Currently, resources constraints, climate change, environmental pollution and population without access to electricity pose severe challenges to the global sustainable development. To approach these challenges, it is pivotal to comply with the growing trend of the clean, electrified, interconnected and intelligent energy system, quicken the establishment of the cleanness-oriented, electricity-centered, interconnected, co-built and shared modern energy system. Global Energy Interconnection (GEI) refers to the development of a globally interconnected, ubiquitous robust smart grid, supported by backbone UHV grid (channels), and it is a vital platform for worldwide large-scale deployment, transportation and utilization of clean energy. Establishing GEI, and accelerating "two replacements, one increase and one restore" provide an efficient solution for all countries to realize energy system transition.

Based on the concept of "Green, Win-Win, Collaborative, and Sustainable" and the theory of GEI, the Global Energy Interconnection Development Index (GEIDI) is proposed to reflect the development level of national and regional power system, energy system, and economy, society and environment coordination. GEIDI as a comprehensive index provides an integrated system to demonstrate and analyze the development level and implementation effectiveness of world’s energy system transition. The GEIDI is composed of three subindexes, namely the Power Interconnection Index，the Green & Low-Carbon Index, and the Energy, Economy, Society and Environment Coordination Index, which embody the core essential and strategic value of the GEI in promoting the world's energy system transition.

Based on the theory of GEI, the GEIDI is composed of three subindexes evaluated by 18 quantitative indicators.

The regional and national GEIDI ranking and the three subindex rankings are then evaluated and analyzed according to the collected data and analysis regarding to energy, electricity, economy, society, and environment in 140 countries and 10 regions around the world.

The Belt and Road Initiative and Global Energy Interconnection

▲The Belt and Road Initiative schematic

The Belt and Road Initiative (hereinafter referred to as the initiative) is an important initiative oriented to the 21st century to adapt to economic globalization. It includes the Silk Road Economic Belt, the 21st Century Maritime Silk Road, the Pacific Maritime Silk Road and the Polar Silk Road. The initiative has reached consensus worldwide and become a global option to foster sustainable development of all countries. As of 2016 the initiative had won the support and participation of more than 100 countries and international organizations. More than 80 of these countries and international organizations have signed related cooperation agreements. China has cumulatively invested more than USD 500 billion in the countries along the Belt and Road Initiative area.