Defence of dissertation in the field of Network Technology, M.Sc. (Tech.) Matti Pärssinen

There are two ways to reduce ICT energy consumption. The first one is to improve the energy efficiency of the devices and the second one is to make ICT services consume less resources and energy. This dissertation assesses the energy consumption of the ICT infrastructure and gives case examples of both options of consumption reduction. The first case examines the reusing of waste heat emerging from data centers (DCs), and the second case focuses on reducing ad fraud traffic in online advertising.

The developed framework with 2016 values reveals that ICT infrastructure consumed 1058 TWh of energy (with uncertainty from 839 to 1278 TWh). The results show that data centers can become more energy efficient and sustainable by investing in waste heat reuse and it is economically profitable. The carbon emissions of online advertising are a growing concern. The share of ad fraud traffic was is close to one-fourth of the total online ad traffic. The dissertation discussed the use of blockchains to control fraudulent advertising traffic and therefore reducing resource consumption and concludes that blockchain can become a solution to address some of the issues of ad fraud, but the current technology is not ready. The results can be used to justify the investments required to improve the sustainability of ICT.

According to the IPCC report in 2018, the current rate of consumption causes global warming of 1.5 °C between 2030 and 2052. Despite the positive impacts of dematerialization, decarbonization, and demobilization, there is a growing concern on the environmental impact of ICT. Demystification of the environmental impact of ICT is required to increase understanding of decision makers.