Climate Neutral Campus Key Terms and Definitions

The term climate neutral evolved along with net zero and a number of other "green" labels. Using consistent terminology is important because using different terms for the same concept or category leads to confusion and disparate measurements for energy consumption and emissions. Consistency and accuracy in these areas lets research campuses know exactly how close they are to climate neutrality.

The following are key terms and definitions surrounding climate-neutral research campuses:

  • Climate-neutral campus: A campus has no net climate impact resulting from carbon or other greenhouse gases. This can be best achieved through a hierarchy of actions that include aggressive reduction of energy consumption, followed by conversion to low or no impact energy sources, and finally through carbon offsets.

    The American College and University Presidents Climate Commitment defines climate neutrality as having no net carbon (greenhouse gas) emissions. This is to be achieved by "minimizing carbon emissions as much as possible, and using carbon offsets or other measures to mitigate the remaining emissions."

  • Net-zero site energy: The amount of fossil-fuel generated energy consumed on-site is balanced by the same amount of renewable energy produced on-site.

  • Net-zero source energy: This is similar to net-zero site energy, but goes a step further by including energy required to deliver both electricity and fuels. This energy expenditure must also be balanced by renewable energy production on-site.

  • Net-zero energy costs: The amount of money the building owner pays the utility for electricity, fuels, and reliable services is equal to the amount of money the utility pays the owner for renewable energy generation.

  • Net-zero energy emissions: A net-zero emissions building or community produces and uses at least as much emissions-free renewable energy as it uses from emissions-producing energy sources. Emissions usually refer to emissions regulated by the U.S. Environmental Protection Agency (EPA), including carbon, nitrous oxides (NOx) and sulfur oxides (SOx).

    In addition, other sources of greenhouse gas emissions exist. These emissions derive from normal operations of power equipment, escape of refrigerant gases from air conditioners, decomposition of organic matter in agriculture, and other activities. The World Resources Institute has established protocols for how to account for these emissions.

In addition to these definitions, NREL released a technical report on the definition of zero-energy buildings: