Purpose

The purpose of this article is to realize a review of studies dealing with life cycle assessment of electric grids or their components, in order to put in evidence methodological aspects to be considered with particular attention or requiring further deepening in future researches. After a preliminary bibliographic screening, the review analyses 16 scientific articles.

Methods

The review considers 16 studies which are all based on a life cycle perspective and pays particular attention on

some methodological issues such as: functional unit definition, selection of the impact categories, energy mix taken into

consideration in order to quantify the environmental impact associated with grid losses, and end of life of grid components. The review considers, also, the analysed studies’ compliance to ISO 14040 recommendations.

Results and discussion

 All the 16 studies have a good degree of compliance with ISO 14040. Concerning impact categories selection, the review showed a wide set of impacts taken into consideration: some categories are frequently utilized while

others are present only in few studies. The analysis puts in evidence that recycling is a crucial aspect, determining a sensible reduction of impacts, which in some cases can compensate for the total impact of the end-of-life stage. Energy losses have a great influence on the overall impact. Neglecting losses in the valuation of networks or resistive components may be too simplifying, if not even misleading. Selecting a suitable functional unit is not an easy task.

Conclusions

Beyond the specific outcomes, the analysis puts in evidence two general research needs. First, the definition of functional unit: some authors use a very specific functional unit which allows a correct description of the service provided by an electricity network while others use a functional unit allowing easier comparison with other studies. Second, considering the loss relevance and the infrastructure lifespan, an appropriate evaluation of the electricity mix is crucial.