The EU Emissions Trading System (ETS) applies to sea freight shipments. This system, based on the 'cap and trade' principle, sets a cap on the total amount of certain greenhouse gases that can be emitted by Eu based companies. Within this limit, businesses can receive or buy emission allowances and trade them among each other. Since 2024, this has also been applied to the sea freight sector. The costs for this are generally passed on by shipping companies and freight forwarders; the calculation can vary, but usually involves a fixed amount per TEU (Twenty-foot Equivalent Unit).