Mandatory solar panels are not the biggest deal here.
When the California Energy Commission announces its new building energy efficiency standards, the big news everywhere was the requirement for solar photovoltaic systems on every new house. In our coverage I noted:
Almost everybody is so excited about the solar, but I am more excited about the efficiency improvements. A lot of people are still burning gas for heat, and solar panels don't change that. Going net zero electricity is very different than going net zero carbon, which is much easier to do if you make houses radically more efficient.
Architect and Passive House expert Bronwyn Barry goes into much greater detail in Media Misses the Meat of California's Energy Code Announcement where she notes that this is "a remarkable sea-change." She notes the mention of "demand responsive technologies including battery storage and heat pump water heaters” and writes, "This is big. It signals a clear move towards the electrification of buildings – a big step for California where gas has been the fuel of choice for many years."
What I’m reading from this carefully worded document is a clear statement of recognition by the CEC that the real issue we’re facing is not an energy use one, but one of carbon emissions. This requires a more nuanced balancing act between consumption and generation, which includes all the elements they’re now encouraging: efficiency, electrification, storage, grid responsiveness (insert your own interpretation of that phrase here) and just the right amount of generation.
Perhaps most significantly, they are walking back from the previous goals promoting Net Zero Energy. This writer has never been a fan of net zero because generating capacity still had to be there for the times of the day and the year when the sun didn't shine, and because rooftop solar disproportionately favored people who had nice big rooftops. It also ignored the carbon emissions from natural gas used for heating and hot water, which is why I promoted radical building efficiency that reduced demand rather than increasing supply. Bronwyn Barry notes:
Now it must be stated that I am not philosophically against the idea of ‘Net Zero Energy’ buildings, nor do I bear any animus towards its supporters and advocates. I’ve personally designed a number of buildings that readily exceed that target but have come to appreciate the wisdom in the CEC’s new direction: energy efficiency is all about minimizing carbon emissions, not ‘zeroing’ energy use out. With renewable generation, that’s about time of use (combined with an ability to store excess energy.) If we are to achieve deep reductions in building carbon emissions, our goals must be twofold: 1. peak load reduction (winter and summer, but mostly winter. A topic for a longer post…) and 2. electrification. (Assuming utilities will take care of storage.)
Pierre Delforge of the NRDC notes that irrespective of the solar panels on the roof, the changes to the energy code are significant:
Better insulation and windows required by the 2020 code, combined with solar panels, will reduce energy use in single-family homes by a whopping 53% compared to current code. This will prevent 700,000 metric tons of carbon pollution — the equivalent of zeroing out emissions from 115,000 cars.
But he also complains that there has to be more movement away from fossil fuels.
Zero-net electricity falls short of zero-net-energy and more importantly of zero-net-emissions. The new code doesn’t fully address one large remaining source of energy use in homes: the direct, onsite combustion of fossil fuels like natural gas and propane for space and water heating, which represent more than one-third of emissions in the building sector.
Finally, Martin Holladay of Green Building Advisor asks why all states can't be like California and do this, noting that "The answers, of course, are cultural as well as political." But he thinks it will eventually happen:
Let's imagine a family who buys a new home in Georgia, and let's imagine that the new home happens to have monthly utility bills of $150. The family visits cousins in California who happen to live in a new home with monthly utility bills of $50. At that point, the Georgia cousins are going to wonder, “Why can’t builders in Georgia make houses like they do in California?”