Fatih Birol, the chief economist at the International Energy Agency, said $36 billion per year is needed in investments to provide energy services to the poor.
"There is a big gap between this figure and what is currently being invested," he said in a statement.
He noted that his agency's world energy outlook has "constantly and stubbornly" highlighted the prevalence of energy poverty.
The IEA estimates about 20 percent of the global population, some 1.4 billion people, don't have access to electricity. About 40 percent of those people live in sub-Saharan Africa.
The U.N. Advisory Group on Energy and Climate Change has called for a plan to advance global access to modern energy services by 2030. Critics, however, note that more electricity means more greenhouse gas emissions.
Birol claims the increase in greenhouse gas emissions from universal access to electricity would "actually be less than 1 percent."