Global impact of friction on energy consumption, economy and environment

Energy is a key resource for our society today and will be crucial for our sustainability in the future. A considerable amount of energy is consumed to overcome friction, especially in the transportation, industrial, and power-generation sectors, and major economic losses are also due to wear of products and components and their replacement. Jost [1] concluded that studies carried out in several industrial countries indicate that 1.0 to 1.4 % of the gross national product can be saved by introducing better tribological practices, requiring investment in research and development at a rate of one in 50 of the savings obtainable. Today, considerable effort is being devoted to producing increasingly more energy efficient vehicles and machines, not only for economic reasons, but also to help meet the requirements for reduced CO2 emissions arising from the Kyoto Protocol on climate change. A major source of CO2 emissions are cars and trucks. Transportation consumes about 20 % of the global primary energy and accounts for about 18 % of the total anthropogenic greenhouse gas emissions [2,3]. In this paper we summarize our studies for calculating the global energy consumption due to friction and potential savings from friction reduction in transportation and in industry [4-6]. We first focused our attention on passenger cars for two reasons: passenger cars form a major consumer of energy and also generate a considerable part of the greenhouse gas emissions. The other reason was that the energy use in passenger cars has been largely studied on the systemto-component level. The present study is based on the current set of technical solutions for passenger cars, trucks, buses and advanced industrial processing machinery here represented by paper machines, while the effects of expected changes, future trends, and predictions in this set are not included.