Our research focuses on CO2 emissions along supply chains, from freight energy use to inventories storage. These supply chains are Collaborative Networked Organisations (CNOs) linking together actors operating along the same value stream. A supply chain model using a discrete event simulation was developed. Our CNO model is able to simulate a three tier supply chain. Four tuneable variables are provided: manufacturing capability, locations, mode of transportation and types of products. The product data are from Carrier, a large manufacturer and distributor of heating, ventilating and air conditioning systems. Their purpose is to compare levels of CO2 emitted for differing configurations of different scenarios. Some results are logical, but others are unexpected. The principal objectives of this study are twofold: providing a realistic decision support for simulating and promoting sustainable collaborative networks (CNs), helping managers to select eco-friendly supply chains.