The different energy sources, their costs and impacts on the environment determine the electricity production process. Energy planning must solve the existence of uncertainty through the diversification of power generation technologies portfolio. The European Union energy and environmental policy has been mainly based on promoting the security of supply, efficiency, energy savings and the promotion of Renewable Energy Sources. The recent European Commission communication “Towards an European Energy Union: A secure, sustainable, competitive and affordable energy for every European” establishes the path for the European future. This study deals with the analysis of the latest EU “Energy Union” goals through the application of Markowitz portfolio theory considering technological real assets. The EU targets are assessed under a double perspective: economic and environmental. The model concludes that implementing a high share of Renewable Energy target in the design of European Policies is not relevant: the maximization of Renewable Energy share could be achieved considering a sole Low Emissions of carbon dioxide policy. Additionally it is confirmed the need of Nuclear energy in 2030: a zero nuclear energy share in 2030 European Mix is not possible, unless the technological limits participation for Renewable Energy Sources were increased.