Background
The Life Cycle Assessment (LCA) procedure depends on the allocation and system growth tenets. LCA is a methodical approach for evaluating the environmental effects of any product, service, or activity from conception through disposal. System expansion includes a product’s or system’s externalities in the assessment. At the same time, Allocation assigns a product’s or system’s environmental implications to its components or activities. In the framework of LCA, the ideas of allocation and system expansion will be defined, and their effects on the evaluation procedure will be covered. Since many impact allocation problems cannot be easily solved, the ISO standards for life cycle assessment leave a great deal of flexibility and can be applied in numerous ways. Various viewpoints are available for problems related to recycling and multifunctional processes.
What is Allocation Exactly?
Allocation is putting a product’s or system’s environmental impacts on its parts or activities. It is used in LCA when a product or system consists of several parts or processes. It is necessary to attribute each one’s environmental impacts to it. Allocation is a crucial step in LCA because it enables a precise assessment of the environmental effects of a system or product and may identify and address any potential environmental issues.
Economic Allocation and physical Allocation are the two types used in LCA. Physical Allocation is based on the physical inputs or outputs of the components or processes. In contrast, economic Allocation is based on the economic value of the components or processes. Depending on the assessment, economic Allocation or physical Allocation may be used.
The Allocation used in an LCA assessment depends on the evaluation’s scope. For instance, the economic allocation approach is often used to measure the environmental impacts of a particular product or service since it is more precise and accurate. However, physical Allocation may be more suitable if the assessment’s scope is broad and several commodities and services are being assessed since it is more suited to analyzing the environmental impacts of different goods and services.
Fundamentals of Allocation
Allocation means attributing environmental burdens during the life cycle for co-production, recycling, and disposal. However, since the emphasis up to now has been the solid scientific and technical techniques of Life Cycle Inventory (LCI):
- The validity of the fundamental laws of physics and chemistry
- Fundamental difficulties of science theory not yet addressed arise; efficiency metrics for technological facilities, agricultural practices, etc.;
- Clear and unmistakable cut-off standards.
For the first time, the boundaries of a rigorous scientific-technical analysis are breached when environmental burdens associated with manufacturing many goods simultaneously in a single unit process are assigned to the ‘higher’ portion of the product tree.
The best is this “Fair” Allocation. The primary goal is to equitably distribute the environmental load, consisting of inputs and outputs, to goods A and B. (generally A, B, C). The selection of the quality “fair” suggests that a rigidly scientific answer is impossible. The Allocation has been well-known in economics for over 150 years. It relates to distributing just prices among the items. The expenses for each product must be subtracted from the overall costs.
Allocation by Mass
Example 1 of Allocation by Mass
All inputs must be used in the Allocation per mass. The mass ratio of the co-products created determines how the outputs are divided. According to this criterion, 700/(700+300) = 0.7 emissions, energy consumption, supplementary materials, etc., and 30% B for an example unit process that produces two co-products (see Figure above) A and 300 kg B per functional unit. That’s crucial for many reasons.
Another Example is From the Chemical Industry as Below:
Example 2 of Allocation by Mass
In this example, the output is Sodium Hydroxide (NaOH) (52.3%), Chlorine (CL) (46.4%), and Hydrogen (H2) (1.3%). The main product is Sodium Hydroxide, and the other two are co-coproducts. In such a case, Allocation by mass or price can be performed among the product and the co-products.
System Expansion: What is it exactly?
System expansion is taking into account the externalities of a system or product while evaluating it. Externalities are environmental impacts that aren’t directly linked to how a system or product is made or used. Still, they nevertheless have the potential to influence the environment. Energy usage, pollution, and using land and water are externalities. System expansion is a crucial stage in LCA because it allows for a more detailed examination of the environmental effects of a system or product and may help identify potential environmental issues missed in the first evaluation.
By analyzing the environmental impacts of upstream and downstream operations such as raw material extraction, component manufacture, the transit of goods, and waste disposal, system expansion is often achieved in LCA. It is also crucial to consider how the use phase will affect the environment, including how much energy the product or system uses and the pollutants it produces. Considering a product or system’s externalities makes it possible to understand its environmental repercussions fully.
The ISO14044 and ISO14067 hierarchy also prescribes this as the first level. Nevertheless, the so-called avoided burdens require many assumptions in practice. Substitution, system expansion, and avoiding Allocation are standard terms to describe this consequential approach to multifunctionality.
Summary
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