Carbon Footprint vs Energy Optimization in IoT Network Deployments

We are witnessing the full integration of the Internet of Things (IoT) into many social and economic sectors. Part of this unprecedented growth is due to the emergence of new communication technologies such as Low Power Wide Area Networks (LPWAN), which have been the catalyst for previously unfeasible smart applications. Efforts to optimize energy consumption in these types of networks have been necessary to extend their lifetime. However, not much attention has been paid to the study and optimization of the carbon footprints (CF) of these network deployments. In general, it has always been understood that minimizing energy consumption should also minimize the carbon footprint. In this work, the carbon footprint of a generic IoT network that uses renewable energy sources and communicates via LoRa is explored, and an optimization framework is proposed. We have found that minimizing energy consumption and the carbon footprint are two different things. In fact, we show that it is not possible to minimize the carbon footprint without greater energy consumption, and vice versa. This is due to the placement of gateways in the network. Our findings could be extrapolated to other networks with similar topologies. These results suggest that a fresh perspective on the optimization of IoT networks is needed to seriously consider environmental sustainability criteria that has been ignored up to now.