Zero Net Energy + Historic Preservation: Turning a Building From the Past Into a Model for the Future
Our community has long been a progressive one, with leaders and local activists often pushing for change and setting new standards for the rest of the state (and at times the nation) to consider. In July 2019, with unanimous support from councilmembers and community members, the City of Berkeley City Council passed a law banning natural gas from new development. Councilwoman Kate Harrison, who sponsored the legislation, cited that “natural gas is a leading source of greenhouse gas emissions (GHGs) in Berkeley, responsible for 27% of the GHGs released in the city,” and 73% of its building sector emissions.
Berkeley’s shift toward electrification will result in buildings operated on cleaner, safer, and renewable energy (electricity in Berkeley is 78% carbon-free) and paves the way for energy conservation. Throughout California, a similar statewide mandate is promoting all newly constructed and renovated commercial buildings to consume zero net energy by 2030. ELS believes in this effort and is working with our clients to help meet this goal. In fact, in 2013, we joined the AIA 2030 Commitment to achieve carbon-neutral construction by 2030.
Our team at ELS fully supports and promotes efforts to go carbon-neutral. Coincidentally, when the new law passed, we were about three-quarters of the way through construction documents for the renovation of the Live Oak Community Center, a City-owned building, built in 1956, that currently uses natural gas. When ELS was awarded the Live Oak project in early 2018, the primary focus was on seismic, life safety, and accessibility upgrades that would support the building’s transition to a “first use facility,” meaning it would become a safe shelter for emergency evacuations. Converting the building from gas to electric energy was not part of the original scope or budget.
Our initial schematic designs proposed the reuse of existing equipment, including gas furnaces, appliances, and other equipment. But in early 2019 (even before the ban became law), the Berkeley City Council asked all City departments to prioritize the elimination of natural gas service in all City projects.
On the surface, it may seem counterintuitive, but older buildings can offer many opportunities for energy reduction and conservation. At the Live Oak Community Center, the existing building shell consisted primarily of concrete masonry unit (CMU) walls, single-pane glass windows, uninsulated wood-framed walls and roofs (which is fairly common in California’s moderate climate), and natural daylighting. The CMU walls act as thermal mass which collects heat from the sun and then slowly and naturally releases that heat into the building. In simple terms the building has thick exterior walls, so heat doesn’t get in quickly, and thus doesn’t require extensive cooling systems. And while the historic aspect and budget of this project did not include full window replacement of the existing steel sash windows, these windows were already operable and provided natural daylight and ventilation for occupant comfort. With all these factors in play, we had a reasonable baseline for energy efficiency. The renovation plans included all LED lighting, the addition of rigid insulation in the roof, as well as solar-reflective cool roof shingles that reduce heat gain, all of which improved the building’s energy performance even further.
Converting the building from gas to electric would pose additional challenges and opportunities. The building’s overall energy efficiency, operational costs, and GHG emissions would all immediately improve with electrification. Typically, this kind of conversion would include the addition of photovoltaic (PV) solar panels to generate enough electricity on-site to offset the building’s electric usage. However, the renovation budget for the Live Oak Community Center had been established long before the mandate for electric conversion was issued, so ELS and several consultants working with the City collaborated to determine the best path forward based on costs, effectiveness, and ease of installation.
These changes allowed the facility to slightly increase its building area and comfort while still lowering its Energy Use Intensity (EUI). The original program included additional administrative areas for staff serving the community. However, the administrative area was west-facing, and the staff had been concerned with overheating. The new HVAC system was reworked to serve the additional area and provide cooling which was not previously part of the original building systems. We were pleased to find that our conceptual model’s performance was lower than both the existing EUI average, and similar facilities’ average.
The revised mechanical design incorporated electric heat pumps for the community center’s social hall (the building’s largest interior space), and “variable refrigerant volume,” or VRV systems in the renovated classrooms and new administrative offices. HVAC ductwork, conduit, and pipes are designed to minimize the impact on the historic building character. The existing gas water heaters, gas furnaces and gas cooking range in the kitchen for the community center will also be removed and replaced. And finally, the upgraded roof and new electric system are designed to be “solar ready,” so that PVs can easily be added later when more funds are available.
With Berkeley’s progressive stance on many environmental policies and practices, it is likely that Live Oak will not have to wait for long. Clients like the City understand that investing in such upgrades as PVs now will cut their operating costs in the long run – and for the long term – by reducing, or even eliminating, their electric bills as the sun becomes their primary energy source. And with the 2019 Public Safety Power Shutdowns of electrical grids, PV would allow the facility to continue to operate as a ‘first use facility’ in future emergencies.
By leading the way with its new electrification law, Berkeley offers other cities around the country valuable lessons-learned that can be applied to similar fuel-switching programs. Additional California jurisdictions including San Jose, San Luis Obispo, Santa Monica, and Windsor have adopted similar electrification requirements. Nationally, states like New York, Virginia, Pennsylvania, and Massachusetts have adopted or are considering moratoriums on the use of natural gas. Based on my own experience with this Live Oak Community Center project, and others, there are six things to consider when converting a building to all-electric: