Simple method to enable Charge Anytime with Solar Panels
Charge Anytime sounds like a great innovation for anyone with an EV, but currently does not support Solar Panel owners as it is not possible to distinguish between energy coming from the grid (and liable for credit) and energy coming from Solar (or other home) generation (which would not be liable for credit).
Given that Solar energy is only created during day light hours, the scheme could have a “Charge NightTime” credit scheme, which would probably satisfy most EV and Solar Panel owners. Even during peak summer days, I note that my panels do not generate any electric after 9pm and before 5:30am. I live in Cambridge, so possibly in Scotland there’s a small variance, but I doubt more than 30 minutes. Hence “Charge NightTime” credit scheme could easily operate between 9:30pm and 5am and be satisfactory. (Currently I am on Economy 7 plan and hence only ever charge my EV between midnight and 7am, so this seems very reasonable to me).
Of course, someone may also have a battery associated with their Solar Panel system and could therefore “cheat” the system by charging their home battery from solar and then use the Home Battery to charge their EV at night time and get credit when it is not due. However I would wager that few people have a home battery system that can deliver a sustained 7KW delivery. Most invertors from battery systems are only ~3KW capable. You pay your money and make your choice (if the installer ever enlightened you about such a choice). The biggest I knew of was Tesla’s PowerWall 2 Battery that can deliver 5KW sustained with 10 second short peaks of 7KW. Charging a car is best done as fast as possible, though clearly there are use cases (the final few percent or significantly discharged battery in cold weather) when the charging rate should be lower. Hence to eliminate these possible cheats, a further limitation is placed on when credit is made such that the charging rate is 7KW (probably >6KW is good actual test), which can be validated by both data read from the Smart EV (they always show a charging rate, normally in mph), and even further validated by the Smart Meter in the home. If the charging rate is lower than 6KW, then the credit is not applied, but the car can still be charged at the normal tariff.
IMO, this should be a simple (software) validation test, (ie: after 9:30pm and before 5am, and charge rate >6KW in the car and by the Smart Meter) that would satisfy most EV Users for 95% of their needs. This still provides a 7.5 hour window for Ovo to decide when to charge EVs at low rate, (eg: excess wind power etc) with a potential charge for the User of up to 50KW in one evening.
It’s also fairly simple to explain to customers …..
