Renewable energy penetration in food delivery: Coupling photovoltaics with transport refrigerated units

Numbers of refrigerated transports are recording an impressive growth due to increased demand of chilled and frozen food. They require fuel consumption for traction, but also for feeding the diesel-driven refrigeration unit, which maintains the desired internal vehicle temperature. A photovoltaic integrated delivery process is investigated, in order to foster renewable energy penetration into the cold chain, thus improving its sustainability. It involves photovoltaic panels installed on the rooftop of semitrailers, a battery bank and a power conversion system to cover refrigeration requirements, removing the diesel engine from the refrigeration unit. A minimum cost multi-period Constraint Programming model is proposed to size the system, by matching refrigeration requirements with photovoltaic generation potential along the journey, both variable with daily and seasonal climate conditions. Application to a reference case of palletised frozen food distribution in North-Eastern Italy shows how drastic greenhouse gas emission reduction can be achieved per vehicle, with payback period expected to decrease below 2 years in the next decade. Sensitivity analysis on internal temperature for chilled food and different climate conditions, as well as the worst case analysis, are performed, confirming the capability of the model to act as a decision support tool for greening the cold chain.