Show Me The Numbers: Getting To Net Zero

By: Michael Murray| Past Issue – Sustainability|

Net zero energy buildings – buildings designed to generate as much energy as is consumed over the course of a year – have recently gained important footholds in architectural practice, owners’ expectations and public policy. In the last five years, the 2030 Challenge was formally adopted by the American Institute of Architects; the first ever set of buildings was certified as net zero under the Living Building Challenge standard; an Executive Order from President Obama required the U.S. General Services Administration to make all new construction projects net zero energy beginning in 2030; and net zero energy construction became the official policy of the state of California beginning in 2020. Net zero policies mean that designing, constructing and operating buildings are going to become professionally demanding in short order for architects, engineers and facility managers. It also means that there will be significant changes taking place in the field of architecture.

The changes I see on the horizon are both daunting and exciting because it requires architects to redefine their role and responsibilities. The first change I see is that buildings, and their designers, will be evaluated with a new, quantitative emphasis. Architecture, a field not generally accustomed to being judged on quantitative terms, will need to redefine its success criteria to include the energy balance between production and consumption. The green building movement has challenged architects to design for percentage reductions in energy use over a baseline. But net zero energy buildings require much more: a comprehensive accounting of every kilowatt-hour. To start, architects will need to become fluent in benchmarking tools such as U.S. Environmental Protection Agency’s EnergyStar. (EnergyStar has a web-based design feature called Target Finder that calculates the kBTU per square foot per year required to meet certain goals.) Architects will need to know the designed Energy Use Intensity (EUI) and compare it with the kilowatt-hours that can be generated on-site. Adroitness in energy performance numbers will become a professional norm: Failure to know EUIs off the top of an architect’s head will be as embarrassing as, say, forgetting who designed the Louvre.

Second, not only will architects need to think in terms of EUI, but architects will find aesthetic sensibilities falling in importance as a balanced energy budget rises in importance. Different forms might be welcoming or whimsical, but the outcomes of the creative process can only be entertained if the design draws less energy than it produces. With limited time and resources, owners will pay less attention to aesthetic concerns in proportion to their level of commitment to net zero.

Third, the boundaries of responsibility for architects will expand, stretching into the post-occupancy period. To truly reach net zero, architects will need to pay attention to electric and gas meters, facility management practices, and occupant behavior for at least a year after construction is completed. Rather than wiping his or her hands of the project and moving on to the next one, the architect will need to remain engaged with the owner and building occupants because the architect will be responsible, in part, for its operational energy use. Once charged with designing a net-zero building, the architect will share some responsibility in delivering a net-zero building – even after occupancy. One imagines architects reviewing monthly energy performance statements of their portfolio and, as with viewing one’s personal bank account balance, taking remediative actions when the numbers do not meet expectations.

Fourth, our understanding of the role of building occupants in using energy will need to be qualitatively and quantitatively assessed. Lucid’s own research on this topic found that plug loads in modern commercial offices ranged from 30% to 50% of total building electricity usage. (Plug loads are the numerous devices plugged into electrical outlets – computers, office equipment, battery chargers, space heaters, etc.) This means that occupants, and not designers, control a significant percentage of energy used in the building. In fact, in many of Lucid’s customers’ facilities, plug loads as a category exceeded lighting and heating, ventilation and air conditioning (HVAC) loads. As lighting and HVAC have become more efficient, the energy used by occupants can no longer be ignored. With very low-energy buildings, the plug load problem is even more acute: New Buildings Institute has pointed out that plug loads can be 40% to 60% of total electricity use. Architects and their consultants need to engage with their clients on office equipment procurement, information technology policies, and behavioral and cultural norms with regards to energy use.

One Lucid customer illustrates just how much reaching net zero energy hinges on building occupants. DPR Construction, a general contractor with a specialty in green buildings, designed and built a net zero office for their staff in San Diego, California. Several months after construction was completed, the staff, using Lucid’s Building Dashboard to track energy produced from rooftop photovoltaics and energy consumed, noticed that the building was not, in fact, reaching net zero. The night-time baseload was consistently high, even though no one was in the office. The staff began turning off all unnecessary appliances and sending reminders to turn off computers and office equipment at the end of the workday. Their diligence has paid off: as of this writing, the building produced 28% more energy than it has consumed thus far in calendar year 2011.

Performance monitoring and measurement are rapidly becoming requirements for the design professions. LEED, for example, in responding to criticism that it does not sufficiently emphasize energy performance, is considering changes that will push architects even further in this direction. The next version of LEED, currently in draft form, has prerequisites for reporting energy and water consumption to USGBC for five years after construction. LEED 2012 for Existing Buildings Operations & Maintenance requires an EnergyStar score of 75, up from a previous score of 69 in LEED v3. And recertification via LEED-EBOM is going to be emphasized by USGBC as a fundamental part of maintaining its green credential.

LEED is a significant market driver and cannot be ignored. As LEED slowly ratchets up its performance requirements and makes incremental improvements, a growing community of organizations is moving rapidly towards the ultimate goal of net zero. It is only a matter of time before the performance tracking requirements of LEED are made to look unsophisticated in the face of net zero buildings. Prepare to be measured.