Changing The Way I Calculate Solar Value

Over the last few years, I've put quite a bit of work into our solar generation stats, tracking generated electricity value and calculating when the install will break even. The calculations marry each kWh generated with the Octopus Agile import cost at the time, using an additional calculation to account for the lost export value of anything charged into the battery. The logic used is quite complex but, in theory, generates an accurate representation of generated value. However, it is also fundamentally flawed: if we didn't have solar (and, in particular, the battery) we wouldn't be using Octopus Agile. Prices change every 30 minutes and can be unbelievably cheap (negative even) or preposterously expensive - the whole point in it is load shifting, without a battery peak times would be ruinous. This means that the numbers don't tell us very much about what we're saving compared to not having the system at all. So, I decided to build a simple report which calculates the value of solar…