I don't have a lot of hope for people changing their behaviour based on time of day pricing. Sure aluminum smelters etc might have to flag it for a day once every 5 years but they do that currently because there isn't enough power for everyone so please help us out and shutdown for a day instead cause we are going to dump you anyway because we have to decide between giving you power or this other major load such as a big city. Perhaps there is some gradient to this and it is achieved with price signals - but basically the forecast has to be 1000+ $/MWH for a whole day instead of just a couple high prices intervals or hours, and it has to be order of magnitude higher $/MWH not just $200/MWH instead of $80.
If it is a low-wind evening and prices on the grid are higher than normal what fraction of people are going leave their electric cars with depleted batteries instead of charging them? Say a charge takes say 8 hours, there isn't a lot of room overnight to shift the load around. How many people will refrain from charging because it is going to cost you $50 instead of $10? I think the answer to that can be seen from how much people refrain from driving when fuel costs go up. Given that traffic never gets better I would say none!
1) electricity is cheap. it will have to get a lot more expensive for anyone to care enough to change the way they are using it
2) a lot of the demand is inflexible, regardless of price. lights are going to be on, dinner is going to be made when kids are hungry, car is going to be charged overnight because must go to work tomorrow.
there is going to come a point where all wind and solar must have a certain amount of firm capacity - say it has to be able to deliver 50% of nameplate rating for 5 days straight - and this is going to significantly add to the $/MWH cost of renewables. Then after 5 cloudy days in a row (unthinkable!) the output of the solar farm is 10% of nameplate until it is sunny again.