The Bureau of Energy, from the Ministry of Economic Affairs, published the revised results of the power emission factor for the year 2017. In Taiwan, each kWh's carbon dioxide emission was 0.554 Kg carbon dioxide equivalent (CO2e), up 0.024 Kg (CO2e) from the year of 2016.
There were two reasons why Bureau of Energy (BOE) revised the data. First, according to the periodic regulatory goals of greenhouse gas (GHG) emission scope in the target sectors, BOE reviewed and corrected the fuel input's cost share methodology of combined heat and power (CHP) during the year 2017. Next, because energy companies changed their application details, BOE has retroactively modified their power emission factors from the year 2017 back to 2005, and revealed these documents for the public's references.
So as to ensure the correctness of power emission factor, each year BOE will do three things. First, it would follow the power emission factor calculation's standard operating procedure. Next, it would invite outside experts, so that they will view the quoted data and examine the consistency and reliability of the results. The third thing that BOE would do is regularly review the power emission factor's calculation methodology.
BOE particularly pointed out the following four causes, to explain why the power emission factor in the year of 2017 increased by 0.024 Kg CO2e from the year 2016. First, the portion of electricity generated by PV power, wind power, and low-carbon natural gas power have continued increasing as the government carried out its energy transition policy.
In particular, PV power generation and wind power generation in 2017 was 0.33 percentage points higher than 2016 in terms of total sales volume of electricity. Natural gas power generation's portion in total sales volume of electricity in 2017 was 2.61 percentage points higher than that of 2016.
Second, the economic outlook and climate change increased sales volume of electricity systems by 2.38%, and dropped water power generation's sales volume by 9.44%. Thus, water power generation's portion dropped by 0.56 percentage points.
Third, nuclear power generation portion dropped 4.16 percentage points because various events have caused Taiwan’s nuclear power units to pause.
Fourth, in order to fulfill domestic power demand, the sales volume portion of electricity for coal and oil rose by 1.46 percentage points and by 0.37 percentage points from the year 2016, respectively. Affected by the factors above, the power emission factor in the year of 2017 increased by 0.024 Kg CO2e from the year 2016.
In order to cooperate with periodic regulatory goals of GHG emission scope in the target sectors, BOE explained why it adjusted the formula of CHP and resulted in different sets of power emission factors in the chart below. The data are compared before the adjustment and after the adjustment. The more detailed actions are explained below.
In 2017, BOE has retroactively modified power emission factor from the year 2017 back to 2005 for the following reasons. First, BOE referred to International Energy Agency (IEA)'s advice, considered the purpose for CHP process' waste heat power generation, and consulted with CHP system experts and manufacturers. Second, BOE estimated how much fuel are necessary to generate heat energy (from the steam), and calculated the rest of fuel input as producing electricity. In this way, BOE reviewed and corrected the fuel input's cost share methodology of CHP during the year 2017.
According to BOE, the year 2017's announcement of power emission factor will be the reference data of indirect emission for GHG inventory of purchased electricity.
BOE will continue to improve the quality control for power emission factor calculation procedure and data, so as to ensure the correctness of power emission factor and to enhance the reliability of sectors' GHG inventory reference data.