Study of urban carbon dioxide equivalent (CO₂e) accounting based on the comparable GPC framework: a case of the underdeveloped city, Nanning, China

Figures & data

Table 1. Comparison of current major methodologies for urban CE accounting.

Method	Author (Year)	Category	Summary or assessment
The Greenhouse Gas Protocol	WRI/WBCSD (2004)	bottom-up	Divided emission into three scopes Several sectors: energy, metals, chemicals, minerals, waste, pulp and paper, et al. mainly used in corporate CE accounting
IPCC	IPCC (2006)	bottom-up	A guidance on emission factor, data and equation, et al. Four sectors: Energy, IPPU, Waste and AFOLU mainly used in national CE accounting
Dhakal	Dhakal (2009)	top-down	Adopted energy use per unit GRP as a key indicator to estimate divided city CEs Emission factors were from IPCC 2006
Kennedy	Kennedy et al. (2010)	bottom-up	Adopted three scopes proposed by WRI/WBCSD Six sectors: electricity, transportation, IPPU & waste, et al.
Bi	Bi et al. (2011)	bottom-up	Also six sectors but different slightly from Kennedy The earliest case of a developed city in China
Lin	Lin et al. (2013)	hybrid	Calculated the emissions from three scopes Scopes 1 and 2 were estimated using the IPCC 2006; and Scope 3 was calculated using the life cycle analysis (LCA)
GPC	C40 et al. (2014)	bottom-up	Contained three scopes and five sectors Based on IPCC 2006; but more comprehensive, transparent and accurate, and specifically suitable for cities
PAS 2070	BSI (2014)	hybrid	Direct plus supply chain method was equal to GPC Consumption-based method used the IO models from a life cycle perspective
Zhang	Zhang et al. (2015)	top-down	Adopted 135-sector IO tables The others were the same as Dhakal

Figure 1. Accounting sectors (included in dotted rectangle) of Nanning’s CE based on the GPC framework.

Figure 2. Accumulative results of energy consumption CE from all industrial subsectors.

Figure 3. CO₂e emissions from household (a) and commercial (b) energy consumption.

Figure 4. Accumulated CEs of different traffic tool types.

Figure 5. CO₂e emissions from private cars, taxis and buses (a) and their respective shares (b).

Figure 6. CO₂e emissions from solid waste landfill (a) and wastewater treatment (b).

Figure 7. CO₂e emissions from the industrial process sector.

Figure 8. CO₂e emissions from different fuel types.

Figure 9. Total CE and different subsector CEs in Nanning city.

Table 2. Total CE, CEs per unit area, population, CEs per capita, GDP, CEs per GDP and the shares of primary, secondary and tertiary industries in Nanning city.

Year	CE (10^4 t-CO2e)	CE Per unit area (10^3t-CO2e /km^2)	Popu-lation (10^4 person)	CE Per-capita (t-CO2e/person)	GDP (10^8$)	CE Per GDP (t-CO2e/10^4$)	The primary indu-stry (%)	The secondary indu-stry (%)	The tertiary indu-stry (%)
1994	656	0.30	269	2.44	39.6	16.58	26.23	36.06	37.71
1995	776	0.35	273	2.84	48.08	16.15	26.09	34.26	39.65
1996	742	0.34	278	2.67	55.61	13.35	25.84	31.66	42.5
1997	752	0.34	281	2.68	66.29	11.35	25.81	30.29	43.9
1998	762	0.34	285	2.68	76.09	10.02	24.57	29.37	46.06
1999	799	0.36	286	2.8	79.89	10.01	23.88	28.57	47.55
2000	895	0.40	625	1.43	85.79	10.43	23.19	27.88	48.93
2001	949	0.43	630	1.51	97.78	9.7	21.7	27.06	51.24
2002	1079	0.49	635	1.7	107.14	10.07	20.37	27.11	52.52
2003	1675	0.76	642	2.61	111.45	15.03	19.11	29.2	51.69
2004	1906	0.86	649	2.94	123.69	15.41	17.39	31.23	51.38
2005	2012	0.91	660	3.05	143.76	14	17.07	31.76	51.17
2006	2231	1.01	672	3.32	175.43	12.72	16.4	33.78	49.82
2007	2603	1.18	684	3.81	214.72	12.12	16.34	34.18	49.48
2008	2786	1.26	692	4.03	263.42	10.57	15.38	34.68	49.94
2009	2975	1.35	698	4.26	321.93	9.24	13.93	34.59	51.48
2010	3381	1.53	707	4.78	375.09	9.01	13.58	36.21	50.21
2011	3748	1.69	711	5.27	433.34	8.65	13.82	37.51	48.67
2012	4681	2.12	713	6.56	524.82	8.92	12.9	38.38	48.72
2013	5257	2.38	724	7.26	617.39	8.52	11.84	38.95	49.21
2014	5353	2.42	730	7.34	693.43	7.72	11.27	39.75	48.98
2015	5544	2.51	740	7.54	769.47	6.92	10.88	39.45	49.67

Note:

The GDPs were converted to the PPP $ based on constant 2011 international values.

Figure 10. Electricity consumption-based CE (ECCE) containing commercial, household and industrial portions; electricity production-based CE (EPCE) was included in PHPS CE.

Table 3. Differences in four emission indicators in Nanning (NN), China (CN) and the world (WD).

Year	CE (Mt)			CE per capita (t-CO2e/person)			CE per GDP (t-CO2e/10^4$)			CE per unit area (10^3t-CO2e/km^2)
	NN	CN	WD	NN	CN	WD	NN	CN	WD	NN	CN	WD
1994	3.76	3029	23101	1.40	2.53	4.11	16.58	29.55	4.58	0.17	0.31	0.16
1995	4.83	3228	23564	1.77	2.67	4.13	16.15	25.90	4.52	0.22	0.34	0.16
1996	4.21	3323	24185	1.51	2.72	4.18	13.35	22.31	4.47	0.19	0.34	0.16
1997	4.02	3314	24423	1.43	2.68	4.16	11.35	19.16	4.34	0.18	0.34	0.16
1998	4.03	3312	24510	1.41	2.66	4.12	10.02	17.42	4.25	0.18	0.34	0.16
1999	3.65	3423	24853	1.28	2.72	4.12	10.01	16.96	4.16	0.18	0.36	0.17
2000	4.11	3514	25501	0.66	2.77	4.17	10.43	15.51	4.08	0.19	0.36	0.17
2001	4.46	3674	25825	0.71	2.88	4.17	9.70	14.25	4.03	0.20	0.38	0.17
2002	5.00	4025	26436	0.79	3.13	4.21	10.07	14.38	4.02	0.23	0.42	0.18
2003	7.73	4723	27718	1.21	3.65	4.36	15.03	16.19	4.06	0.35	0.49	0.19
2004	9.09	5521	29143	1.40	4.25	4.53	15.41	17.20	4.05	0.41	0.57	0.20
2005	9.83	6326	30279	1.49	4.84	4.65	14.00	17.23	4.02	0.44	0.66	0.20
2006	10.97	6926	31187	1.63	5.27	4.73	12.72	15.96	3.93	0.50	0.72	0.21
2007	13.74	7518	32307	2.01	5.69	4.84	12.12	14.23	3.86	0.62	0.78	0.22
2008	14.56	7663	32597	2.11	5.77	4.82	10.57	12.13	3.78	0.66	0.80	0.22
2009	16.32	8037	32004	2.34	6.02	4.68	9.24	11.01	3.72	0.74	0.83	0.21
2010	18.91	8472	33471	2.67	6.32	4.83	9.01	9.94	3.70	0.86	0.88	0.22
2011	21.88	9206	34413	3.08	6.83	4.91	8.65	9.70	3.66	0.99	0.96	0.23
2012	28.54	9415	34819	4.00	6.95	4.91	8.92	8.41	3.58	1.29	0.98	0.23
2013	32.14	9674	35312	4.44	7.11	4.92	8.52	7.58	3.52	1.45	1.00	0.24
2014	32.95	9761	35499	4.52	7.14	4.89	7.72	6.97	3.42	1.49	1.01	0.24
2015	33.13	9848	35686	4.48	7.16	4.86	6.92	6.35	3.33	1.50	1.02	0.24

Note:

The CO₂e emissions of China and the world were taken from the BP Statistical Review of World Energy, BP Global 2016.

Figure 11. Accumulative CE per capita of Nanning, China and World.

Table A1. CO₂e emission factors of different type’s energy.

Energy type	Carbon content (kg/GJ)^a	Carbon oxidation (%)^a	Emission rate (kg-CO2e/TJ)^a	Net calorific value (TJ/Gg)^a	Emission Factor (t-CO2e/t)
Crude coal	25.8	100	94600	20.9	1.977
Washed coal	25.8	100	94600	26.3	2.488
Other washed coal	25.8	100	94600	8.4	0.795
Briquette	26.6	100	97533	17.6	1.717
Coke	29.2	100	107067	28.2	3.019
Coke oven gas	12.1	100	44367	16726^b	7.421^c
Natural gas	15.3	100	56100	38931^b	21.840^c
Liquefied natural gas	17.5	100	64167	44.2	2.836
Crude oil	20.0	100	73333	42.3	3.102
Gasoline	20.2	100	74067	43	3.185
Kerosene	19.5	100	71500	44.1	3.153
Diesel	20.2	100	74067	43	3.185
Fuel oil	21.1	100	77367	40.4	3.126
Liquefied petroleum gas	17.2	100	63067	47.3	2.983
Other petroleum products	20.0	100	73333	40.2	2.948

Note:

^a The value was the IPCC recommended value.

^b The unit was KJ/m³.

^c The unit was t-CO₂e/10⁴m³.

Table A2. Emission factor of electricity (t-CO₂e/10⁴kwh).

Year	1994	1995	1996	1997	1998	1999	2000	2001	2002	2003	2004
Emission factor	9.012	9.030	8.994	8.958	8.922	8.886	8.850	8.835	8.820	8.805	8.790
Year	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015
Emission factor	8.670	8.620	8.220	7.970	7.900	7.580	7.640	7.700	7.760	7.820	7.733

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