Another interesting little cost conundrum I'm exploring here is lost public revenues due to reduced electrical consumption. This, of course, ignores the consequences of revenues lost by service providers. Furthermore, it isn't restricted to consumption changes brought about by increased penetration of self-generation, but also arises from energy efficiency initiatives, and simple economic downturns.
As an example, here in Ohio we have 1) a kilowatt hour tax, that goes to the State's general revenue fund; 2) a Universal Service Fee, that is used to fund relief programs for the poor (essentially helps them keep their utilities on when they would otherwise be denied service for non-payment); and an Economic Development Cost Recovery fee that subsidizes electricity rates for certain high-demand industries in the interest of job retention.
The first two were actually in fairly dire straits back in 2008-2009, due to general economic conditions. The Economic Development Cost Recovery fund was not so badly affected, as the recipient industries were operating at much reduced levels anyway.
Nevertheless, as demand is reduced, some alternative means to collect these funds must be found.