The rate of expansion of access to electricity will have to double over the next 17 years if the world’s population is to achieve 100 percent access to modern energy, a new report says. While about 1.7 billion people became connected to electricity sources worldwide between 1990 and 2010, that increase barely outpaced population growth during that period, according to Sustainable Energy for All, a group lead by the World Bank and the United Nations. More than 1.2 billion people still do not have access to electricity, and 2.8 billion still rely on burning wood or other biomass for household fuel, a source of pollution that causes about 4 million premature deaths annually. Achieving universal access to modern energy will require investments of $45 billion annually, which is five times the current levels. If combined with an expansion of renewable energy sources and improved efficiencies, however, achieving this growth in energy access would increase CO2 emissions by less than 1 percent, the report says.