Ideally, the environmentally relevant equipment shall be flagged by the types of environmentally relevant investment categories in SAP or other accounting systems at the point of time when a project code is being defined. Once the SAP flag for the environmental investments is realized, the actual depreciation can be traced by a SAP run and also the total annual amount of environment related investments is available without any further investigation. If this is not possible (or for existing equipment), it may also be a solution to estimate the average life time and not record the actual depreciation from asset management.