In Poland, the cost of the EU ETS accounts for half of industrial energy prices.

Omissions

• The 50% figure is presented in the sources as a maximum ('może sięgać nawet 50 proc.' / 'up to 50%'), not as a typical or average value — the MEP turned an upper bound into a general statement.
• The figure refers specifically to electricity sold to industry; it is not a share of industrial energy prices across all carriers (gas, heat, fuels), where the ETS-related share is different.
• No primary official statistic (Eurostat, European Commission, KOBiZE, Polish statistics office) publishes a 'share of ETS cost in industrial energy prices' indicator; the claim rests on secondary/industry estimates whose publication dates could not be established in this check.
• The share depends heavily on the EUA price and wholesale power prices in a given period, so it fluctuates substantially over time.

Sources

• SecondaryGazeta Prawna (Dziennik Gazeta Prawna)"Koszty ETS coraz mocniej obciążają ceny energii w Polsce. W przypadku prądu sprzedawanego przemysłowi ich udział może sięgać nawet 50 proc." (ETS costs increasingly weigh on energy prices in Poland; for electricity sold to industry their share may reach as much as 50%).
• SecondaryCIRE.pl (Polish energy information portal)"Aż 59 proc. średniej ceny energii to ceny uprawnień do emisji CO2 wynikające z polityki klimatycznej UE" (as much as 59% of the average energy price is the price of CO2 emission allowances resulting from EU climate policy).
• TertiaryEnerace (energy analysis blog)"In Europe, the ETS system generates significant costs – in Poland, up to 50% of the energy price is due to CO₂ emission allowances."