Page 133 - Zero Net Energy Case Study Buildings-Volume 1

OBSERVATIONS ZERO NET ENERGY CASE STUDY BUILDINGS, VOL. 1
packages with this type of functionality can be an important and effective key to successful monitoring and reporting of energy use and production data for all buildings. To a large degree, it will also make building monitor- ing and maintenance less of a burden for an owner’s maintenance and operation staff, providing exactly that desired situation of having easily “ac- tionable” information for the normal type of building manager.
Final Observations: Standard Reporting of Energy-Use and Production Data
ZNE buildings can rightfully claim that level of performance only if the occupied completed build- ing actually performs at a ZNE level as confirmed by actual energy use and production data. Although definitions vary, as described in the Introduction section of this monograph, all defini- tions view ZNE is an annual metric; therefore, performance data from a stable 12-month post- occupancy time period is required.
The building’s performance necessarily changes to some degree as it ages—changes in oc- cupancy patterns can cause large changes in energy use, as can weather variability from year to year. Over time, the building shell and building systems may get modified, affecting energy use. Some of the case studies show that attention to building performance in the first year after occupancy can actually improve performance significantly--not a surprise since buildings and building systems rarely operate perfectly from day one. The general observation is that correctly measuring the first year’s performance from the beginning of occupancy is critical to tuning the building so that ZNE operation is actually achieved.
As ZNE performance becomes integrated into California’s building code (and possibly into codes in other states), there will be a growing need to have a standard method of reporting perfor- mance. This is a developing area of work that warrants attention. Building code systems and metrics for analysis and compliance will continue to reside at the state level. However, a stan- dardized system for reporting and/or rating building post-construction performance that is con- sistent nationally (or even internationally) should be considered, including the following factors:
• Reasonable accounting for source energy impacts and greenhouse gas (GHG) emis- sions (which vary widely on a both a regional and seasonal basis);
• Allowances for renewable energy procurement for individual buildings where it is not feasible to locate a sufficient amount of renewable energy production at the building site to fully offset the consumption of the building;
• Emphasis in design on “efficiency first” measures (to avoid oversizing the renewable energy production systems, usually the most expensive component system of a ZNE building);
• Provisions accommodating multi-building developments (e.g., residential subdivisions or campus-style mixed-use developments) that aspire to ZNE at the campus or district level.
Beyond reporting or rating systems, full-scale ZNE certification programs warrant consideration. There are several fledgling systems in the market today (the Living Building Challenge and Earth Advantage’s “Net Zero” certification come to mind). Acceptance and deployment of such sys- tems at scale (similar to the current industry position of LEEDTM), with provisions to incorporate and address substantial regional differences in climate, building practices, consumer prefer- ences, utility grid fuel mix–among several issues–is likely to remain a challenge. Implicit within the concept of certification is the sustained performance of the building over time, through some form of “re-certification,” so that progress continues toward lower greenhouse gas emissions.
Zero Net Energy Case Study Buildings: Volume 1
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