First, we acknowledge the extremely important success of the Decarbonization Coalition (buildingdecarb.org) in their efforts to drive the electrification of the built environment. As a result of their work, over 50 California cities/counties have committed to phase out natural gas in new buildings. The Decarbonization Coalition’s traction with municipalities and other entities is advancing the conversation to include all four of the imperative factors that will enable the decarbonization of the built environment — and the achievement of California’s bold climate and efficiency goals.
The above graphic implies a sequential process beginning with maximizing efficiency by employing Passive House protocols — and the actual construction is a relatively linear progression. However, because the factors work synergistically, it is critical that decisions regarding the integration of all four are made early in the design process.(See The Logic of the MacLeamy Curve from a previous EpiPHany.)
As the owner/developer/design team work to create the Owner’s Project Requirements (OPR) they will make choices regarding the avoidance of natural gas, pursuit of maximum efficiency, minimizing embodied carbon, and employment of clean energy. The early and systematic integration of the four decarbonization factors is critical to achieving the desired performance of the building. Each factor impacts the others.
- It is possible to design and construct an extremely efficient Passive House building that includes natural gas for heating, hot water, and cooking — but if you avoid natural gas, utilize heat pumps for heating, cooling, and hot water, and induction for cooking, the already efficient building will produce dramatically less carbon in operation.
- An electrified building is far more environmentally responsible than one that also employs the combustion of fossil fuel. If that same all-electric building is designed and constructed to be extremely energy efficient, it will require fewer renewables to achieve the goals of zero net energy (ZNE).
- A building’s embodied carbon is the sum of all CO2 emitted from the building products, components, systems (extraction of raw materials, manufacturing, transportation, maintenance, and disposal), plus the C02 emitted during the construction process itself. When you minimize the embodied carbon of the building products and construction process, an all-electric and extremely efficient new building will have a much smaller carbon footprint to overcome, in order to reach zero net carbon (ZNC).
- Whether the “clean energy” is from onsite renewables or the grid, an efficient, low embodied carbon, all-electric building will require considerably less energy for operations. The onsite renewable system required to achieve NZE and/or NZC will be much smaller — and if the building uses energy from the grid, every kWh not required due to the efficiency of onsite operations saves two or three kWh from the grid source that would have been required to offset transmission losses.
The early and systematic integration of the four decarbonization factors is the path to a carbon free and all renewable future for the built environment. Thank you to the Decarbonization Coalition for the momentum they are creating, to Passive House Accelerator for the graphic, and to all of you who receive the newsletter for your support of Passive House California.
Author: Jay Gentry