By way of derogation from Article 16(2)(a) and Article 18(1)(a), the preliminary annual number of emission allowances allocated free of charge for a product benchmark sub-installation relating to the production of high value chemicals (‘HVC’) shall correspond to the value of the steam cracking product benchmark for the relevant allocation period multiplied by the historical activity level determined in accordance with Annex III and multiplied by the quotient of the total direct emissions including emissions from net imported heat over the baseline period referred to in Article 15(2) or of the first calendar year after the start of normal operation referred to in F1Article 17(1)(a), as appropriate, calculated in accordance with Article 22(2) and expressed as tonnes of carbon dioxide equivalent and the sum of these total direct emissions and the relevant indirect emissions over the baseline period referred to in Article 15(2) or of the first calendar year after the start of normal operation referred to in F1Article 17(1)(a), as appropriate, calculated in accordance with Article 22(3). To the result of that calculation, 1,78 tonnes of carbon dioxide per ton of hydrogen times the mean historical production of hydrogen from supplemental feed expressed in tons of hydrogen, 0,24 tonnes of carbon dioxide per ton of ethylene times the mean historical production of ethylene from supplemental feed expressed in tons of ethylene, and 0,16 tonnes of carbon dioxide per ton of HVC times the mean historical production of other high value chemicals than hydrogen and ethylene from supplemental feed expressed in tons of HVC, shall be added.