This past week, the San Diego Green Building Council hosted a two-day conference at the San Diego Energy Innovation Center on the topic of Net Zero Energy/Water. The opening keynote of the conference was delivered by RNL's director of sustainability, Tom Hootman. Presented here is an outline of his "8 Simple Steps to Net Zero Energy," accompanied by some notes that I took during his talk.
Step 1: Define It.
"Net Zero" can mean a lot of things. It is important to define what you mean by "net zero" or "green" to make sure that the entire team is on the same page from the project's inception.
Step 2: Set a Target.
How will success be measured? For example, are you targeting a specific amount of kBTU's that this project will use? Are you trying to identify a reduction of kBTU's based on a similarly sized/operated project? Or are you focusing on lowering the Energy Use Intensity?
These are important metrics that set the stage for design and construction, as well as operations and maintenance.
Step 3: Aligned Team and Process.
"Good fences make good neighbors," Robert Frost wrote in his poem, Mending Wall. For a successful Net Zero Energy project, binding contracts are a necessity. The "meat" of the contract needs to bind the parties to specific energy goals. Project delivery methods are also important considerations.
In traditional project management theory, we are taught that quality, budget and schedule are in conflict, often resulting in compromise. However, Hootman stated that in order to achieve Net Zero Energy, performance, quality, schedule and budget must be of equal importance.
Step 4: Model Like Hell.
Success in high performance design and construction comes from data-driven design. Unfortunately, our current modeling methodologies are not as effective or accurate as we would like. There is a difference between predictive modeling and compliance modeling.
The main point that Hootman seemed to hammer home is that modeling needs to begin at the earliest stages of the integrative design process in order to achieve the stated goals.
Step 5: Start With Passive.
There are lots of neat wiz-bang tools and technologies that have come out in recent years to improve building performance. But starting out with simple and passive means to reduce resource usage isn't just a good idea - it is the heart of good design.
Step 6: Re-Think Active Systems.
Once you have optimized your use of passive principles for building performance, it is often best to take an open-minded approach to the active systems employed. Remember, every building and every project are different. Hootman described several ways in which active systems were employed in novel ways and combinations to reach Net Zero Energy at the National Renewable Energy Laboratory (NREL), incluing de-coupled ventilation, heat recovery from the data center, a layered lighting strategy, etc.
Step 7: Integrate Renewable Energy.
The new key performance indicator (KPI), or building performance metric that is going to matter in the future is watts per square foot. Balancing the cost of renewable energy strategies, such as photovoltaic panels, with energy-saving practices is the key to meeting performance goals while staying within the budget. For example, a simple change to lower-energy phones deployed at the NREL facility reduced the PV panel budget by $375,000.
Step 8: Follow Through.
Part of the reason that our modeling technologies are ineffective and inaccurate is due to the unpredictability of human occupants, operations and maintenance.
The design needs to be carried out by the construction team as intended. In the same way, the operations and maintenance of the building must follow the design intent in order to realize the performance goals.
About Tom Hootman
Tom Hootman is an architect and author with an expertise in innovative sustainable design. Tom possesses strong design and technical skills and is an effective integrator of holistic sustainable design solutions. He has worked on a wide variety of high performance building projects at variety of scales from interiors-to buildings-to cities. One of Tom’s specialties is the design of net zero energy buildings and communities. He has worked on several net zero energy buildings, campuses and communities including the National Renewable Energy Laboratory’s Research Support Facility. Tom’s new book, “Net Zero Energy Design: A Guide for Commercial Architecture”, published by Wiley in October of 2012, allows him to continue to share his knowledge on net zero energy buildings.
About the Author
Brian L. Hill is the CEO of BLHill Inc., a consulting firm that helps buildings and businesses achieve more from less. He is also the editor of AECforensics.com, a digital magazine that explores the trends impacting quality and risk management in the built environment. In addition, Brian is co-chair of the San Diego Green Building Council's marketing committee, and is a volunteer with the ongoing SDGBC Green Assistance Program.