It may seem pie-in-the-sky now, but in the not-too-distant future, net-zero energy buildings will be the standard, rather than the exception. Verified net-zero buildings currently represent less than 1 percent of all commercial buildings according to data from the World Green Building Council. But that number is increasingly rapidly – as much as 50 percent every two years, according to New Buildings Institute data. In the U.S., the number of net-zero buildings is approach 1,000 with more than 75 million square feet of space, though counting the exact number is difficult due to different definitions of what net-zero energy really means.
Dozens of state and local governments have made pledges to reduce emissions and cut energy use to net zero within the next 10 to 15 years. Last year, the Biden Administration announced a plan to make all federal facilities net-zero emissions by 2045. And that’s where the notion of different definitions of “net zero” comes into play. A net zero emissions building is different than a net zero energy building, and both are different than a carbon neutral building or organization. Facility managers need to be very careful about how they’re using these terms to define their buildings.
The International Living Future Institute (ILFI) is one of the organizations that has been at the forefront of not only defining these terms but also creating certification systems to verify net-zero energy buildings. The organization’s signature rating system is called the Living Building Challenge, and is often recognized as the most stringent (and most difficult to achieve) sustainability rating system. ILFI though also has created two certifications – Zero Energy Certification and Zero Carbon Certification – that help delineate the difference between these terms that are often erroneously used interchangeably.
We recently spoke with Jessica Bristow, ILFI’s director of the Living Building Challenge, and Kathleen Smith, ILFI’s vice president of programs and innovation about net-zero energy buildings, why it’s so crucial that these types of buildings scale more quickly, and how net-zero energy is a component of full-building sustainability strategies.
FacilitiesNet: Why must net-zero energy commercial buildings be the future of buildings?
Jessica Bristow and Kathleen Smith: The United Nations’ International Panel on Climate Change (IPCC) synthesis report published in March 2023 summarizes almost a decade of the latest climate science into an urgent call to action. The report shows that global greenhouse gas emissions continue to increase despite international pledges, and that we are almost out of time to limit warming to 1.5 degrees Celsius and avoid catastrophic and irreversible global impacts. Buildings play a big role in the climate crisis and are therefore critical in the solution. Buildings are responsible for 40 percent of global carbon emissions due to the energy required to construct and operate them and are responsible for even more carbon emissions when we account for the manufacturing of building materials.
It is critical that all new construction (where the opportunities are abundant for reducing energy use) operate as net zero energy, which means they produce as much energy as they consume on a net annual basis. It is equally critical to vastly reduce the energy consumed by existing buildings through envelope and system retrofits and changes in building operations and occupant behavior. Existing buildings should seek ways to generate the energy needed to operate through renewable energy onsite, for example by using photovoltaic panels. Because of the additional constraints in adapting existing buildings, these projects may need to rely more on carbon offsets, scale jumping (with key systems offsite), or handprinting (acknowledging beneficial changes to environmental and social impacts) to reach the goal of net-zero energy.
Beyond the undeniable urgency of the climate crises and the associated ethical responsibility, there are many other environmental, social, and economic reasons for the commercial real estate market to make net zero commercial buildings the future of buildings. Some of these reasons include:
The time to build a net-zero future is now. If we’re to have any hope of curbing greenhouse gas emissions and mitigating the impacts of the climate crisis, net-zero energy and net-zero carbon buildings need to be standard practice.
FacilitiesNet: Please explain the specific difference between zero energy buildings and zero carbon buildings -- how do your certification programs deal with these differences?
Jessica Bristow and Kathleen Smith: Operational carbon refers to the greenhouse gas emissions associated with the operational energy use of a building, or life cycle stage (B6 as defined by EN 15798). Operational carbon or energy is the total from all energy sources used during the service life of a building to power base systems, such as lighting, heating, cooling, ventilation, and plugs and process loads (PPLs). Embodied carbon refers to the greenhouse gas emissions associated with the production of the building. This includes the extraction and production of materials used during construction and their transportation in addition to the carbon released by plants and machinery throughout the building process itself. In the case of rebuilds, demolition adds to the embodied carbon of a site.
ILFI’s Zero Energy Program allows projects to demonstrate that the building is truly operating as claimed, harnessing energy from the sun, wind, or earth to produce net annual energy demand. At its core, a zero energy building (verified by a third-party after a 12-month performance period) must renewably generate at least an equal amount of energy as it uses for building operations. This is typically accomplished through an extremely energy-efficient building, careful operational protocols, and on-site or off-site renewable energy.
ILFI’s Zero Carbon Program provides a vision for a future of carbon positive buildings that reverse the effects of climate change. By addressing both operational and embodied carbon emissions, Zero Carbon Certification offers organizations a valuable tool to demonstrate credible climate action. Zero Carbon certified buildings are verified by a third-party after a 12-month performance period to be energy efficient, combustion free (or actively phasing out combustion), and powered by renewals.
In essence, ILFI’s Zero Energy program and the term zero energy only refers to a building's operational carbon. While ILFI’s Zero Carbon program and the term zero carbon refers to a building's operational and embodied carbon, although this varies across other programs and certifications. Ultimately, both have tremendous impact on global climate issues, and thus both must be addressed in both new construction and existing buildings. It should be noted that by reusing an existing building instead of building new, commercial real estate owners are greatly reducing the embodied carbon impacts of their projects.
Together, zero energy and carbon have very effectively widened the vision and understanding of climate-positive buildings, expanding the audience for high-performing and integrated buildings beyond those deeply dedicated to energy-specific and technical solutions. Moving forward, zero energy and carbon must focus on shifting the approach from one of autonomous buildings toward an energy ecosystem of buildings, transportation, industry, and renewable generation, sharing thermal and electrical resources that are generated in planet positive ways.
FacilitiesNet: How does net zero energy fit into the concept of whole-building sustainability as specified in rating systems like the Living Building Challenge?
Jessica Bristow and Kathleen Smith: ILFI sees whole-building sustainability as the ‘Living Future’: our vision is a society that is socially just, culturally rich, and ecologically restorative. A critical element of the Living Future is the built environment, and a critical element of our built environment is reducing emissions impacts and reaching zero energy. Today, the built environment is one of the main contributors to our existential threats. Buildings are responsible for 40 percent of global carbon emissions due to the energy required to construct and operate them (in fact they are responsible for much more carbon emissions when we account for the manufacturing of building materials).
This energy- and emissions-focused component is a big piece of the puzzle, and is a tangible and impactable area in which we can truly make a difference in reaching climate goals and reversing human impacts. ILFI continues to be a leader in and maintains an eye on fair carbon accounting and honest, impactful policies for our Living Building Challenge Energy Petal, Zero Carbon, and Zero Energy standards and certifications.
However, at ILFI, our energy and carbon goals are one integrated component within a bigger regenerative ecosystem. The Living Building Challenge drives change across seven performance areas, or Petals: Place, Materials, Water, Equity, Energy, Beauty, and Health + Happiness. In addition to contributing to global carbon emissions, buildings are a major contributor to economic health and in maintaining household and community resilience in times of crisis. They also have a massive impact on human health and wellbeing. This impact can be positive when care is given to ensure high levels of indoor air quality, daylight, views, access to nature, healthy materials, and beauty. The labor of building and maintaining our built world represents an enormous workforce. Throughout the life of a building, many people are engaged from manufacturing workers, to architects and engineers to end users and neighbors in the community. Regenerative buildings consider the economic, environmental, and social aspects to all across this life cycle equally and holistically.
The goal of the Living Building Challenge is to build and maintain buildings that are healthy and resilient, that create and sustain great jobs, that are ecologically regenerative, and are the infrastructure and inspiration for our future. With every act of design and construction or renovation, we can make the site, community, and world a better place.
Greg Zimmerman is senior contributor editor for the facility group, which including FacilitiesNet.com and Building Operating Management magazine. He has more than 19 years’ experience writing about facility issues.
