The duck curve is a problem for distributed solar because it leads utilities to stopping the flow of energy from solar systems to the grid. As the sun creates "free" energy, this is a waste of resources. Storing the energy for later when demand is higher is the best solution.

When graphed for a typical day, the pattern created by the midday dip in the net load curve, followed by a steep rise in the evenings when solar generation drops off, looks like the outline of a duck, so this pattern is often called a duck curve.

The two big, long-term solutions to duck curvature The more grids can be connected with one another to form larger grids over larger areas, the more spread out the potential for wind and solar will be and the more spread out load will be, both of which will serve to smooth out the peaks and valleys in the curve.

Details: Differences b/w CAISO and CPUC RA CAISO rounds local requirements to the hundredth. CPUC bases compliance off of a North and South Path constraint. CAISO does not look at this system constraint. entire TAC area where the replacement capacity was needed (although this may change with the proposal as well).