| 31.12.2014 | 31.12.2013 | |
|---|---|---|
| Guarantees of origin | 12,993 | 16,397 |
| Emissions certificates | 2,896 | 2,593 |
| Gas | 6,733 | 12,061 |
| Material inventories | 9,598 | 9,278 |
| Total | 32,220 | 40,329 |
Inventories consist of material inventories, gas inventories and certificates, and are measured at the lower of acquisition costs and net realisable value. Certificates that are not necessary for own generation needs and which are held for trading purposes are measured at fair value less selling costs. In the 2014 financial year an impairment loss of TCHF 774 was recognised (no impairment loss the previous year).