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C10 B) Life Cycle Assessment
C10 B) Life Cycle Assessment
A life cycle assessment (LCA) looks at the total impact that a product has on the environment during the whole life of the product. There are 4 main different aspects to an LCA, which are:
There are many different parts within each of the 4 different aspects of an LCA, such as the effect on the environment, the amount of energy used, the waste products created etc. Let’s have a look at the 4 different stages in more detail.
- Extraction and processing of the raw materials
- Manufacturing and packaging
- Using the product
- Disposing of the product
There are many different parts within each of the 4 different aspects of an LCA, such as the effect on the environment, the amount of energy used, the waste products created etc. Let’s have a look at the 4 different stages in more detail.
1. Extraction and Processing of the Raw Materials
The raw materials for products are obtained from resources on the earth. The extraction and processing of these resources has a variety of different environmental impacts.
For example, most metals come from metal ores that are extracted by mining. The mining of ores has quite a few negatives as it scars the landscape/ destroys habitats (especially if it is open cast mining), uses vast quantities of energy and produces a lot of waste. After the ore has been extracted, it then needs to be processed to obtain the pure metal that we desired. This requires large quantities of energy (which can produce a lot of greenhouse gases) and produces quite a lot of waste products that need to be disposed of appropriately.
Also, some of the resources that we extract will be finite, which means that there is a fixed supply of that resource. The extraction of a finite resource will result in there being less of the resource available for future generations.
The raw materials for products are obtained from resources on the earth. The extraction and processing of these resources has a variety of different environmental impacts.
For example, most metals come from metal ores that are extracted by mining. The mining of ores has quite a few negatives as it scars the landscape/ destroys habitats (especially if it is open cast mining), uses vast quantities of energy and produces a lot of waste. After the ore has been extracted, it then needs to be processed to obtain the pure metal that we desired. This requires large quantities of energy (which can produce a lot of greenhouse gases) and produces quite a lot of waste products that need to be disposed of appropriately.
Also, some of the resources that we extract will be finite, which means that there is a fixed supply of that resource. The extraction of a finite resource will result in there being less of the resource available for future generations.
2. Manufacturing & Packaging
The manufacturing and packaging of products uses lots of resources, energy and can produce pollution; all of these have negative implications for the environment. Furthermore, the manufacturing and packaging can produce waste products. Some of these waste products will be useful for other industries and some of the waste products will be harmful to the environment if they are released into the environment (we will need to ensure that these harmful waste products are disposed of safely into the environment).
Also, the manufacturing and packaging process usually involves large factories, which means that land will need to be cleared for the factories (a forest may have to be chopped down so that a factory can be built). Also, the factories will use machinery that needs to be made and the machinery will use energy and resources.
The manufacturing and packaging of products uses lots of resources, energy and can produce pollution; all of these have negative implications for the environment. Furthermore, the manufacturing and packaging can produce waste products. Some of these waste products will be useful for other industries and some of the waste products will be harmful to the environment if they are released into the environment (we will need to ensure that these harmful waste products are disposed of safely into the environment).
Also, the manufacturing and packaging process usually involves large factories, which means that land will need to be cleared for the factories (a forest may have to be chopped down so that a factory can be built). Also, the factories will use machinery that needs to be made and the machinery will use energy and resources.
3. Using the Product
The effect that using a product has on the environment depends on the product and how long the product is used for.
Let’s have a look at a petrol car. Whilst a petrol car is being driven, it is burning petrol which produces carbon dioxide, carbon monoxide, sulfur dioxide and nitrogen oxides. All of these products produced have negative effects on the environment. The carbon dioxide that is produced will contribute to the enhanced greenhouse effect, the carbon monoxide will affect the haemoglobin in red blood cells, and the sulfur dioxide and nitrogen oxides will cause acid rain.
Another product would be a glass cup. Whilst the glass cup is used, it will have a very small impact on the environment.
The length of time that a product is used for also has an influence in this section. For example, a glass cup that can be used multiple times will have a smaller impact on the environment over the whole course of its life than a single use paper cup that can only be used once.
The effect that using a product has on the environment depends on the product and how long the product is used for.
Let’s have a look at a petrol car. Whilst a petrol car is being driven, it is burning petrol which produces carbon dioxide, carbon monoxide, sulfur dioxide and nitrogen oxides. All of these products produced have negative effects on the environment. The carbon dioxide that is produced will contribute to the enhanced greenhouse effect, the carbon monoxide will affect the haemoglobin in red blood cells, and the sulfur dioxide and nitrogen oxides will cause acid rain.
Another product would be a glass cup. Whilst the glass cup is used, it will have a very small impact on the environment.
The length of time that a product is used for also has an influence in this section. For example, a glass cup that can be used multiple times will have a smaller impact on the environment over the whole course of its life than a single use paper cup that can only be used once.
4. Disposing of the Product
At the end of a product’s life, the product is generally disposed of in landfill sites. These landfill sites require space and the products in the landfill sites may pollute the surrounding environment (batteries should not be disposed of in landfill sites because the lead, cadmium and mercury can poison people and animals and contaminate the soil and water).
Also, energy is required to transport these products to landfill sites, which will cause more pollutants to enter the environment.
The effects of disposing of products can be reduced if we recycle or reuse any parts of the products. We will be looking at recycling and reusing in the next section.
At the end of a product’s life, the product is generally disposed of in landfill sites. These landfill sites require space and the products in the landfill sites may pollute the surrounding environment (batteries should not be disposed of in landfill sites because the lead, cadmium and mercury can poison people and animals and contaminate the soil and water).
Also, energy is required to transport these products to landfill sites, which will cause more pollutants to enter the environment.
The effects of disposing of products can be reduced if we recycle or reuse any parts of the products. We will be looking at recycling and reusing in the next section.
Comparison of LCAs
We are now going to have a look at a comparison of LCAs for a plastic and paper bag. The analysis for the 4 different aspects of LCAs is shown below.
We are now going to have a look at a comparison of LCAs for a plastic and paper bag. The analysis for the 4 different aspects of LCAs is shown below.
1. Extraction and Processing of the Raw Materials
Plastic bags are made from crude oil which is a finite resource (it will run out one day). Fractional distillation, cracking and polymerisation are required to make a bag and all of these different processes require a lot of energy. The waste fractions from the fractional distillation of crude oil can be used for other uses.
Paper bags can be made from recycled paper or paper that has come from new trees. Obtaining the paper from recycled paper or new trees requires less energy than obtaining the plastic for plastic bags.
2. Manufacturing and Packaging
It is cheaper to make large quantities of plastic bags than paper bags. This is because the handles must be glued onto paper bags.
3. Using the Product
There is a smaller impact on the environment for plastic bags because plastic bags can be used for a longer period of time compared to paper bags. This is because plastic bags tend to be stronger and are able to deal with becoming wet; whereas paper bags are weaker and tend to break when they become wet.
However, it does depend on how many times the bag is used for. If an individual uses the bag once and then disposes of it, the LCA of the plastic bag will be very high.
4. Disposing of the Product
Plastic bags can sometimes be recycled if they are disposed of correctly. But, if they are sent to landfill, they will not breakdown as they are not biodegradable. This means that the plastic bags will be in landfill sites for hundreds of years and they will pollute the environment whilst they are there.
Paper bags can easily be recycled and made into new paper bags. Also, if the paper bags are sent to landfill sites, they will breakdown quickly as paper is biodegradable.
Comparison
From the two LCAs for both paper bags and plastic bags, we can see that it is quite tricky to say which type of bag has a smaller LCA. This is because it depends on how the bags are produced, how long they are used for and how they are disposed of. This means that we cannot say for certain which type of bag has a smaller LCA.
Plastic bags are made from crude oil which is a finite resource (it will run out one day). Fractional distillation, cracking and polymerisation are required to make a bag and all of these different processes require a lot of energy. The waste fractions from the fractional distillation of crude oil can be used for other uses.
Paper bags can be made from recycled paper or paper that has come from new trees. Obtaining the paper from recycled paper or new trees requires less energy than obtaining the plastic for plastic bags.
2. Manufacturing and Packaging
It is cheaper to make large quantities of plastic bags than paper bags. This is because the handles must be glued onto paper bags.
3. Using the Product
There is a smaller impact on the environment for plastic bags because plastic bags can be used for a longer period of time compared to paper bags. This is because plastic bags tend to be stronger and are able to deal with becoming wet; whereas paper bags are weaker and tend to break when they become wet.
However, it does depend on how many times the bag is used for. If an individual uses the bag once and then disposes of it, the LCA of the plastic bag will be very high.
4. Disposing of the Product
Plastic bags can sometimes be recycled if they are disposed of correctly. But, if they are sent to landfill, they will not breakdown as they are not biodegradable. This means that the plastic bags will be in landfill sites for hundreds of years and they will pollute the environment whilst they are there.
Paper bags can easily be recycled and made into new paper bags. Also, if the paper bags are sent to landfill sites, they will breakdown quickly as paper is biodegradable.
Comparison
From the two LCAs for both paper bags and plastic bags, we can see that it is quite tricky to say which type of bag has a smaller LCA. This is because it depends on how the bags are produced, how long they are used for and how they are disposed of. This means that we cannot say for certain which type of bag has a smaller LCA.
Criticisms of LCAs
Some aspects of LCAs are easy to quantify. For example, we can easily work out a numerical value for the amount of energy that is used to extract and manufacture a product. However, it is considerably harder to put a numerical value for the pollution that is caused during the life of a product – what value do we place on the amount of carbon dioxide produced during the product’s life, or the negatives of a plastic bag being dumped in a ditch on the side of a road.
If two assessors completed an LCA for a product, we would expect the LCAs to be different. This is because the assessors will make different assumptions about the product. The different assumptions could be about the amount of time that the product is used for; if the product is a car, is the car used for 80,000 miles or 180,000 miles? Another different assumption could be how the product is disposed of; if the product is a plastic bag, is the plastic bag recycled or is the plastic bag thrown into a hedge row next to a field where it will stay for many years? These different assumptions will lead to different impacts and therefore, different values for LCAs.
Also, with LCAs, it is important to look at who has carried out the LCA and whether there is any bias in their LCA. For example, with plastic bags, an LCA written by a plastic bag manufacturer would probably undervalue the negatives of plastic bags, and an LCA written by an environmentalist would probably overvalue the negatives of plastic bags. This is why we need to be very careful with LCAs as their outcomes often depend on who has written them.
Some aspects of LCAs are easy to quantify. For example, we can easily work out a numerical value for the amount of energy that is used to extract and manufacture a product. However, it is considerably harder to put a numerical value for the pollution that is caused during the life of a product – what value do we place on the amount of carbon dioxide produced during the product’s life, or the negatives of a plastic bag being dumped in a ditch on the side of a road.
If two assessors completed an LCA for a product, we would expect the LCAs to be different. This is because the assessors will make different assumptions about the product. The different assumptions could be about the amount of time that the product is used for; if the product is a car, is the car used for 80,000 miles or 180,000 miles? Another different assumption could be how the product is disposed of; if the product is a plastic bag, is the plastic bag recycled or is the plastic bag thrown into a hedge row next to a field where it will stay for many years? These different assumptions will lead to different impacts and therefore, different values for LCAs.
Also, with LCAs, it is important to look at who has carried out the LCA and whether there is any bias in their LCA. For example, with plastic bags, an LCA written by a plastic bag manufacturer would probably undervalue the negatives of plastic bags, and an LCA written by an environmentalist would probably overvalue the negatives of plastic bags. This is why we need to be very careful with LCAs as their outcomes often depend on who has written them.