Evaluate product systems

This section describes the final steps to calculate the product systems' emissions and display the results.

Define a Product System Completely

To evaluate a product system (i.e. calculate the emissions) it must first be completely defined. This means

  1. each reference flow is connected to a utilization process. Utilization processes that are not connected to a reference flow will not be considered in the calculation.
  2. all utilization processes are edited according to your specifications./li>
  3. you have entered the correct correct amount of kilometers into the reference flows, that shall be traveled with the respective vehicles. This is important to build and compare mobility chains.

Calculate emissions

When the product system(s) are completely defined you may start the calculation of emissions. This is done by clicking one of the "evaluate" buttons () which can be found in any of the graphics panels. After a short while the results will be displayed graphically in each open graphics panel.

When you click the "evaluate" button, the program will consider all product systems which have an open product system editor, i.e. those that have a tab atop the editor area. Each product system is considered as a unit, i.e. one particular journey. This allows to compare mobility chains:

The sum of the kilometers entered in the reference flows has to be the same in all evaluated product systems. Otherwise a comparison of emissions would not make sense.

Display of results

Emission categories

ECOCLASS shows emissions in three aggregated categories:

  1. CO2 Equivalents (greenhouse effect): This is an aggregate of all emissions that contribute to the anthropogenic greenhouse effect and thereby to climate change, mainly carbon dioxide, methane, laughing gas and halo-carbons. To make these emissions comparable we calculate from their amount and their global warming potentials the amount of CO2 which would yield the same contribution to the greenhouse effect. These "CO2 equivalents" are added and displayed.
  2. SO2 Equivalents ("acid rain"): This is an aggregate of all emissions that contribute to the release of (sulphuric) acid and thereby to acid rain, mainly sulphur dioxide, nitrous oxides, and ammonia. To make these emissions comparable we calculate from their amount and their acidification potentials the amount of SO2 which would yield the same contribution to acid rain. These "SO2 equivalents" are added and displayed.
  3. TOPP Equivalents (summer's smog): This is an aggregate of all emissions that have a potential to form precursors of tropospheric ozone, mainly organic compounds, nitrous oxides and carbon monoxide. Tropospheric ozone is the main reason for summer's smog formation. The potential of ozone formation is calculated from the amount and the respective ozone formation rates. The greater the amount of ozone precursor substances (Tropospheric Ozone Precursor Potential, TOPP), the greater the probability of summer's smog.
The internal calculation treats each gas separately, the aggregation is done in the very last step. Aggregation is necessary to keep the graphics clear while still showing the most important impact categories.

Graphics

Bar chart

The bar chart shows absolute emissions of CO2 equivalents, SO2 equivalents, and TOPP equivalents for each product system. The emissions that accrue in the "upstream processes" (i.e. during the production of the vehicle and the fuel) are displayed in shaded grey. For the vehicle we consider only the share of production emissions that corresponds to the share of journey distance to the expected lifetime of the vehicle.

The difference between upstream and total emissions yield the emissions during the utilization. For electricity powered vehicles, however, the emissions accruing during electricity generation are always considered to be upstream, so these have no direct emissions.

Bar chart
of PS1 and PS2

Star chart

The star chart has three axes to indicate the total emissions of each product system in the three emissions categories (i.e. no separation between upstream and direct emissions). For each emissions category, the maximum value from all product systems is set to 1 (=100%) and the values from the other product systems are shown relative to this maximum value. The values of each product system are assigned the same color.

This kind of graph makes relative differences between product systems explicit. For example, one sees very quickly if one product system has less emissions in all categories than another, and how large the relative differences are.

Star chart
of PS1 and PS2