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Building energy efficiency policies are an important tool in addressing energy and climate policies. There has been tremendous technical and policy activity in recent years aimed toward improving building energy performance, with a focus on getting to very low energy buildings and targeting “zero” energy or emissions buildings. A variety of governments have established ambitious, and sometimes aspirational, policies and targets for zero energy buildings (ZEBs) to become standard or commonplace. This report, intended for energy and buildings policy-makers, provides an overview of relevant definitions covering all types of zero energy or emissions buildings, regulatory policies aimed to push those standards, implementation approaches and market progress where available, and lessons learned.
Definitions that appear quite similar can actually have very different impacts, and policy ramifications. There are a variety of key issues among the definitions, including which energy uses are regulated, the boundaries of energy consumption and production, and whether off-site renewable energy purchases can be counted; the choices among these issues can be quite significant.
Many ZEB policies begin with a quite ambitious target several years away, to allow time for capacity building and experience in understanding what is needed to get the major energy reductions. In most of the early cases where these targets had been set for 2020 or earlier, it is not clear whether the established goals will be met (most experts are very skeptical about all new buildings meeting established goals) but having aspirational targets has made a very significant difference in accelerating the penetration of ZE or very low energy buildings, relative to other regions or jurisdictions without such ambitious policies. Having these targets in place has proved to set a ‘future-proof’ vision for the sector and mobilize stakeholders accordingly.
Concerns have been raised about a performance gap, where buildings are designed to be ZEB, but in actual operation, consume significantly more than had been predicted. The performance gap issue is not unique to ZEBs, but needs careful attention to ensure that the ZEB expectations are met.
The policies and incentives supporting ZEBs matter. Most of the growth and progress have been seen in areas where there is strong supranational, national, state/provincial or local support, including access to financing; understanding how the progress continues in these leading areas will be important in the coming years.
There seems to an emerging trend to use zero carbon instead of zero energy as the metric, and as noted earlier, there can be subtle issues between the two metrics that are significant. As zero carbon grows in uptake, additional research and quantitative analysis will be required to understand the differing impacts of the two standards, interactions between energy and carbon as the metric, and how existing policies may need to be adjusted.
In the coming years, it will be important to prove the ZEB concept after large numbers of buildings have been occupied for a period of time—and to communicate that effectively to industry associations, governments and the public—to enable future growth and progress.