by Julia Nugent
Once considered technically infeasible and cost prohibitive, a Zero Net Energy (ZNE) public school is now within reach for most school districts. The new Annie E. Fales Elementary School in Westborough, Mass. pushes this goal even further. It is projected to be one of the first Positive Net Energy schools (PNE) in New England, producing 10% more energy than required to operate the school itself. With the school now in construction and slated to open next fall, a few key lessons are worth sharing for other teams seeking ZNE success.
Select the Right Team
Zero Net Energy initiatives require early, informed expertise and dialogue across multiple disciplines. Siloed design efforts just will not work, as an energy conservation approach that is optimal for one aspect of the building may be detrimental to the requirements of another. The collaborative effort for Fales included the architect, mechanical engineer, renewable energy consultants, energy modeler, and construction manager working together to define challenges, discuss trade-offs, and come up with a holistic solution.
For Fales, more than 30% of the energy performance savings were realized before or during the schematic design phase, through analysis and consensus decisions about the building’s siting, shape, and basic mechanical and envelope systems. Fine-tuning the design in later stages moved the dial further, but the range of options to reduce energy diminish as the design progresses. In other words, the commitment to pursue a ZNE building needs to take place during schematic design at the latest.
Set Shared, Clear Goals
As leadership guru Peter Drucker once said, “The best way to predict the future is to create it.” Establishing purposeful and attainable strategic ZNE goals at the outset of the project gave the Fales team a clear road map for decisions and became the basis for community dialog and consensus building. One key energy performance goal was the building’s target Energy Use Intensity (EUI), the amount of energy per square foot needed to operate the building over the course of a year (measured as kBTU/sf/yr). At the Fales School, we set an ambitious EUI goal of 25; projected performance is currently tracking slightly better than the original target.
Factor Utility Savings into Project Financing
A second, however no less important, goal for Westborough was to achieve Zero Net Energy use without relying on increasing property tax revenue to pay for it. Yes, the energy savings provisions increased the construction cost of the new Fales School, which in turn increased the annual municipal bond payment by $200,000. However, taking the older, energy hog school off-line will save the town roughly $200,000 per year in utility costs. The new Fales School will have no utility bills for the life of the building, and the 10% excess energy produced will be credited toward energy consumption at other town schools. The bottom line is that the annual utility savings entirely offset the excess annual bond payment.
The shift in affordability for Zero Net Energy comes at an opportune time. As the consequences and cost of climate change come into closer view, our clients want to contribute to the solution by pursuing low-carbon, highly sustainable school projects for their community.
Julia Nugent is a principal with HMFH Architects, a Cambridge-based, women-owned design firm.