I've never seen a tariff incentivising less use (will look into it), but have seen a few timed tariffs. The less use tarriff should be mandated, not a choice though, as a high user is never going to choose it.
I know the timed tariffs are not incentivised enough, as the energy suppliers are split, so trying to get one over on each other. There needs to be some cohesion/ regulation, so that they're working to make things better for their customers, but also for the grid, which ends up better for the customers/ grid/ suppliers also.
Loads of the timed tariffs and overnight EV charging tariffs were pulled when the prices started going up, where as they could have been index lined or whatever. I've been waiting for this tariff for about a year, it was announced and then "not available"
https://www.eonnext.com/tariffs/next-drive
Loads of the tariffs where they give you cheaper energy overnight, they jack up the cost of the rate so much during the day that it's no longer an incentive. Some use you can't move from during the day, especially if you work from home or have kids etc.
It just needs more cohesion, and to be better regulated, with the grid and end users interests at heart. I'm not saying the suppliers are the ones at fault, as they're not the ones making a fortune in the energy mess, that;s the producers. Also a notoriously rough industry for suppliers where loads go bust, and they have to protect themselves. If they were better supported or guaranteed by the government then we would have less of a problem. This is one of the areas where nationalisation could work, albeit whether that's cost-effective compared to the nationalisation of energy production (or any new energy production) is a different matter.