Using the optional steps of eco-indicator 99 to evaluate the operational energy consumption in lifecycle assessment value choices

For environmental evaluation of building operational energy, greenhouse and acidic gases are typically used as appropriate measures. This approach can lead to the loss of additional information concerning other carbon fuel-relevant impacts, such as carcinogenic substances, fossil fuels, and land users. The objective of this study is to analyze three different environmental levels of evaluation: (1) carbon dioxide (CO2) emission (inventory), (2) environmental impacts (midpoint), and (3) environmental damage (endpoint). A simple building module (3×4×3m) facing east, north, south, and west was studied. Eco-Indicator 99 (EI99), a comprehensive damage-oriented lifecycle impact assessment method, was used. Coal was the primary fuel used for electricity production. For each of the three evaluations, an unpaired two-tailed t-test was used to determine the differences between all pairings of the module in the four cardinal orientations. On the basis of inventory and midpoint evaluations, separate optimization of building technology variables is required for each of the cardinal directions; these results were not confirmed by endpoint evaluation. The study informs designers regarding the appropriateness of midpoint evaluation of EI99 (in addition to the CO2 measure) and the need for operational energy consumption to be evaluated from an environmental point of view.