Uncertainty assessment by a Monte Carlo simulation in a life cycle inventory of electricity produced by a waste incinerator

The existence of uncertainties is often mentioned as a crucial limitation for a clear interpretation of LCA results. Due to this problem, slowly the uncertainty analysis is gaining importance in the realisation of LCAs, but its use is not common practise. As an example of application for a typical process chain of many LCAs, the uncertainties in the Life Cycle Inventory (LCI) of a life cycle study on waste incineration in Tarragona/Spain has been analysed. The procedure applied consists of selection of essential parameters, determination of probability distributions, Monte Carlo simulation, significance analysis and interpretation of the results. By the use of the obtained probability distributions for the essential factors in a Monte Carlo Simulation, the inventory results were transformed from a concrete value into a probability distribution around a mean value. The probability distributions obtained correspond to a better understanding of the magnitude of the uncertainties in LCA results.