The recent economic sanctions against Russia can jeopardize the sustainability of the European Union’s (EU) energy supply. Despite the EU’s strong commitment to stringent abatement targets, fossil fuels still play a significant role in the EU energy policy. Furthermore, high dependency on Russian energy supplies underlines the vulnerability of the EU energy security. Using a global computable general equilibrium model, we prove that the current EU embargo on coal and oil imported from Russia will have adverse supply effects, substantially increasing energy prices and welfare costs for the EU resident. Although it reduces emissions, extending the embargo to include natural gas doubles this welfare cost. The use of coal is likely to increase, especially with respect to EU electricity generation, given the current constraints of additional import capacities from nonRussian producers. The impact on Russia once the EU extends the sanctions to natural gas is less substantial than on the EU. Russian welfare cost will increase less than 50%, indicating that extending the current restriction to boycott Russian gas is a costly policy option.