The End Of The Solar Dance

Apologies for the lack of updates on the projects for managing solar, but something happened in January that changed everything.

My original solar installer wrote to us suggesting a battery upgrade for the house. They provided a lot of data on what we had used and when since the installation. They had a payback that was at around three years. Since I’d done a lot of the maths the previous year, I pushed all the data into a spreadsheet and it became obvious that this was the way forward for us.

The battery costs had plummeted post the scarcity around the pandemic. My calculations showed a slightly quicker payback so we pushed the button.

So why do I say this is the end of the solar dance? Our energy supplier Octopus has a fantastic tariff for EV owners (Intelligent Octopus Go). At the time of writing all electricity consumed in the house between 23:00 and 5:00 is charged at 7.5p kWh. The new capacity of the household battery exceeds our normal daily usage (bar car charging). In addition, our solar export rate is currently 15p/kWh so from a purely economical point of view its better to charge the battery overnight rather than during the day.

So now we charge the house battery up to 100% every night alongside any car charging. During the day the battery is kept topped up to 100% when solar is available and any spare is passed out to the grid.

I initially had some ECO concerns over keeping the battery topped up and taking advantage of the arbitrage opportunity during the day. However, after a few conversations with folks, shifting all our load to off-peak and providing additional energy during peak hours is probably the right thing to do.