Carbon Emission Accounting of Coal-fired Power Units Coupled with Unstable Power Sources

The rapid development of renewable energy represented by photovoltaic and wind power is an important feature of the current China's power industry transformation. Photovoltaic and wind power have significant randomness and volatility, so regulatory power supplies are essential to ensure the safety and stability of power supply. At present, coal power is the only large enough power source in scale that could meet the demand for flexible regulation of power systems. The role change as load-regulating power sources will change the design operating conditions and increase carbon emission density at the same time. So, this study developed a carbon emission accounting model on coal-fired power units with the life cycle carbon emission considered. The model realizes the carbon footprint accounting under the condition of coal power as a flexible power source. In addition, the model is applied for case studies under three operating conditions. The carbon emissions from the coal-fired power generation process account for about 98.11% of the lifecycle CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> emission. The carbon footprint density is 8.0% higher under deep peak conditions than designed condition, and 6.4% higher under start/stop conditions (within 24 hours). The carbon emission accounting model of coal-fired units helps carry out a comprehensive evaluation for coal power transformation.