This is absurd and demonstrates the lack of basic Science from the administration of the supermarket. I urge the Brits to boycott this particular supermarket. Here is my reason.
Energy conserves. That's call the law of conservation of energy in secondary school Physics textbooks. The so called "ambient energy technology" is ripping energy from the moving vehicles. If they are really serious about harnessing energy, install solar PV on the roof, install heat pump to move the absorbed heat from the parking lot for some other use.
Simply put, this supermarket is STEALING its customers' energy!