11 Inventories

11 Inventories
  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).