LEED buildings and carbon reduction

LEED buildings and carbon reduction, LEED-certified buildings contribute to climate mitigation in several ways to reduce carbon waste

LEED buildings and carbon reduction

LEED-certified buildings contribute to climate mitigation in several ways:

Use less energy and water: When building projects are rewarded for deeper energy and water efficiency retrofits, there is an opportunity to reduce the consumption of fossil fuel and electricity. Similarly, LEED rewards reductions in water use and the “embodied carbon” used to produce, move and treat that water.
Consider life cycle impacts: LEED encourages life cycle assessment (LCA) of building materials and products, and, in turn, whole buildings. Assessing alternatives based on life cycle GHG is a critical first step to selecting lower-impact approaches and providing market feedback.
Support sustainable strategies: Green buildings provide mechanisms to actively influence inhabitants in ways that support the climate. For example, buildings can create opportunities for more composting and reduced landfill waste and for alternative transportation.
Shrink carbon footprint: LEED rewards thoughtful decisions about building location with credits that encourage connection with transit and amenities, as well as retention and creation of natural vegetated land areas and roofs.

According to a 2018 assessment by the U.S. General Services Administration, its portfolio of high-performing buildings - many of them LEED-certified - used 23% less energy and 28% less water, and they generated 9% less landfill waste than GSA’s legacy stock buildings. Each of these resources has associated GHG emissions, so reducing their use can shrink a building’s total operational GHG footprint.

A study from the University of California at Berkeley for the California Air Resources Board quantified the GHG reductions from non-energy categories for LEED-certified existing buildings in California. The study found that buildings certified under LEED for Operations and Maintenance were associated with 50% less GHG emissions from water use, 48% less GHGs from solid waste and 5% less GHGs from transportation

LEED credit categories address topics such as reduction in energy use, connection with public transportation and the embodied energy associated with materials and water use.

Building operations energy use and source: Credits in the Energy and Atmosphere category not only directly reduce energy use, but they also address systems that rely on carbon-based energy sources and award the use of low-carbon energy sources. LEED also targets the reduction of potent GHGs associated with refrigerants.
Renewables selection: Credits in the Energy and Atmosphere category recognize the diverse contract mechanisms project teams use to procure renewable energy off-site and articulate a hierarchy for renewable energy generation and procurement that rewards selections that are high value. Establishing LEED criteria addressing the age of a renewable energy–generating asset helps to guide project team decision-making and direct investments toward increasing the supply of renewable energy on the grid (versus using existing renewable energy capacity where possible).
Transportation energy use: Credits in the Location and Transportation category enable new buildings to improve land use patterns and position occupants to take advantage of public transportation, which contributes to a reduction of GHG emissions from single-passenger vehicles.
Materials-embodied energy use: Materials and Resources credits address a building's embodied carbon by targeting the energy use and processes required in the extraction, production, transportation, manufacturing, distribution and disposal of materials and products used throughout the entire life cycle of a building.
Water-embodied energy use and source: Water Efficiency credits address the significant use of energy related to the treatment, processing and distribution of water by requiring a reduction of water used. Efficiencies that reduce the use of potable water, and replacing it when possible with nonpotable water sources, will indirectly reduce energy use and help mitigate GHG emissions.
Green infrastructure and siting: Sustainable Sites credits focus on the non-energy-related drivers of climate change, including land use changes, heat island effect and pollution through solutions such as green infrastructure and purposeful decisions on building location and siting.

In addition, LEED v4.1 for Building Design and Construction includes the Optimize Energy Performance credit, which has two metrics: energy cost and GHG reduction. A potential of 18 points may be awarded, based on the sum of points for each metric.