A Beijing environmental protection official vowed on Wednesday that the city will have an effective energy mix for the coming winter heating season.

During a visit to a former coal-fired boiler in Chaoyang district, Liu Wei, a deputy director of Beijing Environmental Protection Bureau, said the city will replace its use of coal with natural gas for downtown areas in an effort to reduce smog levels in the capital.

"The city is confident that it will reduce the concentration of dust, smoke and the amount of sulfur dioxide in the city as the project proceeds," Liu said.