Towards Sustainable Data Centers and ICT Services

Research output: ThesisDoctoral ThesisCollection of Articles


According to the Intergovernmental Panel on Climate Change report in 2018, the current rate 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. Can services moving online be considered sustainable development? Favorable and adverse environmental impacts can be found on all system levels. There is a possible rebound effect; even though the energy efficiency of devices has improved, the scale of use has increased at a rate which results in an increase in the total energy consumption.  There are two ways to reduce ICT energy consumption: 1) improve the energy efficiency of the devices and 2) make ICT services consume less resources and energy. This thesis assesses the energy consumption of the ICT infrastructure and gives case examples of both options of consumption reduction. The first case examines reusing of waste heat emerging from data centers (DCs), and the second case focuses on reducing ad fraud traffic in online advertising.  The energy efficiency of DCs is becoming more critical as their number is growing. The electricity consumed by a DC converts to heat. However, most of the heat is not utilized, even though different solutions already exist. Online advertising is associated with funding online search services, map services, and social media to billions of users, and the sustainable growth of this industry is seen as necessary. Online ads are almost indistinguishable to end-users, but consume a significant part of the resources. Online ads increase energy consumption through four factors: 1) the amount of downloaded data increases, 2) the varying inter-transfer interval reserves resources, 3) the time required to access the payload content or application increases, and 4) the amount of active connections increases.  The results of this thesis show that DCs can become more energy efficient by investing in waste heat reuse. The investment is profitable inside the full range of uncertainty in large DCs. In medium DCs, the extremely pessimistic factor values result in a negative outcome. Small DCs are sensitive to factor variations. In 2016, online advertising consumed 20–282 TWh of energy. With 2016 input factor values, online advertising consumed 106 TWh of energy. The carbon emissions were 60 Mt CO2e (between 12 and 159 Mt of CO2e with uncertainty). The share of ad fraud traffic was 13.87 Mt of CO2e emissions (between 2.65 and 36.78 Mt of CO2e with uncertainty). The thesis discussed the use of blockchains to control fraudulent advertising traffic, and concludes that blockchain can become a solution to address some of the issues of ad fraud, but the current technology is not ready.
Translated title of the contributionKohti kestäviä datakeskuksia ja ICT palveluita
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
  • Manner, Jukka, Supervising Professor
  • Haimi, Suvi, Thesis Advisor, External person
Print ISBNs978-952-60-8611-8
Electronic ISBNs978-952-60-8612-5
Publication statusPublished - 2019
MoE publication typeG5 Doctoral dissertation (article)


  • sustainability
  • internet services
  • energy efficiency
  • environmental impact assessment
  • data center
  • online advertising
  • ad fraud
  • blockchain


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