Exterior of Rocky mountain Institute building during winter.
Technical Summary

Net-Zero Buildings

Project Drawdown defines net-zero buildings as: new buildings that utilize high-efficiency building solutions and on-site renewable energy systems to consume zero energy from utility-scale sources and produce net zero carbon emissions on an annual basis. This solution replaces conventional building practices and energy consumption.

“Net zero” refers to new buildings which are either “net zero energy” or “net zero carbon.” Net zero energy buildings are energy-efficient and consume zero energy from utility-scale sources on an annual basis because all the power the building needs is generated through on-site renewable energy. Net zero carbon buildings produce net zero carbon emissions on an annual basis. The definition of zero carbon varies across countries and may include an element of carbon offsetting. For the purposes of this analysis, net zero buildings are considered as new net zero energy buildings.

Methodology

Net zero buildings encompasses several solutions in the Buildings and Energy Sectors that have been modeled individually by Project Drawdown. Net zero buildings can involve all Drawdown solutions modeled, including the installation of better insulation, high performance windows, more efficient lighting, heat pumps, efficient water heating, optimized building system controls, distributed renewable energy systems, etc.[1] Since these solutions were modeled separately, net zero buildings were not modeled independently in order to avoid double-counting.

Results

The emissions and financial impacts of net zero buildings are included in individual solutions in order to avoid double-counting. For more information, see the Sector Summary: Buildings link below.

In order to assess the overall potential of net zero buildings, however, estimates were made based on several future adoption cases derived from the American Institute of Architecture 2030 Challenge framework targets, LEED Platinum building adoptions as a proxy for net zero buildings, and New Building Institute (NBI) current adoption data and growth rates for net zero buildings projects. The potential emissions reduction impacts ranged from 5 to 32 gigatons of carbon dioxide-equivalent, depending on the adoption rate society chooses to implement. If net zero buildings adoption is projected based on using the NBI data, an estimated 9.7 percent of new buildings could be net zero by 2050, with a cumulative emissions reduction of 7.1 gigatons of carbon dioxide-equivalent.

Discussion

The building industry has the potential to have a large impact on drawing down greenhouse gas emissions. There are many different energy efficiency strategies to reduce the impact of buildings. In addition to this, on-site energy generation takes buildings a step further to reduce their impacts. The ideal solution combines both of these strategies with buildings generating as much renewable energy as they consume on an annual basis. This is the essential concept of net zero buildings. In this way, net zero buildings combine many other Drawdown solutions into one elegant concept for humans to strive towards.

In practice, net zero buildings help drive design teams and owners to design and make investments in energy conservation measures and on-site energy generation. The projections of performance are based on a number of factors that could change significantly based on the decisions made by society. For example, if energy efficiency and production along with polluting greenhouse gases were properly priced, the adoption rate of net zero buildings would be much higher. It is plausible that most new buildings could achieve net zero status now if society priced the driving factors around them properly.  

 

[1] Net zero buildings comprise some undefined combination of solutions relevant to the particular characteristics of the building in question in order to achieve net zero status.