As I blogged about yesterday, the California Energy Commission unanimously approved a new solar mandate for all new residential construction in the year 2020. I spoke to KPCC radio in Los Angeles and Reuters about the decision.

While I think the mandate is sound economically and environmentally, Severin Borenstein at UC Berkeley takes a contrary view on the economics. Severin doesn’t like rooftop solar in general, as opposed to more cost-efficient utility-scale solar, and he foresees problems with ratepayers subsidizing the installations.

For my part, I think it’s clear the state is heading away from the retail credit model of subsidizing excess solar production, which Severin doesn’t like. Instead, state regulators will likely to move to paying the wholesale rate for surplus solar from rooftops, as Hawaii basically now does. So new batteries will likely accompany these home solar installations, because they will be an economically sound technology to capture surplus solar rather than feed it to the grid for a relatively puny wholesale rate. That’s what we see consumers doing in Hawaii in response to the loss of retail credit.

And in that respect, the new commission rules could help, as they also give batteries “compliance credits” to reduce the size of the needed solar system. They also include incentives to move away from natural gas to new homes, as well as other efficiency measures.

Once again, California is taking a strong leadership position on the environment that will benefit clean tech deployment and save new homebuyers money in the process. The decision should be a major boost for these needed technologies.