-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Best energy tariffs
- Thread starter Smiley
- Start date
I'm not sure how granular their bulk buying is on the wholesale market for domestic use, but the suppliers still have to make an educated guess at their customer usage profiles when setting a tariff.
I only have first hand experience of negotiating large scale commercial energy contracts and those are quoted at bespoke half-hourly rates based on the customer's previous 12 months usage profile. So I guess in this situation the supplier is bulk buying that specific supply tailored to the known usage. They even have clauses in the contract to adjust pricing if the usage profile changes significantly during the contract period.
In the domestic market the suppliers don't have this kind of bespoke customer information, so pricing is set based on the average customer usage profile for that tariff, which they will know pretty accurately. If you don't happen to fit that average, then you stand to lose or gain accordingly relative to their other customers. Also if that average user profile changes over time (for example with more people charging EVs overnight) then future tariffs will adjust accordingly. Maybe we are starting to see this trend already with ultra-cheap night rates disappearing as more people adopt solar, storage and EVs. The Go Tariff mentioned above seems to be an exception and is way cheaper than a typical E7 tariff, although restricted to a 4 hour off-peak period.
mikemillar
Member
That surely can't be right. Isn't that what smart meters and dynamic half hourly pricing is all about? Energy prices are fixed every half hour. At the moment your supplier takes the risk, having to estimate a year ahead for fixed price tariffs. With the ultimate smart setup the supplier changes you the price every half hour based on the changing half hourly price he pays, which can even go negative. It's been happening quite a lot in Germany, which has more of the variable solar/wind input than UK. This tariff is available in UK. I saw a post somewhere showing a picture of the guy's meter reading minus 2.4p - he was over the moon! I think Agile Octopus offers it
Introducing Agile Octopus: The 100% green smart tariff with Plunge Pricing but you need high demand smart appliances, water heating, washing machine, electric car? Powerwall 2? to take real advantage of it. Otherwise you've go to keep watching the meter! I know I'm retired but even I haven't got that much time to spare!
As far as taking the risk on mix of usage, Pete is clearly right, unless the supplier can adjust the half hurly price to suit the customer's profile with a smart meter. Hmmm...food for thought. Could be a legal nightmare.
mikemillar
Member
It may well do but go onto USwitch or GoCompare and get the current prices for your situation. Our house had an E7 meter when we bought it 30 years ago (CH, not storage heaters) and the first thing I did was to fit a time switch to the hot water immersion heater. We have a second tank in the flat. Even 8-10kWh per night has made it well worth it for us. Adding the Tesla, even more so. You will probably have to pay to get an E7 meter fitted, or they may insist on a smart meter, with which I understand you can also use the E7 rates.
... but a heavy night time user could be no less profitable than a heavy day time user as long as they get their sums right.
I would have thought that their bigger risk is the early evening peak segment anyway, not the typical E7 night rate.
That would only be possible if the supplier was able to buy energy wholesale in the precise proportion of night and day quantities relative to its customer usage. On average across a large customer base it might get quite close to that point, but individual customers will gain and lose relative to the average. So if you want to save the most money as a domestic customer, you need to skew your usage as much as possible toward the lower rate. The more people who do that, the more the average usage profile shifts and the less you save relative to the average.
If active smart metering was more widespread, then it would potentially help suppliers to offer bespoke pricing for individual customers as we already see in the commercial half-hourly market. Then there would be no winners or losers, everyone would simply pay the lowest price for their specific half-hourly user profile - which is exactly what happens in the commercial market, where price variation among suppliers is now very limited (at least in the HH market)
mikemillar
Member
If you go to Introducing Agile Octopus: The 100% green smart tariff with Plunge Pricing you can download a massive Excel file with the historic Agile Octopus half hourly rates for each electricity region. Quite illuminating. The lowest rate in my area seems to be about 9-10p/kWh with about 16p/kWh for most of the rest and daily peaks late afternoon up to 30p/kWh. At the moment I think I'm personally best off with my night 5.8p/kWh and day 23p/kWh, even with my current 1/3 high/low split. If I get Powerwall 2's my low rate would probably be even better.
mikemillar
Member
And the price did indeed go negative on 8 Dec 2018 between 3.30-5.00am. Was that the night of high winds - lots of wind energy? I don't think i'd want to rely on that for low prices.
That's pretty cool. I'm looking into the Octopus tariffs now, particularly the Go Tariff and this one could be interesting. I've sent them an email as I want to know what happens if I choose one of their 12 month fixed tariffs (which are expensive) as my interim tariff while they organise an appropriate smart meter. I presume I don't have to stay on the interim tariff for the whole 12 months as that would be a disaster! But I also want the flexibility to change back if for whatever reason their smart meter doesn't work (our mobile signal is very poor, but our current smart meter does work). I worked out my savings would be in the order of £600 per annum on the Go Tariff, which is pretty impressive and well worth a bit of effort switching.
mikemillar
Member
That sounds good for you Pete. From what I've read on the web and what Iona of Octopus said, you sign up for one of their standard tariffs and they switch you to Go as son as they can. The Octopus blog says there's a but of a delay in the SMETS2 meters coming out, March 15th they've been told and that could slip I guess, so I don't think they'll switch you until then, and they've probably got a backlog waiting for the installation of the SMETS2 meters. However, If you've already got a SMETS1 smart meter that may be able to use that, which is what the text from Iona's email that I posted indicated. Good luck with that - £600 is well worth having! much more than my switch.
WannabeOwner
Well-Known Member
I'm surprised you are even spending that much, in total, on Electricity for EV - given the modest mileage you do (I think?). Charging overnight (whether on E7 or not) would help the planet too
and if you get into the habit of using Timer on Washing Machine and Dishwasher, and a timer on Immersion, that should improve your savings further - maybe enough, without EV, to offset the higher Day Rate tariffThen you just need a PowerWall
... you could get a Tesla Roof too I suppose ...I'm surprised you are even spending that much, in total, on Electricity for EV - given the modest mileage you do (I think?). Charging overnight (whether on E7 or not) would help the planet too
Then you just need a PowerWall
I did 17k miles last year and my Tesla has consumed 8650 kWh in that period, virtually all with home charging. I'm not sure what the charging efficiency is, but let's say 90%, so that's around 9500 kWh of charging. On average that's about 3.25 hours charging per night, which seems about right.
That's enough charging to push my night time usage up from 15% pre-Tesla to 36% on the Go Tariff (4 hour off-peak) and that would save me £659 over my current single rate tariff, which is only around 0.5p lower than the Octopus Go peak rate anyway. I was surprised at the potential saving myself. The saving on a more conventional E7 tariff is less, but still considerable.
mikemillar
Member
Having just analysed the excel data using sort, I see that of 17000 lines of data, only 80 lines were below 6p/kWh and over 2000 were above 23p/kWh - my new low and peak rates. 4000 were above 16p/kWh, approx industry average price. Thats 5.5 hours above my assumed industry average peak rate. I'm not sure that bodes too well for cost savings. on adynamic half hourly pricing tariff - not what the Go tariff is at the moment , but I expect it will come. I suppose that with smart appliances or very careful consumption adjustment it might work,. I guess that's the point of dynamic half hourly pricing. They're trying to change our habits. I Pity the poorer less informed. I’m glad I locked in to my deal
Can the Model S do smart charging? Or is there a smart home charging point? One could use a smart 13 amp thingy, which are available, and plug in the 13 amp Tesla charger I suppose. I don't think that would trump 7 kW charging in the lowest rate time, if you could know when that was - without getting up in the small hours!Yes, I actually do have a smart charger at home that was installed FOC as part of a trial (Electric Nation - see link below). It can be programmed to shut down or reduce power at times of peak demand. It can be programmed and over-ridden by a simple App.
Electric Nation | Your electric vehicle - Your smart charge
mikemillar
Member
WannabeOwner
Well-Known Member
.
Well that's the both of us then! Thanks for the numbers, I was surprised I had you down for nearer to 10K miles ... makes more sense at 17K. Interesting how that converts to "average hours per night"
Just as a data point: I'm on around 27K miles p.a. and @ 22 MPH I make that 1,227 hours p.a. and, assuming 5 days a week charging, that's 4.7 hours/night. I am assuming the 10% efficiency loss happens before the 22 MPH ... but I'm not sure on that.
For your 17K miles p..a charging at 22MPH I make that 772 hours p.a. and 5-days-a-week average 2.97 hours/night. Might be that your charger isn't that fast perhaps?
Looking at TeslaFi for the past 33 months ... running 12 month average is 376-392 Wh/Mile, lifetime average is 390 Wh/Mile - obviously a lot less than that on long trips,and a bit more when I press the Knight Rider button. I haven't paid any attention to it before, but TeslaFi Totals are missing 12.7% of overall mileage, so that will be trips made with no WiFi, or where TeslaFi was in Deep Sleep and didn't detect the journey at all
Does that make your 12-month average 504 Wh/Mile? Even comparing MX to MS that seems a little high?
TeslaFi says that my home charger efficiency is around 86%, and work 90%, no idea why that is ... (Work is 3-Phase, but only 1-Phase to the wall-charger - cable duct was too narrow ) (Not even sure how TeslaFi can calculate the efficiency ... it only has the car-end of the story surely?)
On that basis my 27K miles @ 390 Wh/Mile = 10,530 kWH p.a.
TeslaFi says that 10% of my charging at Supercharger ("free" for me), and Home/Work is approx 1/3 & 2/3, so Home=30%, Work=60% (a data point: even though I charge at work Mon-Fri, and we don't do a lot of weekend trips, the "visiting client today, need to charge at home" accounts for a fair bit).
So let's say 10,530 kWH p.a.* 30% = 3,159 kWH p.a. @ 86% efficiency = 3,673 @ £0.08 (E7 rate guess) = £294 for my home-cost I think ... So I will now revised the figure I tell on my gas-guzzling Range Rover chums to 1.09 P/mile Bit of artistic-license in there of course ...
10K Miles p.a. equivalent [at my] 390 Wh/Mile = 3,900 kWH p.a. @ 90% efficiency = 4,333 kWH p.a. and assuming no Supercharger and £0.08 (E7 rate) then 3.5p / mile. Assuming 8kW charger I make that 1h30m - 2h5m Hours per night (7 day & 5 day / week charging) for each 10K miles p.a.
Anyone on 20-something-P / mile Business Use Rate should be able to make the sums work!
Much worse efficiency charging at 13AMP I think?
I think deals where your car charger is remotely controlled by Supplier will become A Thing, and in return you will get best rates ... and hopefully have an EV which is actually charged by the morning
Well that's the both of us then! Thanks for the numbers, I was surprised
I had you down for nearer to 10K miles ... makes more sense at 17K. Interesting how that converts to "average hours per night"Just as a data point: I'm on around 27K miles p.a. and @ 22 MPH I make that 1,227 hours p.a. and, assuming 5 days a week charging, that's 4.7 hours/night. I am assuming the 10% efficiency loss happens before the 22 MPH ... but I'm not sure on that.
For your 17K miles p..a charging at 22MPH I make that 772 hours p.a. and 5-days-a-week average 2.97 hours/night. Might be that your charger isn't that fast perhaps?
Looking at TeslaFi for the past 33 months ... running 12 month average is 376-392 Wh/Mile, lifetime average is 390 Wh/Mile - obviously a lot less than that on long trips,and a bit more when I press the Knight Rider button
. I haven't paid any attention to it before, but TeslaFi Totals are missing 12.7% of overall mileage, so that will be trips made with no WiFi, or where TeslaFi was in Deep Sleep and didn't detect the journey at all Does that make your 12-month average 504 Wh/Mile? Even comparing MX to MS that seems a little high?
TeslaFi says that my home charger efficiency is around 86%, and work 90%, no idea why that is ... (Work is 3-Phase, but only 1-Phase to the wall-charger - cable duct was too narrow
) (Not even sure how TeslaFi can calculate the efficiency ... it only has the car-end of the story surely?)On that basis my 27K miles @ 390 Wh/Mile = 10,530 kWH p.a.
TeslaFi says that 10% of my charging at Supercharger ("free" for me), and Home/Work is approx 1/3 & 2/3, so Home=30%, Work=60% (a data point: even though I charge at work Mon-Fri, and we don't do a lot of weekend trips, the "visiting client today, need to charge at home" accounts for a fair bit).
So let's say 10,530 kWH p.a.* 30% = 3,159 kWH p.a. @ 86% efficiency = 3,673 @ £0.08 (E7 rate guess) = £294 for my home-cost I think ... So I will now revised the figure I tell on my gas-guzzling Range Rover chums to 1.09 P/mile
Bit of artistic-license in there of course ...10K Miles p.a. equivalent [at my] 390 Wh/Mile = 3,900 kWH p.a. @ 90% efficiency = 4,333 kWH p.a. and assuming no Supercharger and £0.08 (E7 rate) then 3.5p / mile. Assuming 8kW charger I make that 1h30m - 2h5m Hours per night (7 day & 5 day / week charging) for each 10K miles p.a.
Anyone on 20-something-P / mile Business Use Rate should be able to make the sums work!
Much worse efficiency charging at 13AMP I think?
I think deals where your car charger is remotely controlled by Supplier will become A Thing, and in return you will get best rates ... and hopefully have an EV which is actually charged by the morning
.
Well that's the both of us then! Thanks for the numbers, I was surprised
Just as a data point: I'm on around 27K miles p.a. and @ 22 MPH I make that 1,227 hours p.a. and, assuming 5 days a week charging, that's 4.7 hours/night. I am assuming the 10% efficiency loss happens before the 22 MPH ... but I'm not sure on that.
For your 17K miles p..a charging at 22MPH I make that 772 hours p.a. and 5-days-a-week average 2.97 hours/night. Might be that your charger isn't that fast perhaps?
Does that make your 12-month average 504 Wh/Mile? Even comparing MX to MS that seems a little high?
I've just double checked my figures and I made a small mistake in post #72 in adding the 10% charging inefficiency twice in my numbers. I'd forgotten that in my spreadsheet I had already factored in a 10% charging efficiency overhead in the *8650 kWh I quoted, so my actual car consumption was 7857 kWh over 17k miles.
* note that I'm simply multiplying 7857 x 1.1 for my charging overhead, whereas I think you are working off dividing by 0.9, which gives a slightly different gross figure. Either way it's just an estimate of the charging efficiency overhead.
So it should have been 2.96 hours/night charging at 8kW and an average 462 Wh/mile.
My saving on the Octopus Go Tariff drops slightly to £624 per annum!
I haven't factored in any supercharging in my calculations, but I use them so little that it would have little effect on my results. Since the car obviously knows how much supercharging it has done, it would be good if that total figure was accessible on the trip page.
Thanks for the reality check there, that was a sharp observation!
Last edited:
.
I think deals where your car charger is remotely controlled by Supplier will become A Thing, and in return you will get best rates ... and hopefully have an EV which is actually charged by the morning
Yes, that's kind of what the "Electric Nation" trial I took part in was all about. The output of the Smart charger I have installed can indeed be controlled remotely by the local electricity distributor to protect the local supply from overload . However, it cannot be controlled by the billing supplier, so at the moment it's really only there for physical protection rather than part of a billing tariff. However there is talk about getting a rebate from the distributor for using less peak rate charging.
This may be slightly off the OP’s topic.... TeslaFi is a great system but it’s calculation of power is necessarily an approximation. While it can get the voltage from the API, it samples the current and interpolates. One thing to do is to check after a journey what it records as the wh/m and compare with the car’s own dashboard record. Depending on your car model, year, software version and a few other factors, the values may differ quite a lot. On the settings page of TeslaFi right down the bottom there’s a fudge factor to adjust its calculation to be nearer the car.
It will still only be about right - it could be 10% different depending on the nature of the journey. Given all the sums many of us do to justify the car (!!) just be aware of the accuracy.
It will still only be about right - it could be 10% different depending on the nature of the journey. Given all the sums many of us do to justify the car (!!) just be aware of the accuracy.
Hi All, I've just got my Tesla last week (thanks to all on here who gave some really useful advice in making the decision!). I use Home Assistant running on a £35 raspberry pi to manage my 'Smart Home' - if you're fairly tech savvy its very easy to setup all kinds of automations. There is already a built in Tesla component you can use to build automations - I've got it set up now so that when the Tesla arrives home it can disable my house alarm, turn on the porch light if after sunset and turn on my hive heating.
After reading this thread I think it could be really useful in conjunction with the Octopus Go tariff. You could quite easily setup an automation to start and stop charging the car in the off-peak hours, and to then continue charging if needed (depending on battery %) from a certain time so it reaches around the desired full charge at the time you leave the house in the morning. I'm still waiting for my home charger to be installed, but going forward I'm thinking to switch to Octopus Go and set something like this up.
After reading this thread I think it could be really useful in conjunction with the Octopus Go tariff. You could quite easily setup an automation to start and stop charging the car in the off-peak hours, and to then continue charging if needed (depending on battery %) from a certain time so it reaches around the desired full charge at the time you leave the house in the morning. I'm still waiting for my home charger to be installed, but going forward I'm thinking to switch to Octopus Go and set something like this up.
Similar threads
