The 332 buildings verified as or on their way to achieving net zero energy certification represent a 74% increase since the last count in late 2015, according to a report by the New Buildings Institute (NBI).
By the end of 2016, the organization had verified an additional 20 projects as having achieved net zero energy consumption for at least one full year for a total of 53 – up from 33 projects in 2014, NBI notes. Performance data for all certified net zero energy buildings is verified to ensure that all energy consumed by the facility is balanced by on-site renewable energy generation every year. More than 60% of the net zero energy buildings verified in 2016 also earned LEED certification.
Among the buildings on the net zero registry is the Santa Fe Springs office of the California State Lottery, which tested ultra-efficient design choices in a 2015 renovation in anticipation of a state executive order mandating net zero energy for all new and renovated state facilities starting in 2025.
The deep retrofit strategies used for the 12,840-square-foot warehouse included a rooftop PV system, high R-value wall and ceiling insulation, and intelligent HVAC with a single-zone VAV system. Daylight modeling helped the design team determine how to lower lighting power density, and a plug load study offered a baseline for reducing occupant power usage. The building also features dashboards that encourage energy-efficient behavior and allow occupants to provide feedback.
The cost of the retrofit process (excluding purchasing the building) totaled $5.7 million, with about $5 million used for construction, roughly $700,000 more than it would have cost to just meet code. Adding PV panels accounted for $240,000 of that increase, or about 4% of the total. However, the aggressive efficiency approaches saved $48,000 in the cost of renewables, according to post-construction analysis. The lottery office is currently classified as “emerging net zero energy” and has so far achieved a net EUI of -0.1 by generating 22.2 kBTU per square foot per year in renewable energy, just over the building’s EUI of 22.1.