change is usually 2am from memory!

jd 2am from memory

Yes "two become one", at least on the last Sunday in October.
It would be useful, if you use MQTT, to query your tariff and find out whether the msg.payload.data[0].currentRates object changes in real time. If it did, then querying this value when the time should change could be used to trigger your cheap-rate charging and change it all back when the standard rate cuts in.

As regards the tariff times, I think if you look at your last electricity bill you will find this in the notes at the back. in my case it says E7 tariff 00:30 to 07:30 GMT