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A concept dating back to the 60s, at the genesis of Life Cycle Assessment (LCA), embodied energy is still a measurement scale widely used in certain sectors of activity, and forms the basis of many environmental impact measurement systems. Sometimes placed in competition with the carbon footprint, these two methodologies are evolving in parallel and can prove complementary.
What is embodied energy ? How is it measured? What and who does it help?
At the origin of embodied energy
The term "embodied energy" first appeared in 1972 in the research work of Dr Ian Boustead. The concept was the subject of several studies in the late 60s. Faced with the accumulation of waste and the massive exploitation of natural resources during a period of strong economic growth, many companies began to take an interest in the notion of product life cycles.
One of the first was Coca Cola, which in 1969 sought to identify less polluting alternatives to its glass bottle. The result, paradoxical as it may seem today, was that the plastic bottle required far less embodied energy than the glass one. This goes some way to explaining the near-universal use of this format from the 90s onwards.
What is embodied energy ?
Embodied energy corresponds to the total quantity of primary energy consumed throughout a product's life cycle, from the extraction of raw materials to its end-of-life. It is expressed in kWh.
This concept is designed to calculate the overall environmental impact of a product or material.
It therefore takes exhaustive account of the extraction of raw materials, transport, successive transformations, marketing, commissioning, use of the product and finally its recycling or destruction.
It is also known as embodied energy, or indirect energy, in the sense that it is not perceived by the consumer of the product or material. It is thus opposed to use energy, which is the energy consumed when the product is used (for example, the petrol you put in your internal combustion car or the heating of a building).
Embodied energy is particularly useful in certain sectors, such as construction or household appliances. It can be used to draw up a balance sheet of the energy required to produce a building or machine, and then to estimate when its construction has "paid for itself". In other words, its direct energy consumption has surpassed its consumption of embodied energy. According to this methodology, the longer a product's lifespan, the more likely it is to "pay for itself" in terms of its environmental impact, and thus avoid wasting energy.
Taking this subject into account seems all the more important as it is estimated that embodied energy represents, on average, ⅔ of a product's total energy consumption.
Calculating its quantity would therefore enable you to know, for example, whether it's better to buy a new electric vehicle or keep your old gasoline-powered jalopy.
Embodied energy and LCA
The concepts of embodied energy andLCA are interconnected. The term embodied energy was coined in connection with research into the life cycle of products. However, it was studies on embodied energy that subsequently led to the formalization and standardization of life cycle assessments.
Product lifecycle analysis is a standardized, controlled method for quantifying the embodied energy of a product or service. The concept was first introduced at the Rio Earth Summit in 1992.
This methodology was then processed by the International Organization for Standardization (ISO), which created new standards, ISO 14040 and 14044, for measuring the LCA of products and services.
Use case example: construction
Embodied energy has become a relatively common order of magnitude in the construction sector. It is used to measure the environmental impact of a building, and is the source of many innovations, both in the choice of materials and in the construction process.
A building's embodied energy includes, in particular:
- The energy used to manufacture building materials.
- The energy used to transport materials to the site.
- The energy used to construct the building.
- Energy used to maintain the building.
- The energy used to demolish the building.
Then there's the transportation of the workers, the setting up of the site, etc...
Since a building logically has a particularly long lifespan, it is estimated that embodied energy represents on average 20% of the total energy consumed over its lifetime, which still represents a substantial share of its environmental footprint.
Possible solutions for reducing this amount of energy include those that focus on materials (sustainable, low environmental impact, local to reduce transport) and those that concern building design (eco-responsible construction practices, energy-efficient buildings).
With this in mind, AFNOR has developed the HQE label, which aims to "limit the short- and long-term environmental impact of a construction or renovation project, while providing occupants with healthy and comfortable living conditions" . This label is based on studies of embodied energy buildings, and takes into account, among other criteria, the energy that will be consumed throughout the life of the building.
The limits of embodied energy
While embodied energy is intended to measure the "global" impact of a product or service throughout its life cycle, its focus on energy limits the analysis, as it does not take into account other co-impacts on certain environmental indicators.
Pollution, the forgotten issue of embodied energy
One of the main limitations of this methodology is thatit omits collateral environmental damage that may be linked to the product's life cycle.
As such, it does not take into account chemical pollution linked to the extraction of raw materials, their transformation or the end-of-life of products. This is the case, for example, with red mud generated during the aluminum manufacturing process.
The case of Coca-Cola is particularly telling. As we said, their initial analyses in the late 60s were part of the criteria that led them to favor the PET bottle, which consumes less embodied energy than its glass ancestor. Unfortunately, this initiative also led them to become the world's leading source of plastic pollution, according to the latest reports from the NGO Break Free From Plastic.
However comprehensive and elaborate, embodied energy is not a sufficient indicator to measure the full environmental impact of a product. Other indicators will have to be added to measure the collateral damage generated during a product's life cycle.
A complex indicator to measure
Taking into account the entire life cycle of a product, building or service, embodied energy is difficult to measure. This is all the more true in the case of complex products made up of a wide variety of components.
The automotive industry is a prime example. Thousands of parts, from many different sources, made from materials that have been transformed many times.
Added to this complexity is the issue of product end-of-life. Which components of a complex product can be recycled or reused, and which will have to be destroyed? Does the end-of-life site have the necessary resources for recycling?
While it is possible to establish an average, the sheer number of criteria to be taken into account makes the results of this analysis relatively uncertain, and therefore requires a strict, standardized process as well as the willingness to act of all the players involved in a product's life cycle.
How to reduce embodied energy ?
As we've already mentioned, embodied energy represents on average ⅔ of a product's energy consumption. To reduce our negative impact on the environment, we therefore need to take this subject head on.
As the amount of energy consumed is strongly linked to the production of new products, we need to rethink our consumption patterns. Both in the quantity of products and in the way they are produced.
So we need to find a way of making this energy "profitable". Reducing the ratio of embodied energy consumption to energy consumption over the lifetime of a product.
Extend product life
One of the first ways to reduce the amount of energy consumed is toincrease the lifespan of products. In fact, a product in working order will not (or should not) have to be replaced.
Increasing the life of products by combating programmed obsolescence or increasing their reparability can significantly reduce their environmental impact.
Then there's the question of whether it's better to replace a product that consumes a lot of energy in use with a new, more energy-efficient product. The most complex products require a large quantity of embodied energy to manufacture, so replacing them with a more energy-efficient product is not always the best solution. Sometimes it's better to maximize the use of the current product.
Reduce energy consumption at source
The more a product is processed, the more it consumes embodied energy. The further a product comes from, the more it will consume embodied energy.
By favoring raw materials, or at the very least less processed materials, we can considerably reduce the amount of energy consumed in the manufacture of a product. This is the case, for example, in the construction industry, where flax fibre insulation is far less damaging to the environment than polystyrene.
Similarly, using local products eliminates a large part of the embodied energy of a product, linked to the transportation of materials.
Embodied energy and globalization
The embodied energy analysis has highlighted some of the mirages of decarbonization when studied within a restricted perimeter.
Over the last few decades, developed countries have tended to export their embodied energy to developing countries.
The relocation of whole sections of European industry to Asia has led to a de facto relocation of our energy consumption, artificially reducing the official figures for territorial emissions in European countries. China has thus become the world's leading exporter of embodied energy.
We therefore have a skewed view of our carbon emissions efforts. While our direct emissions are decreasing, our consumption of embodied energy tends to increase. This is due to our consumption patterns (more products, lower quality), but also to the origin of the products we consume, with the transport of goods having a major impact on the amount of energy needed to obtain the product.
Conclusion
While embodied energy remains a valuable indicator for assessing the environmental impact of products and services, its use needs to be complemented by other tools enabling a more comprehensive assessment, taking into account chemical pollution and ecosystem degradation.
Reducing our dependence on embodied energy requires concerted action at all levels of society, from product design to consumer habits, in order to promote sustainable development that respects the environment. Finally, it is essential to take these actions on a global scale. A global, collaborative approach is needed to tackle these challenges and move towards a more responsible use of resources.
Sources :
- "Branded 6 - The brand audit report 2023"Break Free from Plastic, 01/02/2024
- "Embodied energy : what does it mean?, Alexia Lalanne, Choisir.com, 14/09/2020
- "History of LCA", Eco-design cluster, 04/01/2018
- "Embodied energy : the hidden energy of everyday products"GEO, 30/01/2017
- "Imported emissions - The stowaway of global trade"Climate Action Network, Ademe and Citepa, 01/05/2013
- "L'énergie grise des matériaux et ouvrages"Les Guides Bio-Tech, Institut pour la Conception Ecoresponsable (ICEB) and Agence régionale énergie - climat Île-de-France (ARENE), 29/11/2012
- "Embodied energy : an invisible energy to be taken into account", Calculeo
