The article reviews the main provisions of the World and Russian Energy Sector Development Projections for the period until 2040. The projections are built with the SCANER modelling and information complex, which uses optimization, econometric analysis and a balance approach. The article reveals three scenarios of international energy markets development and presents key possible changes. Each of the scenarios envisages factors that have a potential to affect Russia’s economy in general and the energy sector in particular, and the characteristics of such influence are provided in the third section of the article. Within the Baseline scenario, the contribution of the energy sector to Russian GDP will decrease by half over the period until 2040. Therefore, although the energy sector will continue to be the basis of the Russian economy, it will cease to be the engine for its growth. Russian economic policy will have to face the necessity of reducing the country’s excessive dependence on oil and gas revenues. The «New Producers» scenario gives a more pessimistic outlook: Russian supplies to the world oil and gas markets are being pushed out by cheaper production in other countries. The «Other Asia» scenario, on the contrary, provides a window of opportunity for Russia to strengthen its presence in the rapidly growing Asian market. In any of the scenarios, the Russian energy sector will continue to make significant contribution to the economy in absolute terms, but other sectors will have to deliver the economic growth.