Economy 7 - Electric vehicle BUT working from home.

baverchr

Hi all, first post so forgive me if this has been discussed before. 
We're about to move into our first home and will be purchasing an electric car. For this purpose I have researched that an Economy 7 tariif is the way to go.

However, due to the whole COVID situation, I will now be working from home permanently and my wife 3 days a week (50 mile round trip in said EV the other two days). 
Does it still make sense for us to go E7? I am worried with the increased day rates and us both consuming two PCs worth for the entire day that over time we may end up paying more. I guess this is down to individual tariffs and research, but also how much energy the PCs, Monitors etc use on the average day. 

Does anyone have experience of such things? Do EVs use enough kWs over the year to average out cheaper regardless in this instance?

Very niche question I know, but wondered if anyone had any experience.

Many thanks!

Talldave

There are dedicated EV tariffs but which one will suit you will depend on the balance between EV charging and everything else. Laptops etc don't use vast amounts so daytime use might be low, in which case paying a high peak rate to get a really low EV charge rate might be worthwhile. On the other hand, a cheap single rate for everything might average out ok if the car only needs an occasional charge.

I'd suggest going on a cheap variable rate on moving in (eg Symbio or Neon Reef), buying a decent energy monitor (eg Geo Minim+) and carefully measuring use during the day/night/car charge times. Fire your results into a spreadsheet and work out if there's an EV tariff that will be cheaper than the single rate approach (eg Octopus).

My "vision" for smart metering is that we should have a dynamic market where you can switch energy supplier on the fly overnight when say Tesco do a buy one kWh get another one free offer, and be back with your default daytime supplier in the morning. But that's just a dream for now.  Octopus is about as innovative as it gets, with products like Go and Tracker.

The other approach is to buy a Powerwall battery system, top it up on E7 off peak (in parallel with EV charging) and then all your daytime electricity is at time-shifted off peak rate! Throw in solar panels as well for additional self-sufficiency. Of course your EV itself is a Powerwall on wheels but I don't know if the technology exists yet to use it as such?

MWT

baverchr said:

However, due to the whole COVID situation, I will now be working from home permanently and my wife 3 days a week (50 mile round trip in said EV the other two days). 
Does it still make sense for us to go E7?

We are in much the same position, no need to recharge the car every day and working from home with a couple of PC's on at all times.

The typical EV tariffs like 'Go' from Octopus or the original Bulb Smart tariff didn't really work for us as we weren't making full use of the overnight cheap rate (we have gas for heating so no benefit there).

We've ended up on Octopus Agile which has daily variable pricing for each half-hour of the day, and we are currently averaging under 7p/kWh with a daily standing charge of 21p.

But... with Agile it is important to minimise your use of electricity during the 4-7pm period when the demand and hence prices are much higher.

We cook with electric but we don't typically start cooking until after 6pm so at most the last hour of that period catches us a bit. That is included in the 7p figure above though so it clearly isn't hurting us all that much.

The only thing we don't do in the 4-7pm period is use high consumption devices like a drier or lawnmower and minimise cooking.

Worth a thought for you at least...

Gerry1

Can you have two MPANs, probably with different companies, one for the house itself and one just for the EV?  You could have say Neon Reef on a 12p-ish single rate for the house and Octopus or someone supplying five hours overnight at 5p or whatever.  If the EV tariff charged 50p/kWh in the day it wouldn't matter !

matelodave

Two MPAN's would cost you two lots of standing charges. TBH without getting too clever the OP would probably be just as well starting off with a cheapish single rate tariff and do as suggested above and monitor the consumption to see when it's all getting used - I've got an Efergy Engage, which just clips onto the main incomer and then sends data back to a server every six seconds - I can either view in directly on my computer, tablet or mobile phone or download it it to a spreadsheet (by the minute, hour or day). You can just get the transmitter/receiver - you don't need an actual display if you don't want one - just view it when you want where ever you are., there's no ongoing cost.
https://engage.efergy.com/

In fact I've got two Efergy's  (Maplins were flogging them off at £25 before they went bust - one monitors my household consumption and the other is monitoring the heating.

 there's also Loop, which looks a bit similar but I have no knowledge about it - https://loop.homes/what-is-loop/)

Gerry1

matelodave said:

Two MPAN's would cost you two lots of standing charges.

True, but it could be cost effective.  If you drive 10,000 miles per year at 3 miles/kWh that's 3333kWh.  If you're paying 5p/kWh on your second MPAN instead of 12p/kWh, the saving of 7p/kWh amounts to £233.33 which will happily pay the extra £91.25 standing charge and still leave you £142.08 better off.  Of course, you'll need a beefy charger, but you'd probably want that anyway.

MWT

Gerry1 said:

matelodave said:

Two MPAN's would cost you two lots of standing charges.

True, but it could be cost effective.  If you drive 10,000 miles per year at 3 miles/kWh that's 3333kWh.  If you're paying 5p/kWh on your second MPAN instead of 12p/kWh, the saving of 7p/kWh amounts to £233.33 which will happily pay the extra £91.25 standing charge and still leave you £142.08 better off.  Of course, you'll need a beefy charger, but you'd probably want that anyway.

It is easier to just go with Agile, I have the EV.Energy app set to charge my car whenever the price drops below 5p/kWh, doesn't matter what time of day that happens to be.

Having two MPAN's would require paying for a second meter install as well wouldn't it?

As for the 'beefy charger' that is pretty much always built into the car, the wall box is really just a power supply, so for most people that means 32A/235V available so about 7.5kW unless you go 3 phase. How much of that you can use is down to the car.

It is just the 4-7pm period to consider, no need for anything exotic if you don't have very high use in that time slot.

Gerry1

MWT said:

Gerry1 said:

matelodave said:

Two MPAN's would cost you two lots of standing charges.

True, but it could be cost effective.  If you drive 10,000 miles per year at 3 miles/kWh that's 3333kWh.  If you're paying 5p/kWh on your second MPAN instead of 12p/kWh, the saving of 7p/kWh amounts to £233.33 which will happily pay the extra £91.25 standing charge and still leave you £142.08 better off.  Of course, you'll need a beefy charger, but you'd probably want that anyway.

It is easier to just go with Agile, I have the EV.Energy app set to charge my car whenever the price drops below 5p/kWh, doesn't matter what time of day that happens to be.

Presumably the Agile tariff requires a smart meter?    I'd be happy with a second MPAN and E7 meter if it were cost effective, but a smart meter would be a red line for me.

matelodave

So the OP could do some simple sums - if he gets around 3miles/kwh then a 50 mile round trip will use approx 16.6kwh at 12p/kwh = approx £2.00. Based on an e7 tariff at say 8p/kwh (off-peak) and 16p/kwh(peak), he'd spend £1.34 to charge the car, saving about 60p a trip. (put in your own figures to do your sums)

Based on the three journey's a week he could save £2 with a bit of shopping thrown in. BUT everything else is costing him 4p/kwh more (than a flat rate 12p/kwh) so the peak consumption would have to be less than 50kwh/week to off-set it - that's n o more than 7kwh a day.

Just playing with the numbers and doing a lot of what-ifs can give all sorts or results. If she started working five days a week then the off-peak consumption would increase and the peak would go down a bit but conversely if she stopped working they'd end up out of pocket

Perhaps setting up a spreadsheet and juggling a few numbers about could give him the optimum tariff - then he's got to find it and ensure that he sticks with the monitoring to ensure that he's still maintaining the optimum split (doing the washing, cleaning and ironing overnight during off-peak hours would help skew it the right way  )

MWT

Gerry1 said:

Presumably the Agile tariff requires a smart meter?    I'd be happy with a second MPAN and E7 meter if it were cost effective, but a smart meter would be a red line for me.

Yes, Agile requires a smart meter (Tracker doesn't, but that isn't as cheap for me as Agile).

I know that is a line you will not cross, but I'm saving so much more money by having the smart meter and access to Agile that I'll never willingly move away from this sort of tariff.

baverchr

Wow, thankyou all so much for this, plenty to get thinking about and its seemingly not as stupid a question as I first thought.
I will most likely find the cheapest rate electricity tariff I can to begin with and use the smart meter/energy monitor to work out exactly how much we use on an average day. Once we add the EV in I can then add to the maths over a month or so and try and work out whether changing to Agile or E7 would make a marked difference. It will likely take some time, but I'll be sure to post here with the results.

I have seen a few posts now around batteries which is veeeeeryy interesting. I hadnt thought of charging it on the low tariff times I thought you could only use them with Solar. If thats the case, I'm sure we could run all the laptops/screens off of one during the day to save even more.