As the county fine-tunes its sustainability requirements for new buildings, an update to the county's green building ordinance would make it easier for new construction projects to meet Marin’s electrification goals.
The proposed update comes just a year after supervisors adopted the ordinance, which introduced “electric-favored” pathways for new homes and increased electric vehicle readiness standards. Now the county is hoping to offer more middle ground for new construction or projects that trigger the county’s demolition standard, and to relieve small units of burdensome rules.
The county will mostly adopt California’s green building standards, which become more stringent at the start of 2020. (Notably, the state is requiring that all new homes are built with solar panels.) But county planners are using the ordinance to make their own local enhancements.
Last year’s ordinance required buildings to have additional energy efficiency if they are built with natural gas appliances. “We have had a number of applicants say they did not want to build an all-electric home because they would like to keep their gas stove or their gas fireplace,” Alice Zanmiller, the county’s sustainability planner, told supervisors during the first reading of the ordinance last week. “And as a result of this, because our current ordinance only has your house as either all electric or gas, we fear that homes that like to keep their gas stove are also using gas for a number of other appliances.”
The county is now proposing that buildings with natural gas for stovetops and fireplaces only may have fewer energy-efficiency mitigations. The state estimates that about 7 percent of gas used in a home is for cooking, while 86 percent is used for heating.
Size tiers for single-family energy efficiency requirements would also be removed, so efficiency standards are the same no matter how large the building is. Previously, new homes greater than 4,000 square feet faced higher standards.
To reduce barriers to the construction of accessory dwelling units, the size threshold for complying with green building standards would be increased from 750 square feet to 1,200 square feet, which is the maximum limit of second units.
While the ordinance’s ability to reduce greenhouse gases may be small because of the low volume of new construction in Marin, the county hopes it will have the positive effect of helping people understand the implications of using natural gas. “There are ripple effects that we can anticipate from enhancing understanding of electrification benefits across the county,” Ms. Zanmiller said.
California has adopted a goal that renewable energy and zero-carbon sources supply 100 percent of electric retail sales by 2045; Marin Clean Energy, a local nonprofit energy provider, expects to be able to deliver all of its energy without greenhouse gas emissions by 2022.
Supervisors showed interest in eventually banning natural gas altogether. “How do we tee up that broader conversation here going forward?” Supervisor Damon Connolly asked Ms. Zanmiller. She said that electrification is still a new topic for builders and homeowners and that phasing out natural gas completely would warrant a separate public process.
“But if it was of interest to your board, it could be something that we observe in other jurisdictions, study local pathways and legal options,” she said.
“I think it would be very helpful to match this up with a glide path to a natural gas ban,” Supervisor Kate Sears said.
Building energy use accounts for 29 percent of greenhouse gas emissions in Marin, but the largest contributor is transportation, which accounts for 54 percent of emissions. The green building ordinance requires that every new building parking lot space be capable of hosting an EV charger, partly because creating EV-charging readiness upon construction is more cost-effective than retrofitting it. That requirement would be softened under the update.
“Many of our jurisdiction partners questioned if adding the necessary support infrastructure to 100 percent of spaces would actually result in more EV chargers, which is a great question,” Ms. Zanmiller said. “Nonresidential uses vary greatly, and this is still an evolving field, so we wanted to add some more flexibility within the standards.”
So, she proposed a second option: that 5 percent of parking spaces have a usable charger and only 20 percent of spaces be ready for a charger. “This could quickly increase available EV charging now and allow the county to continue to study the outcomes of this policy,” she said.
The ordinance maintains the requirement that single-family homes be EV-ready, but in an attempt to increase equity, multi-family home requirements would be modified so that instead of requiring 15 percent of parking spaces be EV-ready, there must be one EV-ready spot per residence.
“Our goal is to connect people to resources if they’re interested,” Ms. Zanmiller said.
Moving forward, supervisors will conduct a merit hearing of the ordinance on Oct. 8, after which they can adopt the ordinance. At the first reading, Ms. Zanmiller emphasized that the ordinance is an important piece, but not a complete approach to reducing emissions from energy use and transportation in Marin.
In November, supervisors will hear from county staff for the first time about revised standards for concrete use. Research shows that cement, as a component of concrete, is responsible for 5 percent of global greenhouse gas emissions. The county will explore ways to reduce cement use by using supplementary cementitious materials and limiting the amount of cement needed during construction.