tailieunhanh - Biofuels, Solar and Wind as Renewable Energy Systems_Benefits and Risks Episode 1 Part 9

Tham khảo tài liệu 'biofuels, solar and wind as renewable energy systems_benefits and risks episode 1 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 186 M. Giampietro K. Mayumi sector needed to deliver the required energy carriers - the energy consumption or metabolism of the energy sector and ii Net Energy to Society - used for the production and consumption of non-energy goods and services - the energy consumption or metabolism of the rest of the society. In spite of an unavoidable level of arbitrariness in the calculation of EROI this scheme indicates clearly the tremendous advantage of fossil energy over alternative energy sources for more see Giampietro 2007a . In relation to the costs of production of energy carriers oil has not to be produced it is already there. Moreover in the previous century it was pretty easy to get the EROI of oil used to be 100 MJ per MJ invested according to the calculations of Cleveland et al. 1984 . For this reason in the community of energy analysts there is an absolute consensus about the fact that the major discontinuity associated with the industrial revolution in all major trends of human development population energy consumption per capita technological progress experienced in the XXth century was generated by the extreme high quality of fossil energy as primary energy source for an overview of this point see Giampietro 2007a . This means that to avoid another major discontinuity in existing trends of economic growth this time in the wrong direction it is crucial that when looking for future alternative primary energy sources to replace fossil energy humans should obtain the same performance in terms of useful work delivered to the economy per unit of primary energy consumed. As explained earlier a very high EROI means that the conversion of oil into an adequate supply of energy carriers . gasoline and their distribution absorbs only a negligible fraction of the total energy consumption of a society. This small overhead makes it possible that a large fraction of the total energy consumptions goes to cover the needs of society with very little of it absorbed by the .