How!? The best I've managed is about £1 of savings and that was by sitting with just one lamp on for the hour and no appliances running.
I was I bit surprised too, previous sessions have been around £3, one in the morning between 9am and 10am was only £0.36p.
They calculate the savings by comparing usage for that hour against previous usage for the same hour on previous days. I don't know if it's an average of previous days, a specific day, the same day of the week last week, the same day the previous year etc.
It was a 5pm-6pm that delivered £7, this was the invitation;
Which was more per unit than this previous one in December;
We have an all electric kitchen and it's likely we have the oven, hob, microwave, coffee maker on normally during this hour (as well as those lights), so not having any of that on this time and cooking ealrier/later could have saved a couple of kWh quite easily.
The low 36p payout in the morning however will be due to nothing normally being on then, so no capacity to do any better.
The scheme is not a great incentive for anyone who is already as frugal as Albert Steptoe, they are seeing little or no reward for their already hard efforts. Perhaps a better way would be a measure against overall population average use? Although those using the most (who are the target after all) may see any benefit as too hard to achieve and not bother, defeating the purpose.
Only saved money from reduced supply overheads can be paid back to customers.
I seem to remember some utility or other, can't remember what it was or if its still a thing, charging more for the first few units and then less per unit if you used more. Perhaps the reverse should be the case to reward thrifty consumers, the less you use the less you pay, like the Tax system just a little less broken.