Inventory Analysis

• The inventory analysis aims to give an overview of the (most important) material and energy flows concerning the university and its buildings. Only then are the specific measures taken in the individual buildings or environmental areas (top-down procedure). The advantage of the top-down as opposed to the bottom-up procedure, where individual buildings are first investigated in depth and the results are then adjusted to the whole university, is that the evaluator does not get bogged down with too much detail, thus forgetting the overall objective.
• Another objective was not just to consider the direct influence of the university, but also to include the material and energy flows that occur before and after their actual consumption. For electricity consumption, for example, this means the chain from the extraction of the raw material via the power stations to its delivery to the university. The aim of this is to include processes that hardly affect the direct running of the university, but the manufacture or disposal of which make a great environmental impact. The omission of these would falsify the comprehensive balance. The inventory analysis can therefore be split into two separate balances: the core and the complementary balances. According to the Swiss method "Ökobilanzen für Unternehmen" (Ecobalances for companies) the core balance includes those processes that occur in the company itself (e.g. energy supply or waste disposal). All other areas belong to the complementary balance (e.g. company commuter travel, sewage treatment) (Siegenthaler 1994).
• Finally, special attention should be paid to the university's CO₂ emissions. With regard to the CO₂ reduction target of the federal government (a 25% reduction by the year 2005 in relation to 1990) and the decision of the City of Osnabrück to reduce its CO₂ emissions (a reduction of 50% by the year 2010 in relation to 1987), the University is also obliged to reduce its CO₂ emissions. The aim was therefore to identify the CO₂ emissions on the university scale, and for each separate building. Besides the first two objectives, which are the prerequisite for an exact audit of CO₂ emissions, the (energy-related) emissions are to traced back to the individual buildings, so that a table of CO₂ emitters can be drawn up. Moreover, it should be possible to compare CO₂ emissions related to energy, traffic and (waste) water.

Data from 1996 were generally used for the overall balance. The areas of energy, traffic, water and waste water were modelled using the ecobalance software Umberto^®, an interactive tool developed by the Institute of Energy and Environmental Research (IFEU) in Heidelberg and the Institute of Environmental Computer Sciences (IFU) in Hamburg (Häuslein und Hedemann 1995). The other areas were compiled using Excel^® tables.

Impact Assessment