Life Cycle Assessment | Chemistry for Grade 10 PDF Download

About Life Cycle Assessment

A life-cycle assessment or LCA is a 'cradle to grave' analysis of the impact of a manufactured product on the environment. There are many detailed stages but the main ones are:

1. extracting and processing the raw materials needed
2. manufacturing the product and its packaging
3. using the product during its lifetime
4. disposing of the product at the end of its useful life

The Four Main Stages

At all stages, an LCA is likely to include information about the use of energy, transport of materials and the release of waste substances into the environment.

1. Raw materials

All the raw materials we need come from the Earth's crust, atmosphere or oceans, or are due to living organisms. Obtaining these materials has an impact on the environment, including:

• using up limited resources such as ores and crude oil
• damaging habitats through quarrying, mining, or felling trees

2. Manufacture

The manufacture of products has an impact on the environment, including:

• using up land for factories
• the use of machines and people

3. Use

The impact of a product on the environment during its use depends on the type product. For example, a wooden chair has very little impact, unless it needs cleaning or repair. On the other hand, using a car will have a significant impact.

4. Disposal

The disposal of old products has an impact on the environment, including:

• using up land for landfill sites
• whether any or all of the product can be recycled or reused
  
  Four main stages of the life-cycle assessment

Example: The table shows some data about the energy needed in the lifetime of a pillow case.
Discuss the use of energy during the lifetime of the pillowcase. Describe one way in which the energy use could be significantly reduced.

One quarter of the energy use is associated with making the pillowcase, and very little in disposing of it. The greatest use of energy happens when it is being used, probably because of washing, drying and ironing the pillowcase. Energy use could be reduced by drying it outside and without ironing it, and washing it at a lower temperature.

Comparative LCAs

Comparative LCAs can be used to evaluate which of two alternative products will have a lower negative impact on the environment. For example, we can compare plastic carrier bags and paper carrier bags:

Criticisms of LCAs

• It is sometimes easy to work out accurate numerical values for parts of a LCA. For example, we can measure the amount of energy needed to manufacture a product, or the amount of carbon dioxide produced by transporting raw materials. However, some parts of a LCA require judgements, such as the effect of pollutants. This means that completing a LCA is not a totally objective process, and different people might come up with different judgements.
• It is important to consider who has completed the LCA and whether they have any bias. For example, if the LCA is completed by the company which is making and selling a product, they might only include some parts of the genuine environmental impact.