Copper cable or aluminum alloy cable, which is more environmentally friendly

In the wire and cable industry, in order to reduce costs, the practice of "aluminum section copper" or even "aluminum instead of copper" is feasible.

This paper will analyze which is more advantageous
, copper cable or aluminum alloy cable, from the aspects of wire and cable manufacturing cost and environmental impact in the whole life cycle process of power cable.

From the perspective of cable production costs, copper is heavier
than aluminum.
The specific gravity of copper is 8.
9g
.
cm3, the specific gravity of aluminum is 2.
7g/cm3, that is, in the case of the same conductor standard, the component of copper conductor is 3.
3 times
that of aluminum conductor.
The conductivity of aluminum metal is not as good as that of copper conductors, and the cross-section of aluminum conductors is 61%
larger than that of copper conductors in the case of the same transmission current.
If the cable is made from aluminum conductors, it is necessary to use aluminum conductors
with larger cross-sections.
Then the subsequent addition of insulation, sheath and armor materials of the aluminum core cable weakens the quotation advantage
of using aluminum conductors.

Taking a 70mm2 copper core cable as an example, the cost of the copper conductor accounts for about 65% of the cost of the entire cable, while the cost of the 120mm2 aluminum core cable with the same current carrying capacity can save 23.
5%.

If the cost of the copper conductor accounts for 80% of the cost of the entire cable, then the cost of the aluminum core cable with the same current carrying capacity can save up to 46%.

As long as the cost of the copper conductor in the cable drops to less than 50% of the cost of the entire cable, the aluminum core cable will lose its cost advantage
.
Today, the cost of most copper-core low-voltage cables and many medium-voltage cable conductors has exceeded 50%, so compared with copper-core power cables, the cost-saving advantages of aluminum core power cables are appropriately significant
.

Of course, except for a simple cost comparison, it does not explain the whole problem
.
In the context of the current increasingly complex business environment and increasing environmental pressure, the environmental impact of the whole life cycle of power cables has become a focus
of attention.

Life cycle assessment (LCA) first identifies and quantifies energy and material consumption and environmental releases throughout the life cycle phase, then evaluates the environmental impacts of these consumption and releases, and finally identifies and evaluates opportunities to
reduce these impacts.
LCA differs from other traditional evaluation methods in two notable ways
.
First, it is characterized by a whole-process characteristic, i.
e.
the evaluation of the environmental load or impact caused by the
system under study throughout its life cycle.
Secondly, it has the characteristics of comprehensiveness, considering not only the impact of waste on the environment, but also the comprehensive impact
on the environment caused by the consumption of resources and energy.

If we want to compare the life cycle environmental impact of copper cable and aluminum alloy cable, we must first establish basic comparison conditions, that is, the same ampacity, system boundary, function, environmental impact type, evaluation tool and the data collected from copper cable and aluminum alloy cable manufacturers
with similar production technology level and scale 。 Under this premise, five stages of raw material acquisition, product manufacturing, product use, transportation and waste disposal were selected as the system boundary of the two cables, and YJHLV82-4×185 (XLPE insulated PVC sheathed aluminum alloy with interlocking armored aluminum alloy power cable) and YJV224×120 (XLPE insulated steel strip armored PVC sheathed copper cable) were selected as comparison products according to the national standard GB50217 power engineering cable design code
。 The function is 1KM cable
.
The environmental impact types mainly include four main environmental impact types, including global warming potential, acidification potential, eutrophication potential and energy consumption, and the evaluation index systems
of CML2001 and EI99 are adopted respectively.

Through the evaluation analysis, the following five points
can be found.
1.
Types of
global warming environmental impacts.
Aluminum alloy cable has higher greenhouse gas emissions than copper cable in the manufacturing and use stage, lower than copper cable in the transportation and recycling stage, and close to copper cable in the raw material acquisition stage, slightly lower than copper cable
.
Second, the environmental impact
of acidification.
Aluminum alloy cable has higher emissions than copper cable in the manufacturing and use stages, and slightly lower emissions than copper cables
in the raw material acquisition, transportation and recycling stages.
Third, the environmental impact
of eutrophication potential.
Aluminum alloy cable has higher emissions than copper cable in the manufacturing and use stages, and slightly lower emissions than copper cables
in the raw material acquisition, transportation and recycling stages.
Fourth, the environmental impact
of energy consumption.
Aluminum alloy cables consume more energy than copper cables in the raw material acquisition, manufacturing and use stages, and slightly lower than copper cables
in the transportation and recycling stages.
5.
Overall environmental impact
.
Copper cables are superior to aluminum alloy cables
.

The main contribution of the life cycle environmental impact of power cable products comes from the use stage of the cable, accounting for more than 98% of the environmental impact contribution rate, the service life calculated in the use stage is 30 years, the power loss generated is relatively huge, and the use scenario of the cable has a direct relationship, different use scenarios and different service life will greatly affect the calculation results
.
Secondly, the raw material acquisition stage of the product accounts for about 1%, and the smallest contribution is the transportation stage of the product, accounting for less than 10,000
.

Through this result, it can be found that reducing power loss in the transmission process is the most important, effective and practical means
to reduce the environmental impact of the power cable life cycle.
Power factor is an important technical and economic indicator of the power supply system, electrical equipment in the consumption of active power at the same time, but also need a large amount of reactive power by the power supply to the load, power factor reflects the electrical equipment in the consumption of a certain active power at the same time required reactive power, user power factor level, for the power system generation, supply, power equipment full use, has a significant impact
.
Appropriately improving the power factor can not only give full play to the production capacity of power generation, supply and power equipment, reduce line loss, improve voltage quality, but also improve the work efficiency of
user equipment.

At the same time, reasonable configuration of conductor cross-section, additional line circuit, additional reactive power compensation equipment and strengthening management measures can reduce line loss to varying degrees, thereby reducing the environmental impact
of power cables in the use stage.
In this regard, copper cables are significantly superior to aluminum alloy cables
.
At the same time, there is still a problem of the utilization of recycled raw materials in the power cable industry, and the replacement of virgin material processes by different recycled metal materials will have different environmental impacts
.

Power cable manufacturers can start from the conductor itself and improve the production process, further improve the metal purity and alloy process, increase the conductivity of the conductor, narrow the gap with developed countries, and reduce reactive power consumption
.
At the same time, it can also reduce the power cable and environmental impact
as much as possible from the aspects of raw material selection, reducing production energy consumption, reducing transportation distances and product recycling.