The Oil Point Method (OPM) states environmental implications by quantifying requirements of fossil fuels.

One "Oil Point" (OP) is equal to the energy contents of one kilogram of crude oil. So, the less Oil Points a product or system scores, the better.

In using the Oil Point Method you perform three steps:

1. FOCUS on the problem,
2. EVALUATE by calculating Oil Points,
3. INTERPRET the result

To focus on the problem the goal, the life cycle processes and the functional unit should be determined. A goal could for example be: "Find the environmental problems caused by a vacuum cleaner."

Life cycle processes are those processes that take place within the life cycle stages, i.e. during 'material production', 'manufacturing', 'transport', 'use' and 'end-of-life'. An example is: "Injection moulding of 2 kg ABS plastic" in the manufacturing stage.

The functional unit describes exactly which service that is evaluated. Example: "Vacuum cleaning of 50 m2 regular carpet once a week over 10 years in a Danish home."

Oil point indicators should be found for all the life cycle processes determined in step 1. They can be found in tables or determined by one self. The oil point indicator for stainless steel is for example 1.6 OP/kg.

The oil points for the product can then be found by multiplying the oil Point indicators with the amounts occurring in the life cycle. This results in separated values for each life cycle stage and for the product as a whole. The oil points for 5 kg of stainless steel is 5 kg x 1.6 OP/kg = 8 OP.

Both the indicators can be found in the MS excel spreadsheet.

The interpretation includes evaluation of the influence of uncertanties, a view on the results in a holistic context and the seek for inprovement potentials.

There will always be some uncertain elements, e.g. the approximate weight of the product or the end-of-life scenario and chemical implications. For coping with these uncertainties, the values of each of these elements should be varied in extreme ranges in order to see how much influence this has on the overall result. If the influence is high, one may decide to look for better information. Chemical implications can be checked by means of a list of product groups that potentially incorporate undesirable substances.

The findings shoul be checked in an overall or holistic context. For example: Seen in a broad perspective, the material for a window frame may turn out to be less influential for the environmental performance of a window, if one is aware of the fact that the heat loss through the window pane represents a hundred times higher environmental impact than that of typical materials.

Inprovement potentials schould be sought at the places in the life cycle where the main impacts occur. This could be done by using a different material and/or different working principle.