The Hydex is a cost-based price index. It reflects the average price for hydrogen ex electrolyser or ex steam reformer (with and without CO2 storage) in Germany. The Hydex is based on the short-term production costs of hydrogen. Capital cost are not included.

• The "Hydex Green" indicates the average price for hydrogen ex production site of an electrolyser. Green electricity certificates (guarantees of origin) are procured for the entire amount of electricity. It is assumed that in accordance with the EnWG and the EEG amendment, no network fees, EEG surcharges and electricity tax for the electricity used for electrolysis will apply.
• The "Hydex Blue" indicates the average price for hydrogen ex location of a natural gas steam reformer which includes the capture and storage of the released CO2 (so called CCS). For this process, emission certificates from the ETS only need to be procured for the remaining emissions.
• The "Hydex Grey" indicates the average price for hydrogen ex location of a natural gas steam reformer. For the released CO2, emission certificates must be procured within the framework of the EU Emission Trading System (ETS).
• The natural gas steam reformer is connected to the natural gas network. Average network tariffs for the gas connection of industrial customers are assumed.
• The Hydex refers to the lower heating value (LHV) of hydrogen.