The Wall Street Journal
September 28, 2009
SHANGHAI—China’s ambition to create “green cities” powered by huge wind farms comes with a dirty little secret: Dozens of new coal-fired power plants need to be installed as well.
Part of the reason is that wind power depends on, well, the wind. To safeguard against blackouts when conditions are too calm, officials have turned to coal-fired power as a backup.
China wants renewable energy like wind to meet 15% of its energy needs by 2020, double its share in 2005, as it seeks to rein in emissions that have made its cities among the smoggiest on Earth. But experts say the country’s transmission network currently can’t absorb the rate of growth in renewable-energy output. Last year, as much as 30% of wind-power capacity wasn’t connected to the grid. As a result, more coal is being burned in existing plants, and new thermal capacity is being built to cover this shortfall in renewable energy.
In addition, officials want enough new coal-fired capacity in reserve so that they can meet demand whenever the wind doesn’t blow. This is important because wind is less reliable as an energy source than coal, which fuels two-thirds of China’s electricity output. Wind energy ultimately depends on wind strength and direction, unlike coal, which can be stockpiled at generators in advance.
Further complicating matters is poor connectivity between regional transmission networks, which makes it hard for China to move surplus power in one part of the country to cover shortfalls elsewhere.
China may not be alone in having to ramp up thermal power capacity as it develops wind farms. Any country with a combination of rapidly growing energy demand, an old and inflexible grid, an existing reliance on coal for power, and ambitious renewable energy-expansion plans will likely have a similar dilemma. What marks China out as different is the amount of new coal-fired capacity that needs to be added.
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