  We propose a Markovian model to understand how Italy's public sphere behaves
on the green energy transition theme. The paper uses the example of solar
photovoltaics as a point of reference. The adoption decision is assumed to be
sequentially influenced by the network communication of each person or family
and the payback period of the investment. We apply the model for a case study
based on the evolution of residential PV systems in Italy over the 2006-2026
period. The baseline configuration of the model is calibrated based on the
actual diffusion of residential PV in Italy from 2006 to 2020. The
comprehensive analysis leads to a discussion of two interesting societal
implications. (1) Cognitive biases such as hyperbolic discounting of individual
future utility crucially influence inter-temporal green choices. (2) Individual
green choices count for the effect that it has on the chances that other
individuals will also make a choice, in turn abating other greenhouse gas
emissions.
