The import/export game

It seems to me, reading the forums, that there are quite a lot of people who are charging their batteries on the cheapest electricity that they can buy and exporting it back to the grid when the export rate is highest.

I can see how, in principle, one might make money doing this. However I do wonder whether people have really considered all of the costs. Using round figures to keep it simple, imagine that you buy a 5kWh battery for £3000. Depending whether you get 3000, 6000, or 9000, or 12000 useful cycles out of it, this battery is costing you between £0.25 and £1.00 per charge-discharge cycle. Each charge-discharge cycle of a 5kW battery will earn me five times the export price per kWh, minus five times the import price per kwh, minus the battery cost per charge-discharge cycle*.

I think that I would want to be very sure which cost-per-cycle figure was real before embarking on this idea. And that is before considering things like the "Time Value of Money", TVM - the idea that money held now is worth more than the same amount in the future. In other words, I could simply invest the cost of that 5kWh battery for the same period.

Things are a bit different when it comes to exporting SOLAR power, but in the case of energy that has passed through the battery, battery costs should still be considered.

* Actually, a lot less. A 5kWh battery stores a lot less than 5kWh when you take into account Depth of Discharge, ageing (average ober the life of the battery), charge-discharge inefficiency, etc.

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