11 Inventories

11 Inventories
  31.12.2013 31.12.2012
Guarantees of origin 16,397 16,350
Emissions certificates 2,593 2,141
Emissions certificates held-for-trading - 2,614
Gas 12,061 14,539
Material inventories 9,278 9,246
Total 40,329 44,890

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. No impairment loss was recognised in the current financial year or in the previous year.