Feb 26th, 2024

Author: donich_admin

Break even day

This was the first day this year we made more solar electricity than we drew from the grid (i.e. the day Octopus pay us money rather than us paying them).

You can see that we use a lot of electricity – around twice typical consumption for a four bed room house (although we effectively have six bedrooms because of the two offices).

The diagram below shows the generation and consumption for all of Feb.

Note that on a clear day, you can see the difference purely based on length of daylight hours. For example in the diagram, 7th, 13th, 20th and 26th.

I also have over two years solar data and can pretty definitely conclude that as far as Argyll goes – solar performance is as follows.

December and January are write-offs. Best day for us was 5 in Dec and 8 in Jan.
November and February are not great but variable – a sunny day in either can break even. Very sunny weather in either month could be finger looking good, but Scotland’s dreich normal could be arsewiping bad. It would be very unusual to break even over the whole month.
October and March are what R calls the shoulder months. Normally we make about as much as we spend.
The rest of the year we are “makin’ bacon”. Typically we always come out ahead in these months. A sunny day in June makes 100KWH.

Considering the year as a whole, we almost exactly generate enough electricity for our needs. If we had a better storage mechanism (an array of PowerWalls for example) we could actually be self-sufficient.