In order to realize significant decreases in the United States’ dependence on fossil fuels, many commercial buildings must become net-zero energy in the near future. In addition to net-zero energy new construction, many buildings must also be retrofit to be net-zero energy. Compared to new construction, which only represents about two percent of the existing building stock in any given year, retrofitting existing facilities to meet net-zero energy standards presents difficult technical and economical challenges (Brown, Southworth, & Stovall, 2005). Foremost among these challenges are the lack of usable space for renewable energy installations and the cost of both renewable energy systems and energy-efficiency improvement projects.

This paper first discusses a path to net-zero energy for the Akron Zoo campus that may be a model for other commercial facilities. This path includes aggressive energy-efficiency combined with on-site renewable energy installations. Next, the analysis focuses on major implementation constraints, particularly on limited usable space for renewable energy generation. Further, economic comparisons between energy-efficiency and renewable energy are used to determine optimal economic decisions. Next we present analysis of possible energy-efficiency opportunities and how we arrived at unexpected conclusions. Finally, we present conclusions that support the Akron Zoo’s capability to achieve net-zero energy status.