Solar PV installations like mine that are a few years old generally qualify for the UK’s Feed-in Tariff (FiT) which pays both for generation and notionally for export, while newer installations are covered by the Smart Export Guarantee (SEG). The older FiT scheme was universal in the sense that all larger electricity companies had to participate and they all paid the same rates, while with the newer scheme there’s still an obligation for larger companies to participate but the rates are all different. Older installations like mine can optionally swap the export component of the FiT for the SEG, but is that an attractive option?
SEG payments differ widely between providers so it’s worth shopping around.
My FiT export payment is currently 5.38 p/kWh on a deemed export basis, which means that, rather than measure actual export, it is assumed that half of my generation is exported. My electricity supplier Octopus offerers one of the best SEG rates at 5.5 p/kWh but that’s on the actual export, not the deemed export.
|Alternative||Description||Energy exported||Rate paid||Total||Comment|
|Baseline FiT||2,098 kWh (50% of 4,196.1 kWh)||5.38 p/kWh||£112.87|
|Scenario #1||Switch to SEG without other changes||647.1 kWh||5.50 p/kWh||£35.59||68% reduction|
|Scenario #2||Add disable water heating from solar to above.||1,722.4 kWh (1,075.3 + 647.1 kWh)||5.50 p/kWh||£94.75|
|Provide equivalent water heating from gas||1,075.3 kWh||3.2 p/kWh / 90%||(£38.23)|
Octopus Energy does also offer the alternative of a variable export rate based on wholesale prices, akin to their Octopus Agile import tariff, but for export. However it’s my belief that I would need a much larger battery than I have now (4 kWh) in order to benefit from this as it will always be generally better value to use that stored energy to avoid the early evening peak price period (up to 35 p/kWh) than to sell it back to the grid at a lower price and then need to buy more energy myself. If I had a bigger battery (both in terms of energy and power) then I could both meet my own needs and sell back to the grid.
Overall however I think that it’s clear that, with my current relatively small battery and deemed export tariff, I’m better off on the older FiT scheme than the newer SEG scheme even with one of the better-paying SEG providers.