Raw materialsEnergy media

Figure 5.3 Life cycle assessment. Source: adapted from Saling et al. [22].

Life cycle assessment

From the cradle to the grave

Eco-efficiency

From the cradle of the works gate

Figure 5.4 Eco-efficiency analysis includes life cycle assessment and environmental profile. Source: adapted from Salingetal. [22].

Environmental profile

From the cradle to the grave and costs

Life cycle assessment

From the cradle to the grave

Eco-efficiency

From the cradle of the works gate

Figure 5.4 Eco-efficiency analysis includes life cycle assessment and environmental profile. Source: adapted from Salingetal. [22].

First, the environmental impact is described based on six categories:

1. Raw material consumption.

2. Energy consumption.

4. Air and water emissions and disposal methods.

5. Potential toxicity.

6. Potential risks.

Energy consumption is determined over the entire life cycle and describes the consumption of primary energy. Fossil energy media are included before production and renewable energy media before harvest or use. This captures conversion losses from electricity and steam generation.

Emission values are initially calculated separately as air, water and soil emissions (waste). The calculation includes not only values, for example, from electricity and steam production and transport but also values directly from the processes. The individual values are subsequently aggregated via a weighting scheme to form the overall value for the emissions. Air emissions considered were CO2, SO2, NOx, CH4, hydrocarbons (HC), halogen HC, NH3, N2O, HCl and HF. These are lumped into four impact categories:

1. Global warming potential (GWP).

2. Ozone depletion potential (ODP).

3. Photochemical ozone creation potential (POCP).

4. Acidification potential (AP).

For the inventory of emissions to water, the following aspects are considered: COD (chemical oxygen demand), BOD (biological oxygen demand), N-tot (total nitrogen), NH4 + (ammonium), PO43~ (phosphate), AOX (adsorbable organic halogen), heavy metals (HMs), hydrocarbons (HCs), SO42~ (sulfate) and Cl_ (chloride).

The results of the inventory on solid wastes are combined to form three waste categories: special wastes, wastes resembling domestic refuse and building rubble/ gangue material.

Under raw material consumption, the mass of raw materials needed by the corresponding process is determined first. The individual materials are weighted according to their reserves. The toxicity potential is calculated using the classifications for hazardous materials under EU law. The abuse and risk potential reflects the dangers of accidents in the manufacture, use and recycling of the product. The approach adopted is similar to a risk assessment in the case of plant safety in which the probability of occurrence and the level of damage are estimated. Values used for the individual products are only comparative and not absolute.

The different categories, after normalization, are then aggregated using weighting factors. For more details on the estimations of the different categories and methods of their aggregation, reference could be made to the work of Saling et al. [22] and to the BASF web site of eco-efficient analysis (http://www.corporate.basf.com/en/ sustainability).

The results can also be viewed using a special plot called the environmental fingerprint. Figure 5.5 reports an example taken from the work of Saling et al. [22] of the evaluation of different alternatives in the use of indigo, the dye that is used for coloring in blue the jeans. Clearly, the electrochemical variant is the most advantageous alternative in all categories. With the exception of risk potential, the least favorable variant on all criteria is indigo powder from plants.

Estimating the total costs it is then possible to plot normalized cost versus environmental impact and thus select the most favorable alternatives that are located top right in the plot (Figure 5.6). The distance of the individual alternatives to the plot diagonal is a measure of the respective eco-efficiency.

Energy consumption

Materials consumption

Energy consumption

Materials consumption

Indigo powder

Indigo granules

Emissions

Figure 5.5 Environmental fingerprint by BASF of indigo dye (dyeing process only). Source: adapted from Saling et al. [22].

Biotechnological production

Produced electrochemically

Indigo powder

Indigo granules

Emissions

Risk potential

Toxicity potential

Figure 5.5 Environmental fingerprint by BASF of indigo dye (dyeing process only). Source: adapted from Saling et al. [22].

Total cost (normalized) Figure 5.6 Eco-efficiency versus total cost (portfolio plot) for the indigo study (dyeing process only). Source: adapted from Saling et al. [22].

Total cost (normalized) Figure 5.6 Eco-efficiency versus total cost (portfolio plot) for the indigo study (dyeing process only). Source: adapted from Saling et al. [22].

The value of the eco-efficiency analysis tool lies also in the recognition of dominant influences and in the illustration of "what if ... ?" scenarios. It is also possible to perform sensitivity analyses in every project. Not only the assumptions made, but also the system boundaries and the societal weighting factors, are varied and checked within realistic ranges.

Eco-efficiency analysis results make it also possible to identify weaknesses in products, processes and overall systems over the entire life cycle. This makes it possible to identify factors whose optimization would result in distinct improvements in the overall position of an alternative under consideration. From another point of view, it is possible to use this tool to develop marketing strategies with a joined-up focus and identify synergistic impacts in the overall process.

Eco-efficiency analysis can be expanded to include an assessment of the social dimension of the sustainability-analysis (SEEbalance methodology) [24]. In this way, it is possible to obtain an integrated assessment of economic, ecological and social aspects of products and processes, and introduce the ecotoxicity evaluation model as a standard tool to the environmental dimension of the analysis.

Although providing only comparative and not absolute values, the methodology of eco-efficiency is very useful for an evaluation of process alternatives. In Chapter 1 (Section 1.6.1), Table 1.10 summarizes the results ofa study by EuropaBio to evaluate the contribution of biotechnologies to sustainability. One of the cited examples is the synthesis of vitamin B2, an essential nutrient found in meat, dairy foods, plant foods and corn products and which is required by the body to break down food components, maintain tissue and absorb other nutrients. Using the eco-efficiency and, particularly, the portfolio plot it is possible to further demonstrate the benefits

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4-1

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K arabonate

Ca arabjonate

Ca ribonate

Ribonolactone

Ribítylxylídine

Phenylazo-RX

Vitamin B,

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Fermentation

Fermentation

X • High eco-efficiency

Chemical process

Low # eco-efficiency

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