The book examines the legal guarantees provided under the European Union (EU) and the World Trade Organization (WTO) rules for the development of electricity transmission systems, either by constructing new transmission lines or by increasing transmission capacity. In the context of an analysis of trade rules, the book makes the argument that, if long-distance trade in electricity remains a feasible option, the development of electricity transmission projects must be made subject to economic, technological, and environmental criteria. This topic is dealt with in light of specific challenges of electricity trade related to its dependence on networks, storage and balancing. The book offers insights into the scope of the WTO and the EU related to access to and the development of cross-border electricity infrastructure development, connection, and integration of abundant renewable energies into the electricity systems. It criticizes the EU's regulations in terms of a lack of technological neutrality, as well as the WTO system in terms of lack of sector-tailored regulations that are necessary to achieve the objectives of the WTO to facilitate trade and transit. The regulatory environment for the development of cross-border electricity transmission projects has been examined based on identified obstacles from the analysis of the major multinational electricity systems in the world.