E7/10 or standard tariff?

[Nick1c]

We have had our overhead supply dropped to a cabinet at the base of the pole and an isolator switch fitted. I was planning to have a standard meter fitted, but after reading about  @JSHarris use have started to rethink things. 

Our plans are to build a reverse level house using 300mm I-beams for the walls with a passive slab and 400mm I-beams for the roof with warmcell blown in. There will be 17 Pv panels on the roof facing due south at 22 deg, heating (& possibly cooling) via UFH & an ASHP (with a couple of heated towel rails in the bathrooms), DHW via sunamp(s). A woodburner will be fitted in the living area. If the majority of the use of electricity is on space heating is it sensible to "charge" the slab overnight using the cheaper rate, in spite of the fact that this is when the house would ideally be at its coolest? The estimated energy use is around 19kwh/m2 per year. According to EDF (our current supplier) if over 35% of power is consumed at off peak rates E7 becomes worthwhile, I do however feel a bit twitchy about the limited choice on E7/10 tariffs. 

What would those better informed than me suggest?

[Jeremy Harris]

With a wood burner and your predicted energy usage I doubt you will need much heat from electricity, will you?  The smallest wood burner is going to chuck out at least 2 or 3 kW into the room, for maybe 5 or 6 hours on a burn, which gives you around 10 to 15 kWh of heat into the house.

 

That leaves DHW, which for us is pretty much our greatest consumer of electricity, albeit from the excess PV generation for a lot of the year (even now excess PV seems to be delivering around 1/3rd of our DHW requirement).  If you believe that your DHW energy requirement will be high enough to make E7 worthwhile then go for it.  For us, it's really my car that swings the balance, being able to charge it at E7 rates during the winter makes a significant difference.

 

SSE changed our meter in about 30 minutes, and didn't charge for the change, so it's not a major issue if you decide you can make good use of E7 once you have a better idea as to your pattern of electricity use.  Originally I worked out that E7 wasn't worthwhile for us, and it's only really getting an electric car that made me reconsider.  Once the balance had swung over to the point where E7 looked a better option, then I tried switching the heating over to run at the cheap rate, and found that it works OK for us.  However, we are all-electric, with no other energy sources, plus our annual energy use is lower than yours, around 12 kWh/m².

 

If I were in your position I'd just leave room for an E7 meter (they are a fair bit taller than a standard meter) and have a standard meter fitted for now, then keep an eye on your consumption when you've been in for a while and work out whether it makes sense to switch.

[Nick1c]

Thank you @JSHarris. That sounds like a plan. 

[ProDave]

Our electricty usage is interesting. We don't use much for space heating (ASHP) and even less for DHW (also ASHP)

 

What is more annoying is we are racking up on average 90-100KWh of electricity each week on "stuff" which basically means everything except hot water and heating,  The "stuff" using more than heating and HW combined.

 

So don't get hung up on your expected heating load.  If you end up like us you will be chasing other things to find out what is using so much.  PV will reduce the daytime consumption of the "stuff" no doubt.

 

Like @JSHarris I have thought about E7 but it does not make sense for us at the moment.  My preference is to use as much in the daytime to self use as much PV as possible with nothing on at night (I like a silent house at night)

[Roz]

Through octopus energy you can sign up to their Agile rate, which is a little like E7 and E10 but varies more. If you don't like it you can just switch to a regular rate. It doesn't require a different meter apparently so you're not stuck with either one. We're going to do this and just see how it goes. 

[ProDave]

10 minutes ago, Roz said:

Through octopus energy you can sign up to their Agile rate, which is a little like E7 and E10 but varies more. If you don't like it you can just switch to a regular rate. It doesn't require a different meter apparently so you're not stuck with either one. We're going to do this and just see how it goes. 

How does that work?  How with a single rate meter does it know what to charge when? or does it require a smart meter?

 

More importantly how do you as the consumer know when it is cheap so you can turn on the big appliances?

[Jeremy Harris]

Agile requires a Smart meter, and as long as you can deal with the high peak time tariff by load shifting then it can work OK.  Octopus Go is similar, but offers a really low off-peak rate of around 5p/ kWh, but only for four hours in the middle of the night.  Go also needs a Smart meter.

 

We were with Octopus at the last house for a time, as they took over from Iresa.  TBH, their hippy style of communication got up my nose, as I didn't appreciated being addressed by only my first name or having every communication from them signed off "Love and Peace".

[Roz]

Yes it does need a smart meter, which seems to be a good idea anyway (?) 

 

I've heard that about their comms before. I haven't received any 'love and peace' that I've noticed though. However, I do think they're quite open about their tariffs. I asked for evidence of the agile rate from the last 12 months in my part of the country and they send me a huge spreadsheet really quickly with all the information I needed to figure out what my local averages would have been. So I was quite pleased with that. Plus I like how flexible it is so you can switch back to regular tariff if you want to. I'm not sure how many other energy providers offer this. 

[Jeremy Harris]

If it works for you then that's OK, but it's worth bearing in mind why smart meters are being rolled out and why the energy companies are spending millions on promoting them. 

 

Smart meters won't save consumers money in the long term, that's not why they are being rolled out at all.  The problem that smaller energy companies, in particular, and the government regulator, who wishes to promote a more level playing field for energy supply, has is that energy is sold wholesale on a 30 minute spot market, with the price varying widely from hour to hour.  It can even go negative at off peak times, so generators have to pay suppliers in order to take their energy, as well as rising to close to, or above, the retail price, so suppliers lose money selling it to customers. 

 

At the moment, suppliers take that market risk.  They try to guess what the wholesale spot market will do over the next 12 months or so and then set their tariffs so that they can make a profit.  Unfortunately, with such a volatile market, and one that's been made more volatile with the increase in variable generation capacity (wind and PV) and the decrease in steady generation capacity (mainly nuclear), small suppliers often aren't able to stay in the market (plenty of evidence for small suppliers going bust, seven collapsed in the UK last year alone).  The big suppliers may well have enough reserves to weather a bad spell in the market, hence the concern over unfairness.

 

So, all the suppliers have been lobbying hard for years to try and get rid of the risk they carry in this volatile market and place that risk on consumers.  Nothing particularly wrong with that, except the best way to do it is to introduce a means of being able to adjust tariffs every 30 minutes, so they track the wholesale price and then persuade consumers that this is being done for their benefit.  The suppliers then carry no risk, and can just charge the wholesale price, plus their operating cost, plus their profit.  It's a guaranteed profit scheme for suppliers.

 

The problem comes when consumers want to try and compare prices.  The only way to do that is to compare the average price, however, that's not very representative.  For example, those who have electric storage heating and live in a cold part of the UK are pretty much fixed as to when they need energy, they can't just turn off their heating if the price rises for an hour to around 30p/ kWh (which it is predicted to peak at when the fully agile market is established).  Most consumers won't have any way of being able to accurately predict their energy bill from one month to the next, as they will only know the price for any 30 minute slot after the event, or very shortly before.

 

Tariffs like Agile and Go are really aimed to get users to fit smart meters, with the incentive of a tariff that, right now, may look attractive.  However, once everyone is locked in to smart metering, then it will be near-impossible to make a judgement as to which provider gives best value, as that is bound to depend on trying to compare 30 minute prices against an exact pattern of energy use over a year.  The suppliers know this; the pricing model will be more complex that that used by mobile phone providers, and that complexity isn't likely to result in best value for the customer.

 

The other problem with smart meters is related to data security.  The data standards used are far from robust, and there are clearly some privacy concerns over that.  For example, think how useful it could be if a household's energy consumption pattern changes, such that someone with ill intent could be fairly confident that the house was empty.  That's a pretty trivial example, but it illustrates just one potential vulnerability in the data handling system for smart metering.