Anyone who’s seen the California ISO “Duck Curve” knows south-facing roof-top solar is not particularly good for utilities. The problem, which appears so clearly in the eloquent graph below, is that daily peak continues to grow, so utilities still have to build out new generation, transmission and distribution facilities. But, household solar reduces overall energy sales, and this is where most of the money comes from to pay for the new capacity. Some utilities are referring to this as the “death spiral.”