Re(de)fining Net Zero Energy Definitions: Renewable Emergy Balance (REB)

Currently, buildings are design for optimal operational energy use and not for its embodied energy content. This may be a failing strategy for the larger sustainability of buildings since operational energy is only a portion of all the energies that have been used for the design, construction, operation, and demolition of the building. More importantly, the notion that raw materials for building construction are plentiful and can be extracted “at will” from Earth’s geobiosphere, and that these materials do not undergo any degradation or related deterioration in performance while in use is alarming and entirely inaccurate!

For these reasons, a particular building, like an organism or an ecosystem, must seek self-sustenance for that design to prevail in competition with other building designs in a time with limited availability of energy and materials. My research in the development of Renewable Emergy Balance helps to maximize renewable resource use through emergy analysis to close the gap between current approaches to environmental building design and the over-arching goal of creating buildings that contribute to a sustainable relationship between human activities and the geobiosphere. This tool helps maximize renewable resource use through disinvestment of all non-renewable resources that may be substituted with renewable resources. Such buildings attain a high standing by optimizing building construction over their entire life-span from formation-extraction-manufacturing to maintenance and operation.

Figure (left: Identification of the maximum renewable emergy potential for moving toward a Renewable Emergy Balance. The top graph is the cumulative non-renewable resource use over the building’s life-time. The lower histogram shows the largest renewable emergy potential that exists in each stage of the building’s life-time. Figure (right): Systems diagram of building environmental design showing energy pathways.

The following lists the major contributions that this research made to the environmental accounting of buildings.

• Development of a method to assess the Renewable Emergy Balance of a building. Renewable Emergy Balance buildings  promote a high standard of sustainability by optimizing the use of renewable energy and materials over the entire life-cycle of the building from formation-extraction-manufacturing to maintenance and operation.
• Maximize renewable resource use through progressive disinvestment of all non-renewable resources that may be substituted with renewable resources, thereby contributing to the overall sustainability of the geobiosphere.
• Development of methods to determine the maximum renewable emergy potential for buildings. This limit can be used to integrate renewable resources over the life-time of the building to achieve a Renewable Emergy Balance.
• Alleviate any ambiguity related to the limit or benchmark that is set to achieve higher levels of sustainability.

The journal publication published in one of the reputed international journals in the field of building and environment has been cited more than 38 times, since 2012, wherein over 90% of the authors who cited are outside the US. I have presented this research contribution internationally (Australia, Berlin, India) and in the US including the US EPA office in Narrangansett, MA.