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Comment by rcxdude | Hacker News Reader

Rooftop power (or other local generation) has a big economic incentive behind it, which is that the energy it generated essentially goes for residential rates as opposed to wholesale rates (which is at least in part actually born out by a reduction in the utilization of the grid). So I expect it to continue to happen, despite it being less efficient in theory than grid-scale. Local battery storage has a similar incentive, but even more accessible (at this point, a home battery system is likely a better house upgrade investment than solar).

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Selling rooftop energy for residential rates isn't economically sustainable, and has already been eliminated in California unless you are grandfathered in.

This is because only a small fraction of the residential rates goes to production costs, and the rest go to distribution infrastructure and operations. Distributions and infrastructure costs/ kWh go with more residential production, not down.

Think of it this way. With commercial power you might pay 0.10/kWh production and and 0.30wh distribution. You can make your own rooftop for 0.35/kw, but the grid still costs the same or more, so that gets added to your bill.

Residential rates for rooftop solar only ever made sense as a huge subsidy for early adopters.

I don't mean net metering, I mean if you use 1kWh from your solar panels that's 1kWh you aren't buying from the grid. That's the big advantage which doesn't depend on subsidies.

The key point is that the difference between "wholesale electricity" and "retail electricity" is based on total costs which don't change if you buy 1kWh less from the grid - while it's currently priced "per kWh", it's not really a marginal cost but a fixed one, so people in aggregated would have to pay the same total amount to the grid no matter how much home solar panels are built.

There is a cost advantage currently, but that is a side-effect of how we currently do accounting of grid costs, not reflecting any actual advantage in reducing total costs across the country.

Exactly. Lets say you and your neighbors each pay $100. You put in solar for $90, and save $10. Because most of the power grid costs are fixed, your neighbor is now has to pay $200 to pick up the slack.

This is why California is now considering grid connection taxes, which would charge homeowners for electricity they generate at home.

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