Graphing the percent capacity of accumulators would show when more accumulators are needed, and how close you were to running out on previous nights.

The user could check a box that would add the graph to the power chart, always scaled to 100% (top) and 0% (bottom), overlaid on the production ...

When saving, there should be a warning when overwriting another map that doesn't have the same map exchange string. It is common for users to have more than one version of the same map, but it is usually unintended for a user to overwrite a completely different save.