Life Cycle Assessment (LCA) is a method that assesses the environmental impacts of products or systems. It is the recommended method for environmental display at the European level and standardized at the international level. This method is largely used because of its 3 main characteristics :

1. Functional: The object of study is defined by the function it fulfills. This allows a comparison between different solutions in order to choose the best one
2. Multi-criteria: Several environmental indicators are taken into account during the study. They include global warming potential, contribution to the depletion of abiotic and fossil resources, or the contribution of ionizing radiation. These indicators are among the main contributors to the impacts of digital technology.
3. Life-cycle approach: The impacts generated during all life cycle stages of the studied object are considered :
   
   • Extraction of raw materials: A lot of energy, chemicals and water are needed to extract materials from the earth and refine them. Furthermore, the concerned resources are limited and are getting rarer, thus it will be more and more difficult to extract them.
   • Manufacturing: During manufacturing, the raw materials are transformed into digital components and equipment. This consumes a lot of water and energy.
   • Distribution: Distribution represents the transport of the digital components from their place of fabrication to their place of use, mainly from Asia to Europe for IT equipment.
   • Use : The use of digital devices represents the energy consumed whilst using them.
   • End-of-life : This step concerns the disposal of the devices, either recycled, buried or burnt.

The LCA methodology is defined by ISO standards, in particular, ISO 14040 ¹⁾ and ISO 14044 ²⁾. Standard ISO 14040 describes the main principles of an LCA and is fairly general. Standard ISO 14044 sets out the requirements and guidelines in greater detail.

The LCA methodologies defined in ISO 14040 and 14044 are designed for general use. This is why there are many different LCA methods that comply with these standards. For Naknow, we chose the PEF 3.0 method ³⁾ and its 16 environmental indicators. According to ADEME ⁴⁾, the six most important are:

Parametric LCA extends traditional Life Cycle Assessment by replacing fixed input flows with adjustable parameters.

Rather than collecting inventory data directly, it infers it from sensitivity & usable parameters making it a hybrid of parameterization techniques and conventional LCA methodology.

The core advantage of this approach lies in its reusability: once the parametric model is built for a given product category, it can be applied to any number of products within that category without starting from scratch. This makes it significantly faster to update than classical LCA, which is a particularly valuable trait in fast-moving sectors like ICT. In essence, parametric LCA trades some granularity for a much leaner workflow — a deliberate trade-off calibrated to the level of accuracy that actually matters for the decisions at hand. Compared to classical LCA, it operates on simplified models that can represent an entire product range through a single automated framework, with inventory data derived from interpretable parameters rather than collected individually. This approach proves especially valuable in three contexts: * Comparing similar products, since the shared model structure inherently ensures methodological consistency across comparisons * Identifying eco-design levers, by revealing which parameters most significantly drive environmental impacts * Supporting decision-making, by delivering relevant environmental insights more efficiently ===== LCA for Naknow ===== ==== Methodology for components ==== Fonctional unit: Specific to each model.
System boundaries: Specific to each model. Approach: For each component, an expert database is created. This database includes a review of the current state of the art regarding the various types of technologies available for each component, as well as a review of the current state of environmental data. It also includes a description of the manufacturing processes for the components, based on their respective technologies. Life stages covered: Extraction of raw materials, manufacturing. ==== naKnow's parametric LCA model ==== For each component, the methodology applied in naKnow is as follows. First, a parametric LCA model is built based on existing literature. Experimental work is then carried out to refine this model. These experiments allow us to correct the material composition of components, but do not provide information on manufacturing processes. The approach is therefore a combination of bottom-up and top-down methods. <figure center |naknowmodel> <caption> naKnow parametric model </caption> </figure> ===== Bibliography =====