> What makes the policy debate so difficult to resolve is that tariff design is a very indirect way to support residential PV. In Germany, they’ve gone with feed-in tariffs for solar PV instead – a direct subsidy for every kWh of energy coming from your PV system. Much simpler, and allows a reasoned debate on tariff design apart from solar PV policy.

I'm fairly confident this section about Germany is wrong - Germany has feed in tariffs which operate in addition to net metering, not as an alternative. That is certainly the case in the UK, whose system was modelled on Germany's.

Still, the basic point of this post is correct, net metering is an indirect subsidy, but there is an obvious technical solution: using the article's metaphor, to encourage people to eat their own zucchinis, or to use the solar energy on-site rather than automatically exporting it to the grid.

At present, PV systems export generated electricity directly to the grid, separately from the grid-connection used to bring in electricity which is consumed on-site, all of which is imported. Solar could fulfil normal electricity demand, and also be used to charge up storage heaters, or storage a.c. To the utilities, the house would look like any other, except with lower electricity demand.