I was in Maui last month, and was stunned to see that at least half of the residential rooftops had solar panels. Fossil fuels take an expensive route to Hawaii, so I strongly suspect they are a leading indicator. I flew into Phoenix last fall, and saw that less than 10% of the roofs had panels.The utility death spiral is a great example of system complexity that is simple to understand. Solar energy costs have plummeted – so far that in most places you can get electricity cheaper from your own solar panels than you can from a utility. The impact on the grid of people doing so at scale is to lower the overall cost of electricity generation by reducing both peak demand (and so peak pricing) and lowering volume. Utilities are then stuck with expensive physical assets, less sales and lower margins, so they need to increase either the cost per unit of power or impose grid connection charges to customers. But doing either gives customers more motivation to leave the utility – thus the death spiral.