Rapid Diffusion of Non-Fossil Energy in China Has Resulted in Less Efficient Coal-Fired Power Plants and Extra Fuel Cost

Non-fossil energy increases the non-dispatchability of power system, requiring fossil-based technologies to provide back-up capacity as dispatchable source. In a coal-based economy like China, it is coal-fired units that act as back-up capacity. We show that increase of non-fossil energy generation is associated with higher heat rates of coal-fired units, which can be explained by the decreased operating hours for dispatching. This side-effect is sizeable, accounting for 13% of carbon mitigation from non-fossil energy. The extra fuel cost is estimated to be 10.9 billion US dollars. We thus call attention to alternative technologies, such as large-scale storage, as dispatchable source