Carbon as the New Metric for Measuring Building Performance

By Jeff Stanton, AIA, NCARB, LEED AP

The design of the National Renewable Energy Laboratory’s (NREL) Science & Technology Facility along with on-site generation of renewable energy and purchase of green power has yielded a carbon reduction of 95 percent or 6 lbs/sf/yr. Photo by Bill Timmerman, courtesy of SmithGroup

The stakes are high! There is an increased sense of urgency to address the problem of global climate change. As has been well-documented over the past few years, ever-rising greenhouse gas emissions have been attributed in large part to human activity. The situation was stated by the U.N. Intergovernmental Panel on Climate Change (IPCC) in their Fourth Assessment Report issued in February 2007. In reality, emissions are accelerating at a much faster rate than even the IPCC has predicted over the last eight years.

As documented in the report, there is agreement among the scientific community that a 2o C (3.5o F) rise in temperature constitutes a tipping point where the damages of global warming will be irreversible. This equates to an atmospheric CO2 equivalent concentration of 450 parts per million (ppm). The current CO2 concentration level is around 386 ppm. CO2 represents greater than 75 percent of all greenhouse gas emissions. If we add in all other sources, we may currently be reaching an equivalent CO2 concentration of 430 ppm. As you can see, there isn’t much room, especially considering the CO2 concentration curve is accelerating.

Building Industry
The building industry is a major contributor to the greenhouse gas inventory through both direct (project site) and indirect (source) emissions. Source emissions account for a majority of building sector impacts and are those that are generated elsewhere, mainly by fossil fuel-based power plants, as a consequence of our actions. The Architecture 2030 Challenge has indicated that buildings account for more than 48 percent of all energy consumption and greenhouse gas emissions annually, and consume 76 percent of all electricity produced by power plants. Because we are responsible for creating the built environment, the building industry must take a leadership role in helping to solve this crisis.

New Carbon Economy
There are several options for how best to deal with climate change and the reduction of greenhouse gas emissions. Because carbon dioxide represents a majority of the greenhouse gases, several schemes have been created — Carbon Cap and Trade, Carbon Tax, and other variations — to deal with that element. Cap and Trade is a market-driven system where a central authority sets a limit on emissions as well as a price. The cap total is divided into allowances or permits which are allocated to participating entities based on current emission levels. Every year, the cap and number of allowances is reduced, forcing participants to either cut their emissions or purchase unused permits to offset their pollution.

Proponents believe that these systems will provide a financial incentive for companies to reduce their emissions. Opponents feel that imposing a cost on carbon would translate into higher energy costs. The new administration is taking up this issue currently, but no matter which scheme is implemented, there is a clear sense of urgency if the U.S. — and the world — hopes to affect climate change.

New Direction for Measuring Building Performance
Building performance is often measured in terms of Energy Use Intensity (EUI) in kBTU’s per square foot annually, or Energy Cost Savings in dollars per square foot annually. Even though these metrics are important to evaluate, they do not easily translate to environmental impacts. If we are ever going to bring the discussion to the language of mitigation, we must define a different metric for measuring building performance. I suggest that the common metric should be in terms of carbon reduction per project in pounds (or tons) per square foot annually.

As we move into this new economy, organizations and companies will most likely be required to report their carbon emissions annually and to find ways of reducing their impacts. So why doesn’t the building industry jump on board and start informing building owners of how their buildings are mitigating climate change? Owners will soon demand this as part of their organization’s commitment. Climate change must be addressed in the design and construction of their facilities. Owners will also demand to know what the design and construction industry’s experience and expertise is in addressing climate change when hiring firms.

The stakes are high and we, in the building industry, must be the leaders in providing buildings that succeed in the new carbon economy.

Jeff Stanton, AIA, NCARB, LEED AP, is a vice president and sustainable design leader at SmithGroup’s Phoenix office, as well as serves on the USGBC Arizona Central Branch Governing Council.  He may be reached at jeff.stanton@smithgroup.com. 
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