Zero Net Energy Case Study Building

The Zero Net Energy (ZNE) Cookbook project aims to help the residential new construction (RNC) community identify least cost feature packages that could meet a high-performance goal while complying with the California 2019 Residential Building Energy Efficiency Standards. A wide range of building energy features were assembled into a feature pool; features were combined to generate candidate whole building feature packages; and then candidate packages were evaluated via energy modeling and filtered to select the optimal, compliant package. The optimal feature packages are compiled in ninety-six (96) easy-to-adopt Fact Sheet one-pagers, each for a distinct combination of building type, CEC climate zone, and fuel type. The individual Fact Sheets can be used like recipes; hence the name “Cookbook”. In addition to baseline packages for comparison purposes, each Fact Sheet presents two high-performance packages: ZNE high-performance package — a design that meets the ZNE level of performance and out of all candidate packages, provides the lowest annualized life cycle cost to the resident. Zero Net Carbon (ZNC) high-performance package — out of all the candidate packages, the design that achieves the greatest possible carbon savings through energy efficiency features alone, then meets the ZNC level of performance.   The ZNE Cookbook and Fact Sheets are intended to help the RNC market comply with and exceed California’s energy code by outlining example packages that can be used to achieve these high-performance goals. The packages, or recipes, include a vast amount of prototypical design data such as incremental first costs, annual utility bill estimates, and annualized energy related costs. This data can help inform energyrelated decisions very early in the design process. The Fact Sheets can be used by a variety of California stakeholders, including builders, design teams, homebuyers, local jurisdictions, public program administrators, even regulators, and so on. Following the Fact Sheets, this document includes a technical report to detail the datadriven process and methods based on building energy modeling that were followed to develop optimal feature packages and Fact Sheets. The process followed in developing the packages involved creating a pool of various energy efficiency measures commonly installed in the RNC, collecting the initial and replacement costs of these measures over 30 year life the houses by surveying the builder community, modeling the energy savings over minimum code complaint building and corresponding annualized life cycle cost using energy modeling and optimization tool (BEopt), selecting the least first cost, ZNE and ZNC packages, and post processing to increase the minimum solar PV size to achieve ZNE based on TDV factors and ZNC based on carbon emissions factors. The ZNE design approach used a sequential process whereby energy efficiency measures were optimized for cost, followed by adding renewable energy measures. This process is scalable to other building types, construction types such as retrofit of existing building of various vintages and other definitions of ZNE such as based on source energy and ZNC. A few important observations were drawn from the output results for ZNE packages, comparing all-electric and mixed-fuel options. Net utility bills show a clear trend: each all-electric ZNE package has lower utility bills compared to the same package with a mixed-fuel option. In terms of estimated incremental first costs, there is only a small difference between all-electric and mixed-fuel packages. Annualized energy related cost also shows a trend for single-family homes: typically, each all-electric ZNE package comes with a lower cost than the same package with mixed-fuel options. From these three observations, if a ZNE package is desired, it appears that all financial metrics favor the all-electric option over the mixed-fuel option, at least for single-family homes.