The challenging bit is when most of the time of your electricity consumption is very low, or negative if you have solar panels, but you have periods when the consumption is quite high, and you're not always able to control those high loads. For example, we have over 6 kWp of PV panels in the roof, so during the day the house rarely draws any grid power, as the background load is pretty low. At night the load can increase a great deal though, from around the 300 W background level, up to about 3.3 kW whilst the hot water is boosting (if it hasn't heated enough during the day), plus another ~7 kW if the car is charging (could easily be for the full 7 hour off peak period if we've been away the day before), plus another ~ 1.5 to 2 kW for up to 7 hours if the heat pump is on to charge the slab up in cold weather.
These overnight loads dominate our usage, especially in winter, but they vary a lot. The car probably only needs charging a couple of times a week, the heating varies a great deal with the outside temperature and the hot water varies a great deal with how sunny the previous day has been. This means that some nights there will be no additional demand, it will stay at the ~300 W house background load, other nights it could be over 12 kW, perhaps for the full 7 hour E7 period.
This makes comparing tariffs interesting, as I need to compare the hour by hour rate from each supplier against our historic consumption, in order to try and see which comes out on top. Go is a non-starter, because the off-peak period is too short. Agile gets close to E7 at times, but right now seems to be getting more expensive again (although the average has been biased by the recent high price periods).
Trying to decide which supplier to shift to without at least a year's worth of reasonable, hour by hour, usage data, and without access to the hour by hour pricing from suppliers for the same period, would be challenging, although if your usage data was made publicly available then an app should be easily able to make such a comparison (more easily than my five year old Excel spreadsheet!). If we also had home battery storage then the challenge would be trying to work out how much stored energy could be used during Agile peak pricing periods and how much charge could be replenished from primarily solar, with low price periods as a back up.
I have a feeling my brain might start to hurt trying to do this!
The consolation, for us, is that we don't pay anything for electricity, anyway, and don't have gas, or any other fuel, so the whole thing becomes a bit of a pointless exercise. So far this year we've been paid £1,066 for electricity we've generated, plus FiT, and we have paid out a total to date of £536.50 for electricity we've used, including charging the car. The E7 tariff we're on could increase by a heck of a lot before we'd actually start paying anything for energy, so comparing prices is really, for me, just an intellectual exercise . . .
god knows when they'd have let me know if I didn't chase them! Anyway, I'm now torn between Go and Agile, I was set on Agile but now were coming into winter I'm thinking Go may be better. What is the best way to check what the Agile rates are in my area? Also are any of you on Tracker for your gas? If so is it generally better than standard fixed TL rates? Thanks
