Providing modern energy to the very poor—the population that the United Nations seeks to reach in its Millennium Development Goals program—would require an annual investment of about $41 billion per year over the next five years, or just 0.06 percent of global GDP, said the report.

Tackling the larger goal of universal energy access— reaching all 1.4 billion people who lack access to electricity and the 3 billion relying on unventilated and inefficient wood, charcoal, and dung cooking stoves—would require only a modest increase in carbon dioxide emissions, the report calculated. That’s because the amount of fuel needed to address basic needs is small, and the opportunities for using cleaner energy are great. If the world takes the problem on,