I have read a number of news stories about air pollution in the major Chinese cities recently. A soupy smog of particulates, ozone, sulfur and nitrogen oxides hangs over Beijing, Tianjin and other northern cities. The concentration of particulate matter (PM2.5) in Beijing recently registered at 501 μg/m3, 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 clean tech 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 cleanup 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. Or, so some argue.
I love the idea of killing two birds with one stone as much as the next person, but I’m skeptical of this particular application. I worry about the greenhouse gas implications of both demand- and supply-side responses to smog.
On the demand side, I worry that people will react to air pollution by consuming more energy. I was in Singapore recently and stunned to learn that 30% of the households do not have air conditioning — this in a country with the third highest average income and beastly hot (to my Minnesota-born tastes) weather. If I had to live in Singapore without air conditioning, I might never sleep.
But, a good share of the local Singaporeans seem to think that “air conditioning” involves opening the windows wide and capturing any wisp of a breeze.
As air pollution increases, the natural, low-energy approach to air conditioning becomes less attractive. My colleague at the National University of Singapore, Alberto Salvo, is working on a study that will document by just how much air conditioner purchases and electricity consumption increased in a recent episode of poor air quality.
Similarly, wealthy Chinese are investing in air conditioners, air purifiers, and more people are spending time in the miles and miles of air conditioned underground shopping centers that seamlessly connect with above ground buildings. If the air is hot, muggy and polluted, why ever go outdoors?
But, if smog encourages governments to adopt renewables for energy production, it won’t matter that city-dwellers are consuming more energy. Will that work? I have concerns about the supply side responses to smog as well.
Unfortunately, most commercial-scale technologies that remove local pollution from the energy sector create more greenhouse gases. In other words, greenhouse gases and local pollutants are typically substitutes and not complements in the production process.
Consider coal gasification, a process that transforms coal into methane. Power plants that burn natural gas emit many fewer criteria 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. The government recently announced plans to produce the equivalent of more than 10% of its total gas demand using the technology by 2020. In fact, if the gas that was created from the five plants under construction plus four others that are already permitted were all used to generate electricity in an efficient combined cycle natural gas plant, it would produce more electricity than China’s wind turbines.
So, coal gasification will help reduce local pollution and it appears commercially viable, at least in China. Unfortunately, it’s a disaster for climate change.
This study, reports that, “If all 40 or so of the projected [coal to gas] facilities are built, the GHG emissions would be an astonishing ~110 billion tonnes of CO2 over 40 years.” To put this in context, all of China currently emits less than 10 billion tons annually. Gasifying coal to burn in a natural gas power plant can produce almost twice as much greenhouse gas as a coal power plant.
As far as I’m concerned, 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 that they need to address both climate change, by investing in sequestration, and local smog, by gasifying their coal. Unfortunately, there’s no free lunch from addressing smog.
Of course, coal gasification is not the only, nor necessarily even the cheapest, means of reducing local air pollution. Other options include building more nuclear plants, accessing Chinese shale gas reserves and burning gas instead of coal, replacing old and inefficient coal plants with newer more efficient plants that are also fitted with pollution control technology (scrubbers/bag houses, etc.). 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.
The Berkeley Blog