Not sure I really agree with all these design choices. The color scale on the hour/day grid initially seemed backwards to me. The daily total takes up so much space that it would be better as a normal line or point graph with scaled axes, instead of trying to guess the correspondence with the color.

Aside from that I am curious about the discontinuity at 22h. How many and what kinds of loads automatically respond to these price signals? Just heaters and water heaters?