While programs like the U.S. EPA’s ENERGYSTAR or the U.S. Green Building Council’s LEED rating system encourage and reward energy efficiency, it makes sense that the ultimate energy-efficiency objective is to achieve zero-energy status.
It might seem far-fetched, but there are 21 buildings already doing this in the United States; 78 others already have the capability to do so, or are well on their way. Zero-energy building projects are being completed all across the country in a variety of climates, from California to Florida toVermont, and several other states in between (like Ohio, Missouri, and Minnesota).
Zero-energy buildings (ZEBs) are so energy-efficient that their annual energy balance (their consumption minus the electricity they generate) equals zero or less than zero. In the long run, these facilities don’t need energy from nonrenewable sources like utility electricity. Although the buildings might pull from the grid in some situations (depending on demand and time of year), they also supply excess power back to the grid during other times of the year via the renewable energy being generated onsite through wind, solar, or geothermal strategies.
So how are these buildings actually achieving zero-energy status? Although their purposes are very different (from retail to education to office space), there are a few characteristics they share:
- Square footage. Most ZEBs aren’t very expansive (under 20,000 square feet) and are only a story or two high.
- Building orientation and window placement. ZEBs are planned and built on the site to maximize exposure to shading and natural ventilation, and passive solar and daylighting strategies.
- Whole building design processes. Starting at the very beginning of the design process, the project team for a ZEB is made up of a variety of experts who make decisions together from start to finish (interior designers, mechanical/electrical/plumbing engineers, environmental consultants, civil engineers, etc.).
- Small plug loads. With every equipment purchase, from coffeemakers to copiers to computer monitors; all uses of energy are carefully considered. All equipment selected must be able to be turned off at night.
- Exposed concrete floors and masonry walls that keep temperatures at moderate levels all day/night long.
- Occupancy and daylight sensors to control the use of artificial light.
- Monitoring of mechanical systems so facilities managers know immediately if equipment isn’t functioning properly or is consuming too much energy.
To learn more about zero-energy buildings and the U.S. Department of Energy’s Commercial Building Initiative, which supports ZEBs, read our previous blog post on the topic.
Is zero-energy status something you’d like to achieve with your facility? Why or why not? Do you think a net-zero building is achievable?