Power of Haas Ideas

Dirty Tradeoffs

Greenhouse Gases versus Smog in China

By Prof. Catherine Wolfram

A soupy smog of particulates, ozone, sulfur, and nitrogen oxides hangs over Beijing, Tianjin, and other northern cities in China. The concentration of particulate matter in Beijing recently registered more than 15 times the highest recorded value in Los Angeles County.

Ex-pats are fleeing the country, while the lifespans of people who live in these cities fall. The primary culprits for much of the air pollution are the coal-fired power plants, which produce roughly 80 percent of China’s electricity.

Some of my cleantech colleagues seem to be almost cheering for Chinese smog, though. They seem to believe that the Chinese will be forced to invest in renewables and clean up their energy sector to address the local pollution. Because it is visible to the naked eye, has a distinctive smell, and has immediate impacts on quality of life, smog, unlike greenhouse gases, will spur a clean-energy transformation, some argue.

But I’m skeptical. I worry about the greenhouse gas implications of both demand- and supply-side responses to smog.

On the demand side, I worry people will react to air pollution by consuming more energy. In Singapore, 30 percent of households do not have air conditioning and simply open windows wide—this in a country with the third highest average income and beastly hot (to my Minnesota-born tastes) weather.

As air pollution increases, however, this natural, low-energy approach to air conditioning becomes less attractive. Moreover, wealthy Chinese are investing in air conditioners, air purifiers, and more people are spending time in air-conditioned underground shopping centers.

But if smog encourages governments to adopt renewables for energy production, it won’t matter that city-dwellers consume more energy, right? Maybe not. I have concerns about the supply-side responses to smog as well, because many technologies that are less polluting or remove pollution create more greenhouse gases.

Consider coal gasification, which transforms coal into methane. Power plants that burn natural gas emit many fewer pollutants than coal plants, so turning coal into natural gas and then burning the gas to make electricity can reduce local air pollution significantly.

China currently has one operating coal gasification plant and four under construction, and aims to produce the equivalent of more than 10 percent of its total gas demand using the technology by 2020. Unfortunately, coal gasification is a disaster for climate change.

Gasifying coal to burn in a natural gas power plant can produce almost twice as much greenhouse gas as a coal power plant. The only potential silver lining is that it appears much easier to sequester the CO2 emitted from coal that has been first been converted to gas than to sequester the CO2 from a coal power plant. But this will involve convincing the Chinese government to address both climate change, by investing in sequestration, and local smog, by gasifying their coal.

Of course, other options to reduce air pollution include building more nuclear plants, accessing Chinese shale gas reserves, burning gas instead of coal, and replacing old and inefficient coal plants with newer, more efficient plants fitted with pollution control technology. But, other than nuclear, these will go much further to reducing local air pollution than to reducing greenhouse gases.

So, we need to continue pushing for real climate solutions as we are unlikely to see a silver bullet emerge as the by-product of some other goal, like reducing air pollution.

This is a shorter version of a post on the Energy Institute’s blog.

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Smog in China