Abstract. In December 2015 (Paris Agreement) 174 countries and the European Union agreed to reduce their greenhouse gas emissions (GHG) to limit the global average temperature increase to well below 2°C above pre-industrial levels. As electricity generation produces about 40% of the world’s CO2 emissions, this energy sector is at the centre of technological efforts to reduce carbon emissions. This transition has been called decarbonisation (or decarbonization) of the electric power sector. An ambitious sustainable scenario for the 21st century involving many uncertainties. Meeting these climate goals means reducing the carbon intensity of the electricity power sector by as much as a factor of ten. The UN Climate Action Summit (New York, 2019), succeeded in focusing the attention of world leaders, the private sector and civil society, on the urgency for action to address the climate emergency. This review contains a number of recent studies that revealed the extreme climate change outcomes requiring near‐total decarbonization of the world’s energy system with 50–90% reductions in energy‐related CO2 emissions required by 2050.Studiestake into account the projected economic and population growth in the next 30 years meaning that the global energy system must deliver roughly twice as much energy as today. The US and China are the first two countries with the biggest electricity power sectors on a global scale with more than 60% of electricity produced by fossil fuels. But there are promissing recent trends.The rapid cost reductions in renewable energy sources (wind, solar, tidal and others) and advances in storing energy and digital technologies for distribution are opening huge opportunities for cheaper renewable energy transitions. Although the share of renewables in global electricity generation reached 26% in 2018, renewable power still needs to expand significantly to meet the Sustainable Development Scenario of at least 50% of global energy generation with renewables by 2030. In conclusion, the energy sector (responsible for 2/3 of global GreenHouse Gases) must be at the core of efforts to prevent emissions from the electricity power sector.