Use stage in Luminaire Life Cycle Assessment GREENLIGHT ALLIANCE IRENE MAZZEI, PHD.
In this issue the GreenLight Alliance focuses its attention on a fundamental characteristic of lighting products: their use and the environmental impacts associated with it.
In previous issues we have highlighted the need to have consistent and standardised rules to follow for the calculation of environmental impacts through Life Cycle Assessment; but how can we apply standard rules to describe the use of luminaires, when this is generally defined by the final application of the product? How do we protect the efforts to harmonise rules and at the same time allow flexibility for designers and practitioners to assess specific projects? Introduction The use stage is often shown as a hotspot in the life cycle of a luminaire, due to the main function of these products being related to the consumption of energy to produce artificial light. However, the attention dedicated to the concept of embodied impacts of products in the built environment has recently highlighted the potential relevance of embodied impacts in the life cycle of products. Acknowledging the efforts invested in: • Decarbonising national electricity supply. • Increasing the efficiency of light sources through technological advancement. • Growth and improvement of smart controls. • Building standards encouraging a move away from ‘design for compliance to design for performance’. • Legislative push for efficiency.
148 / 149
It is reasonable to assume that the relative importance of in-use impacts over embodied impacts will progressively decrease. Nevertheless, the impact of the use stage will likely still be associated with a non-negligible portion of the environmental burdens in luminaires. However, when evaluating in-use impacts of luminaires, one must first define the use conditions before drawing any conclusions on the relative importance of operational impacts over embodied impacts. Some products may be used in applications which need them on permanently, some others may be connected to control systems. This will naturally affect the energy consumed by the product. The Life Cycle Assessment (LCA) methodology, widely used worldwide to evaluate environmental impacts of products and services, is able to capture the burdens associated with the use stage of products. The impacts deriving from electricity consumption during the use of products are typically indicated with the life cycle stage B6, as shown in Figure 1. The impacts associated with the use of electricitypowered products mainly derives from the raw materials and fuels necessary for electricity generation, when this is not produced through renewable systems. This is the case, for example, for oil and natural gas production and processing, transportation and for operations necessary to run the power plants. These impacts are not only reflected in the Global Warming Potential (GWP) indicator, but also in several others, such as the