Comparison of carbon footprints of steel versus concrete pipelines for water transmission

Figures & data

Figure 1. U.S. pipe materials usage (CURIE, 2013).

Table 1. Embodied energy coefficients for pipe component materials (Hammond and Jones, 2011).

Pipe component material	Embodied energy coefficient
	MJ/kg	kWh/lb
Steel pipe (world average recycled content 39%)	24.90	3.14
Concrete (5000 psi)	0.95	0.12
Cement mortar (1:3 cement:sand mix)	1.33	0.17
Prestressed steel wires	36.00	4.54

Table 2. Embodied energy and CO₂ emissions for pipe segments, steel pipe vs. PCCP.

Parameter	Subparameter	Unit	Pipeline segment								Total
			A	B	C	D	E	F	G	I
Segment length		ft	220,394	26,159	329,388	114,131	8,517	57,768	7,120	14,765	778,242
Pipe section diameter		inches	84	108	108	84	72	66	108	84	N/A
Steel pipe	Embodied energy per foot	kWh/ft	899	1607	1607	899	770	706	1607	899	N/A
	Embodied energy—total segment	10^6 kWh	198.3	42.1	529.6	102.7	6.6	40.8	11.4	13.3	944.8
	Wsteel	lb/ft	280	503	503	280	240	220	503	280	N/A
	Wcement	lb/ft	129	165.70	165.70	129	110.72	101.56	165.70	129	N/A
	CO2 emissions	short tons	113,725	24,144	303,726	58,898	3,785	23,399	6,538	7,628	541,843
		lb/ft	1032	1846	1844	1032	889	810	1836	1033	1392
PCCP	Embodied energy per foot	kWh/ft	794	1058	1058	794	528	478	1058	794	N/A
	Embodied energy—total segment	10^6 kWh	175.0	27.7	348.8	90.7	4.5	27.7	7.5	11.7	693.6
	Wsteel	lb/ft	56.11	71.66	71.66	56.11	48.45	44.3	71.66	56.11	N/A
	Wcement	lb/ft	341.73	442.49	442.49	341.73	309.25	285.26	442.49	341.73	N/A
	Wconcrete	lb/ft	1516.16	2612.38	2612.38	1516.16	1312.54	1148.15	2612.38	1516.16	N/A
	Wsteel wire	lb/ft	83.26	98.05	98.05	83.26	36.67	33.78	98.05	83.26	N/A
	CO2 emissions	short tons	100,363	15,886	200,037	52,016	2,581	15,886	4,301	6,710	397,780
		lb/ft	911	1215	1215	912	606	550	1208	909	1022

Figure 2. Pipe cross sections: (a) steel and (b) PCCP.

Table 3. Diesel fuel required and CO₂ emissions for pipe transportation, steel pipe vs. PCCP.

Parameter	Subparameter	Unit	Pipeline segments								Total
			A	B	C	D	E	F	G	I
Segment length		ft	220,394	26,159	329,388	114,131	8,517	57,768	7,120	14,765	778,242
Pipe section diameter		inches	84	108	108	84	72	66	108	84	N/A
Steel pipe	Pipe section weight	lb.	13,979	25,153	25,153	13,979	11,974	10,972	25,153	13,979	140,342
	Pipe section length	ft	50	50	50	50	50	50	50	50	N/A
	Number of pipe sections = number of truck trips	number	4,408	523	6,588	2,283	170	1,155	142	295	15,564
	Distance from production plant to segment center	miles	240	228	162	54	222	234	72	58	N/A
	Diesel required for truck–trailer round trips	gallon	182,404	20,604	185,189	21,278	6,546	46,645	1,801	3,014	467,481
	CO2 emissions	short tons	2,025	229	2,056	236	73	518	20	33	5,190
		lb/ft	18.4	17.5	12.5	4.1	17.1	17.9	5.6	4.5	13.3
PCCP	Pipe section weight	lb	39,945	51,593	51,593	39,945	40,961	24,184	51,593	39,945	339,759
	Pipe section length	ft	16	20	20	16	24	16	16	20	N/A
	Number of pipe sections = number of truck trips	number	13,775	1,308	16,470	7,134	355	3,611	445	739	43,837
	Distance from production plant to segment center	miles	150.2	182.2	116.6	73.8	173.8	169.2	57.6	56.4	N/A
	Diesel required for all truck–trailer round trips	gallon	286,961	51,601	415,446	72,822	10,650	105,875	4,450	7,265	955,070
	CO2 emissions	short tons	3,186	573	4,612	808	118	1,175	49	81	10,602
		lb/ft	28.9	43.8	28.0	14.2	27.7	40.7	13.8	11.0	27.2

Table 4. Hours of construction equipment needed and CO₂ emissions for installation of steel pipe.

			Duration	Fuel consumption	CO2 emissions
Activity	Quantity needed for the project	Productivity per hour	(hr)	(1000 gal)	Short tons	lb/ft	%
Excavation, bcy	6,484,293	68.03	95,315	797.8	8,855.4	22.4	33.0
Trench support, feet	778,242	30.5	25,516	213.6	2,370.6	6.0	8.8
Pipe laying, feet	778,242	138.37	5,624	47.1	522.5	1.3	1.9
Backfilling, lcy	6,762,888	96.47	70,104	586.8	6,513.2	16.4	24.2
Compaction, lcy	6,762,888	3,024.19	2,236	18.7	207.7	0.5	0.7
Material handling, lcy	6,762,888	310.70	21,767	182.2	2,022.3	5.1	7.5
Material screening, lcy	6,762,888	321.59	21,030	176.0	1,953.8	4.9	7.2
Water sprinkling, lcy	6,082,086	228.69	26,595	222.6	2,470.9	6.2	9.1
Sweeping, ft^2	116,736,300	5,604.09	20,831	174.4	1,935.3	4.9	7.1
Total			289,018	2419.1	26,852	67.8	100

Note: bcy = bank cubic yard and lcy = loose cubic yard.

Table 5. Hours of construction equipment needed and CO₂ emissions for installation of prestressed concrete cylinder pipe (PCCP).

Activity	Amount needed for the project	Productivity per hour	Duration	Fuel consumption	CO2 emissions
			(hr)	(gal)	Short tons	lb/ft	%
Excavation, bcy	6,159,634	68.03	90,543	757.8	8,412.1	21.2	30.9
Trench support, feet	778,242	16.00	48,640	407.1	4,519	11.4	16.6
Pipe laying, feet	778,242	70.00	11,118	93.1	1,032.9	2.6	3.8
Backfilling, lcy	5,813,336	96.47	60,261	504.4	5,598.7	14.1	20.6
Compaction, lcy	5,813,336	3,024.19	1,922	16.1	178.6	0.5	0.7
Material handling, lcy	5,813,336	310.70	18,710	156.6	1,738.3	4.4	6.4
Material screening, lcy	5,813,336	321.59	18,077	151.3	1,679.5	4.2	6.1
Water sprinkling, lcy	5,074,435	228.69	22,189	185.7	2,061.5	5.2	7.6
Sweeping, ft^2	116,736,300	5,604.09	20,831	174.4	1,935.3	4.9	7.1
Total			292,291	2446.5	27,156	68.6	100

Note: bcy = bank cubic yard and lcy = loose cubic yard.

Table 6. Energy consumption and CO₂ emissions for pipeline operation, both steel and PCCP.

Value	Year 2020–2030	Year 2030–2040	Year 2040–2050	Year 2050–2060	Total 2020–2060
Average annual energy consumption (kWh)	160,753	124,103	165,534	165,544	N/A
Total energy consumption (kWh)	1,607,528	1,241,028	1,655,342	1,655,442	6,159,340
Total CO2 emissions (short tons)	922	712	949	949	3532
Total CO2 emissions (lb/ft)	2.3	1.8	2.4	2.4	8.9

Figure 3. CO₂ emissions for different phases for steel pipe and PCCP.

Figure 4. Energy consumption for material production and pipeline fabrication for steel and PCCP.

Table 7. Life-cycle CO₂ emission summary for steel pipe and PCCP.

	Steel pipe CO2 emissions			Prestressed concrete cylinder pipe (PCCP) CO2 emissions
Life-cycle phase	Short tons	lb/ft	%	Short tons	lb/ft	%
Manufacturing and fabrication	541,843	1392	93.9	397,780	1022	90.7
Transportation	5,190	13	0.9	10,602	27	2.4
Installation	26,531	67	4.6	26,763	68	6.1
Operation	3532	8.9	0.6	3532	8.9	0.8
Total	577,096	1,481	100	438,677	1,126	100

Hammond, G., and C. Jones. 2011. Inventory of Carbon and Energy (ICE), Version 2.0. Sustainable Energy Research Team. Department of Mechanical Engineering, University of Bath. www.bath.ac.uk/mech-eng/sert/embodied

 Google Scholar