The Fourth Step in Creating a Net Zero Building: Evaluating Energy Measures

At Page, we pride ourselves on being at the forefront of green architectural design, the implementation of sustainable practices, and we strive for environmental friendliness and cost effectiveness in every building we design. In a series of posts, Page Associate Principal and Senior Design Architect Peter Hoffmann details the methodical approach that Page used for a net zero-targeted multifamily project for the benefit of other designers also seeking to create an energy- and cost-efficient building.

The Fourth Step in Creating a Net Zero Building: Evaluating Energy Measures and Creating the Optimal Strategy

The first step in managing the list of Energy Efficiency Measures (EEMs) is twofold: First, eliminate any strategies clearly unsuited for the project. Various reasons may include regional factors such as climate, the availability of technology and costs incompatible with the budget. Second, identify any subsidies including those at federal, state and local levels that will generate return through tax incentives, rebates and other forms of compensation.

Then, determine which of the EEMs under consideration are eligible for the various programs.  Finally, confirm whether any strategies are required by local code issues or pre-selected rating systems prerequisites such as LEED. This will help the energy team organize their list of possible EEMs into three categories: definite strategies to include, strategies to be evaluated and strategies that can be discarded.

The energy team on a project we'll call the Riverside Apartments project identified several incentive programs.  Most were run by the local power utility and the largest potential rebates were for photovoltaic systems. Given the net zero goal and the need to generate power on-site, this moved a minimum 260 MW solar array strategy into the Definite category for this project.

When the team evaluated green roofs, that strategy was immediately eliminated due to climate, incompatibility with the wood frame structural system and extremely low projected return on investment.  They also eliminated several cutting-edge technologies that were still experimental or not readily available, and thus unsuitable for a commercial project without subject matter experts on the owner’s staff to provide continuous support.

Once definite strategies are identified and others discarded, it is time to evaluate the remaining list of EEMs. There are several ways to do so: 

• Energy reduction/generation potential
• Initial cost
• Operational costs (fuel, maintenance other life cycle costs)
• Local climate considerations
• Local availability of technology
• Seasonal load variations and rebate structures
• Constructability and integration with other building parameters

This is the fourth in a series of posts on designing NetZero, or low energy consumption, projects based on a white paper by Page Associate Principal Peter Hoffmann. To see previous posts, click the links on the right hand side of the page.