The United Kingdom Emissions Trading Scheme (the “UK ETS”) was established by the Greenhouse Gas Emissions Trading Scheme Order 2020 (the “UK ETS Order”). The UK ETS runs for ten years, split into two five-year “allocation periods”. Operators of certain industrial installations are required to monitor, submit verified reports on, and surrender “allowances” equivalent to, their greenhouse gas emissions each year. Allowances are sold at auction, but some operators of installations and aircraft operators receive an allocation of allowances free of charge. For installations that meet the eligibility criteria, there are two schemes in addition to the main scheme, one for “hospitals or small emitters”, the other for “ultra-small emitters”.