Background

With the development of technology in electricity generation and the changes to the ratio of different types of electricity supply, the consumption of fossil fuels as well as the emission of greenhouse gases per kWh electricity supply go down evidently, Applying the outdated electricity data developed several years ago for LCA may lead to higher emission and impact than reality. To calculate the environmental impact more accurately, we updated the consumption of fossil fuels and GHG emissions per kWh electricity supply for the national grid and provincial grid.

If you have any question or comments please email Dr. Wang（jason@1mi1.cn）or Bill （support@1mi1.cn)  

 

Update steps:

1.      Obtain the provincial thermal power generation and fossil fuels consumption from the Statistical Yearbook of China’s Energy 2016;

2.     Obtain the net calorific values and the default carbon dioxide emission factors of different types of fossil fuels from Statistical Yearbook of China’s Energy 2016 and National Guidelines for Provincial Greenhouse Gas Inventories (Pilot Edition);

3.      Obtain the default methane and nitrous oxide emission factors from the 2006 IPCC Guidelines for National Greenhouse Gas Inventories;

4.     Convert energy types into standard coal equivalent and calculate the carbon dioxide, methane, nitrous oxide emission of different types of fossil fuels based on the methods proposed in 2006 IPCC Guidelines for National Greenhouse Gas Inventories;

5.     Thermal power plants consist of coal-fired power plants, oil-fired power plants, gas-fired power plants. There are several kinds of fossil fuels used as inputs in the three kinds of thermal power plants showed in Table 1.

Table 1. Fossil fuels used in thermal power plants

Type of Thermal Power Plants	Type of Fossil Fuels
Coal-fired power plant	Raw coal, Refined coal, Other coal, Briquette, Coke, Other Coking Products, Gangue, Petroleum Coke
Oil-fired power plant	Crude oil, Gasoline, Diesel, Fuel oil, Other Petroleum Products
Gas-fired power plant	Natural gas, LNG, Coke Oven Gas, Other Gas, Blast Furnace Gas, Converter Gas, Refinery Gas

6.      Assume that the electricity generation of these three kinds of thermal power plants is proportional to the calorific values of the fossil fuels they each consumed. Then we allocate the provincial electricity generation by the thermal power plant to coal-fired, oil-fired and gas-fired power plant. Table 2 shows the electricity generation of each kind of thermal power plants in different provinces of China.

 

Table 2. Electricity generation by thermal power plant types and provinces

Province	Total Electricity Generation	Electricity Generation by Coal-fired Power Plants	Electricity Generation by Oil-fired Power Plants	Electricity Generation by Gas-fired Power Plants
	108 kWh	108 kWh	108 kWh	108 kWh
Beijing	412.53	50.77	0.99	339.32
Tianjin	635.88	511.13	6.40	73.83
Hebei	2288.70	1794.78	1.25	284.96
Shanxi	2318.60	2168.25	0.00	99.78
Inner Mongolia	3421.93	3386.24	2.65	26.43
Liaoning	1329.13	1242.24	2.47	77.36
Jilin	589.83	558.62	0.12	6.32
Heilongjiang	803.62	764.66	0.80	12.31
Shanghai	810.34	677.27	2.03	116.09
Jiangsu	4160.63	3675.06	0.61	383.86
Zhejiang	2261.42	2001.22	0.30	154.25
Anhui	1988.92	1884.77	0.16	59.84
Fujian	1108.96	1017.79	1.40	85.27
Jiangxi	780.47	730.25	0.09	46.37
Shandong	4552.85	4225.36	1.03	148.37
Henan	2564.81	2303.50	0.82	87.63
Hubei	993.86	881.19	0.44	68.31
Hunan	710.75	635.50	1.41	37.53
Guangdong	2933.66	2410.00	8.29	334.43
Guangxi	544.25	453.13	0.45	53.73
Hainan	234.58	206.04	0.01	23.37
Chongqing	447.45	412.03	0.28	27.21
Sichuan	450.32	339.31	0.19	67.31
Guizhou	1071.15	1036.28	0.90	24.01
Yunnan	277.85	242.62	0.16	20.55
Shaanxi	1452.38	1131.97	0.10	82.93
Gansu	720.41	697.33	0.12	6.68
Qinghai	122.00	117.69	0.03	2.28
Ningxia	1029.21	1018.81	0.13	5.24
Xinjiang	2059.96	2035.64	0.42	26.13

7.      auxiliary power ratio in different provinces from 2015 Statistics of the Electric Power Industry. Assuming that different kind of thermal power plants share the same auxiliary power ratio within each province. Then we calculate the electricity supply from coal-fired, oil-fired and gas-fired power plants. The process is expressed as: 

 

 

where E supply, and Egene denote the electricity supply and electricity generation respectively by different provinces and techniques, Yauxi denotes the auxiliary power consumption ratio of thermal power plants in different provinces.

8.   Calculate the amount of hard coal/oil/gas consumption per kWh electricity supply by coal-fired/oil-fired/gas-fired power plants in different provinces.

9.     Calculate the carbon dioxide, methane, nitrous oxide emissions per kWh electricity supply by coal-fired/oil-fired/gas-fired power plants in different provinces.

10.   Derive the net electricity exchanged among China Six Grids (Northeast China, Northwest China, North China, Central China, East China, South China) based on 2015 Statistics of the Electric Power Industry. Figure 1 shows the electricity flows among grids.

Fig1. Electricity Flows among China Six Grids (10⁸ kWh)

11.   Assume that each Grid first mix the electricity generated from the provinces, the mixed electricity also covers the net electricity it receives from other Grids, then the mixed electricity is exported to other Grids which are net electricity receiver. Based on the above statistical assumption, we derive how much percentage each provincial generated electricity account for in each Grid.

12.   The update of China’s electricity data in Ecoinvent database (China regionalized) is demonstrated in Figure 2.

i.      Update China’s high voltage electricity data. First, update the amount of hard coal/oil/gas consumption and carbon dioxide, methane, nitrous oxide emissions per unit of electricity supply by coal-fired/oil-fired/gas-fired power plants in different provinces. Second, update the share of electricity supply that different electricity generation techniques, such as hydropower, wind power and nuclear, account for at the province level. Third, update the share of electricity supply that different provinces account for at the Six-Grid level.

ii.      Update the Six Grid’s medium voltage electricity data. Because high voltage electricity is one of the inputs for medium voltage electricity generation, we substitute the past high voltage electricity data with the new ones.

iii.    Update the Six Grid’s low voltage electricity data. Because medium voltage electricity is one of the inputs for low voltage electricity generation, we substitute the past medium voltage electricity data with the new ones.

13.   Application：to update all the electricity data in SimaPro, to replace any other country’s high/medium/low voltage electricity data with China’s high/medium/low voltage electricity data.

Reason: Considering the lack of China’s local LCI database, researchers usually use process data from the EU or The US as substitutes to do life-cycle assessment on China’s products. Most of these process data consume electricity. And in some of them, the electricity consumption accounts for more than 80% of the environmental impacts of the process. To substitute other country’s electricity data with China’s electricity data is a good way to obtain a better approximation of China’s process data.

Fig 2. The steps of updating Six Grid’s electricity data

 

Results:

We apply the IMPACT 2002+ method to evaluate the environmental impacts of one kWh of high voltage electricity supply in Six Grids. Figure 3 shows five aspects of environmental impacts including aquatic ecotoxicity, global warming, and non-renewable energy.

In all the three types of environmental impact, Northeast China Grid is the highest among Six Grids. And 1.32 kgCO₂eq is emitted for 1kWh electricity supply in this Grid.

Central China Grid and South China Grid have the least environmental impacts, only emit about half of CO₂ equivalent per kwh than Northeast China Grid.

 

Fig 3. The environmental impacts of 1kWh electricity supply in Six Grids.

 

Notes:

1. In this update. We use the assumption that the power plant's internal electricity consumption ratio is identical for coal, gas and oil-fueled electricity in each province by adopting the ratio of coal-fired power plants in the provinces as default. In reality, the ratio is different for the three types of electricity. When detailed data is available, a more accurate estimation can be done. In addition, the internal consumption ratio for Ningxia Province is missing, we use China national average ratio to substitute the missing index;

2. Besides fossil fuel-based electricity, the amount of renewable energy-based electricity, e.g. solar, wind, hydro and nuclear-based electricity is sourced from the book of 2015 Statistics of Electric Power Industry.

3. The internal electricity consumption ratio for hydropower electricity is missing for Tianjin, Shanghai, and Ningxia, we use China's national average figure for these three regions. For the other types of renewable energy-based electricity, we use the ratio from a representative case study. The ratio for wind power is 4.22%, photovoltaic power 4.00%, solar thermal electric power 10.00%, and nuclear power 6.71%.