Factbox: Windfall tax mechanisms on energy companies across Europe
Several governments across Europe have imposed windfall taxes on energy companies this year to reign in excess profits as energy prices have soared following Russia's invasion of Ukraine.
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### Instruction: Factbox: Windfall tax mechanisms on energy companies across Europe

### Response: Several governments across Europe have imposed windfall taxes on energy companies this year to reign in excess profits as energy prices have soared following Russia's invasion of Ukraine.