Use clean energy for heating to reduce smog

Another thick shroud of smog has covered cities in North, Central and even East China, forcing the closure of expressways and delaying flights, and compelling Beijing to issue an orange alert, the second-highest level in a four-tier emergency response system, for the week-long heavy air pollution.

Bad weather is surely responsible for the situation, but smog is more common in winter because huge quantities of coal are burned to supply heating in most northern cities. Worse, many residents in rural and suburban areas, where central heating system is not available, still use primitive boilers that emit considerable coal-related pollutants to keep warm in winter.

The need for clean, renewable energy as an alternative to coal is therefore more urgent than ever. Given the technological difficulties in using wind and solar power for heating supply, a more feasible solution lies in the use of electricity, which can be generated by green energy as well as coal. In fact, about 30 percent of electricity in China is provided by clean energy.

But electricity - and gas-fueled heating costs more than coal-powered heating, which explains why some rural residents do not embrace the former if it is not sponsored by local authorities. Yet the use of coal has to be reduced, and the options are not many: Gas-fueled heating facilities are welcome, but China's limited gas resources could pose a challenge to energy security were the country to import gas in large volumes.

However, there is plenty of room for reform in China's coal consumption, nearly half of which is used for generating electricity. The efforts to transform electric energy into heat energy are about making the most of the other half of the total coal consumption.

Ideally, such a transformation should play a key role in reallocating excess electricity, promoting the use of green energy and reducing air pollution. China has fairly harsh emission restrictions on thermal power plants, about 70 percent of which started operations after 2003. Compared with old power plants with a service life of 40 to 50 years in other countries, China's thermal power has a relatively advanced system of higher technology.

In other words, most Chinese thermal plants are quite new and can efficiently keep their pollutant emission levels under control. If run at peak efficiency, they have the potential to replace other coal-consuming sectors with much less pollution. On average, the thermal power plants are seven to eight times more efficient than medium- and small-sized boilers in curbing pollutant emissions. That explains why most developed economies use at least 80 percent of their coal consumption to generate electricity.

Introducing electricity-powered heating system will also help tackle the oversupply of renewable energy like wind and photovoltaic power in West China. But despite the official endorsement and subsidies, the actual market demand for photovoltaic power remains unpromising even in the sunshine-rich northwestern areas.

Statistics show that the usage of photovoltaic power in Shaanxi, Gansu and Qinghai provinces, and the Ningxia Hui and Xinjiang Uygur autonomous regions, was just 611 hours in the first half of 2016. Cities in East China, too, have a small appetite for it. So instead of allowing the overcapacity to be wasted in vain, it can be put to better use in thermal power plants.

For thermal power producers, relatively stable electricity tariffs are a bonus, because they allow the producers to lower the cost without worrying about fluctuations in fuel prices. And since electricity-powered heaters will also save rural residents the trouble of burning coal during winter, governments at all levels should work out long-term policies and provide needed subsidies to supply electricity-powered heating at lower costs.

The author is dean of China Institute for Studies in Energy Policy at Xiamen University.