Europe’s economic wellbeing and growth are highly energy dependent and heavily reliant on Russian imports of oil and gas. European energy security, its alternatives, and implications are examined in this chapter with the view of sustainability and the EU-Russian energy dialog. With an asymmetric mutual political-economic interdependency with Russia, Europe’s exposure in oil and gas calls for sustainable energy solutions. Meantime, Russia, the key energy supplier in the European region, is also a major energy consumer whose economy is characterized by high energy intensity. Russian energy sector needs serious improvements in technology, investment, and management: failure to address these priorities erodes Russia’s reliability as major regional energy supplier. The chapter explores the dynamics of Russian energy sector and implications for European energy security and sustainability.