Now had panels for over a year, and still no payment for export, made application to British Gas on their forms, but they say wrong format, it will cost ÂŁ75 to move from British Gas, and we are told Scottish Power is also a problem getting the application accepted.
Octopus seems are better, but then one has to look at the rates, it is not as easy as compare EV tariff with EV tariff as Octopus will not give one an EV tariff without having an EV and EV charging point, but British Gas will.
There is a huge difference between Economy 7 and EV tariff, both have peak and off peak, but times and rates change, it seems EV owners who clearly have money to burn, are offered far better rates to storage radiator users, and my EV off-peek is only for 5 hours, not 7.
Solar we want from the South West, as dusk is around 5 pm so 7 hours until off-peak, and off-peak stops at 5 am and solar will maintain house by 10 am, so only 5 hours, between off-peak ending and solar starting. Also in the evening we tend to use more power.
So we have a time, yesterday 13:47 to 16:01 when the battery was full, so |I was exporting, 4.9 kWh in total, down the drain, as not being paid for it, however at 11:02 my battery was at its lowest point at 61% charged, so had I stopped charging my batteries at 03:00 instead of 05:00 I would have used around 600 watt/hours more (my back ground use is around 300 watt, freezers etc. But then if the sun fails to shine, I loose more paying for peak power, to what I would have saved not using off-peak power.
If I look at export over the 21 days this month, 9 of those days, no export to grid, so battery did not fully recharge, so looking at history, better exporting a bit I am not being paid for, to importing more at peak rate.
The rates are 31.31p per kWh peak, and 8.95p per kWh off-peak, the smart meter app can show ÂŁ25.35 not including standing charge, or 162.09 kWh so simple maths average 15.64p per kWh for October so far.
For the home, solar panels without a battery are a bit useless, you need a battery able to deliver 3 kW so you can turn on a kettle, washing machine, dish washer etc, and if a cloud comes over, the battery will bridge the gap. In general a 3.2 kWh battery will do that. Once you have the battery, may as well charge it up over night and so use off-peak power, then we start to look at what size battery will last for around half the time between dusk and off-peak starting, I found I need around 6.4 kWh to do that, so have fitted a second battery. I say half the time, as if no sun clearly no solar generation, or at least very little, and not aiming to store enough power to last the day when no or little solar.
So look on your smart meter app, and see what you use each day, pick the low days, as you can once solar is fitted, decide if to use washing machine, tumble drier, and dish washer that day, so you want a battery about half the size of your daily low use. Larger and you may not get the return, typical guarantee for battery is 12 years, I have calculated just moving the off-peak so it can be used in the day, it will pay for its self in 3 years.
I have saved more money with the battery to the solar panels, when I went to the EV tariff (I do not have an EV) my bill dropped by ÂŁ20 a month, however it needs the inverter, which I would not have if not for solar. I think my inverter is about 5 kW, which means even if my pair of batteries can give me 6 kW, I still can only get 5 kW, but also I hold back 10% in case of power cuts, so even with a grid failure, my freezers and central heating will still run. How long for, depends on state of charge, and how much sun. It does not supply anything else, although I have one socket I could use.
