Nov. 19 (Bloomberg) -- Wind turbines, solar panels and hydropower stations won’t be built fast enough to keep pace with global electricity demand through 2030, the International Energy Agency forecast.

The CHART OF THE DAY shows a widening gap between power generated with renewable fuels and total consumption. That means coal-fired plants, which are cheaper and more polluting, will increase their share in the energy mix, discharging extra heat- trapping emissions that threaten to raise the planet’s temperature, the IEA said.

To supply ballooning consumption in developing nations such as China and India, new generators will be needed that can produce more than four times the total electricity potential now in the U.S., the IEA said. That will cost $13.7 trillion, the Paris-based adviser to oil-consuming nations said, basing its scenario on existing state policies for fossil-fuel use.

“We should expect coal to still be the primary generation choice in the future,” said Jose Garcia, senior associate at the consultant Brattle Group in Madrid. “It’s logical to assume that the least-expensive technology alternatives should become the likely choices for new generation capacity.”

Burning coal will contribute 44 percent of power by 2030 compared with about 41 percent now, the IEA said. A ton of coal may cost $109 in 2030, less than $120 in 2008, the adviser said.

“We’re going to need both renewable energy and energy efficiency” to stop the gap from widening further between demand for electricity and supply of low-carbon energy, said Claudia Kemfert, chief energy analyst at the Berlin-based DIW economic institute.

To contact the reporter on this story: Jeremy van Loon in Berlin at jvanloon@bloomberg.net.