To entend what Michael said, I think that a lot of this complexity will sort itself out naturally as long as we can establish actual cost based pricing. Then consumers will be motivated to seek the lowest total cost solutions and utilities will get compensated at an appropriate level.
I see Demand or Capacity charges being an important rate element. So even in an annualized net-zero scenario, there will be monthly charges for the highest demand required from the utility.
I agree with Al that differential two tier pricing will help to generate utility revenue even on net-zero usage. But it certainly needs to take into account TOU pricing such that solar energy generated in the afternoon is more valuable than off peak energy. And the wholesale rate paid by the utility to buy back afternoon generation might be higher than the retail rate for off peak consumption. In that case the net-zero building owner might still earn a CREDIT for zero net energy consumption. As I say, the rates need to reflect the true costs basis and the rest will sort itself out naturally.