Abstract

The potential to save trillions of BTU’s in energy usage and billions of dollars in cost on an annual basis based on use of higher strength steel in major oil and gas transmission pipeline construction is a compelling opportunity recognized by both the US Department of Energy (DOE). The use of high-strength steels (X100) is expected to result in energy savings across the spectrum, from manufacturing the pipe to transportation and fabrication, including welding of line pipe. Elementary examples of energy savings include more the 25 trillion BTUs saved annually based on lower energy costs to produce the thinner-walled high-strength steel pipe, with the potential for the US part of the Alaskan pipeline alone saving more than 7 trillion BTU in production and much more in transportation and assembling. Annual production, maintenance and installation of just US domestic transmission pipeline is likely to save 5 to 10 times this amount based on current planned and anticipated expansions of oil and gas lines in North America. Among the most important conclusions from these studies were: • While computational weld models to predict residual stress and distortions are well-established and accurate, related microstructure models need improvement. • Fracture Initiation Transition Temperature (FITT) Master Curve properly more » predicts surface-cracked pipe brittle-to-ductile initiation temperature. It has value in developing Codes and Standards to better correlate full-scale behavior from either CTOD or Charpy test results with the proper temperature shifts from the FITT master curve method. • For stress-based flaw evaluation criteria, the new circumferentially cracked pipe limit-load solution in the 2007 API 1104 Appendix A approach is overly conservative by a factor of 4/?, which has additional implications. . • For strain-based design of girth weld defects, the hoop stress effect is the most significant parameter impacting CTOD-driving force and can increase the crack-driving force by a factor of 2 depending on strain-hardening, pressure level as a % of SMYS, and flaw size. • From years of experience in circumferential fracture analyses and experimentation, there has not been sufficient integration of work performed for other industries into analogous problems facing the oil and gas pipeline markets. Some very basic concepts and problems solved previously in these fields could have circumvented inconsistencies seen in the stress-based and strain-based analysis efforts. For example, in nuclear utility piping work, more detailed elastic-plastic fracture analyses were always validated in their ability to predict loads and displacements (stresses and strains). The eventual implementation of these methodologies will result in acceleration of the industry adoption of higher-strength line-pipe steels. « le Document type: Report

Abstract

For any proposal on energy transition, it is necessary to know the energy reality (sources, transformations, uses, impacts), so it is necessary to have suitable tools for its measurement and accounting.

The method of energy measurement and accounting most used today to assess energy needs on a large scale (regional, national and global) is a top-down approach based on the use of aggregate values of primary energies (coal, oil and derivatives, natural gas, nuclear, hydroelectric, biomass/waste, other renewable sources) with their energy value normalized to that of oil. These, once transformed, give rise to the final energy (or energy vectors: electricity, heat and commercial fuels). The balance sheets are usually completed with a breakdown of the economic sectors to which the energy flows are addressed (agriculture/forestry, fishing, industry, commercial and public services, transport, residential, non-specified and non-energy uses). Absent is the analysis of the transformations of energy in user processes to useful energy, which actually provides the effects and activates the processes (heat, light, movement, conformation of matter, information, communication, etc.).

This methodology was developed during the second half of the XX century, and especially from the creation of the main Western energy agencies, such as the Energy Information Administration (EIA) of the United States, or the International Agency for Energy (IEA) of the OECD during the 70s, and agrees with the reality of the time, based on the extraction, trade and use of fossil fuels. Its use is universal among energy agencies, think tanks, and governments around the world and is one of the main tools for determining energy policies.

This approach to energy accounting has been useful while the energy reality was fundamentally based on fossil stocks of high energy density, but it has been unable to incorporate renewable energies satisfactorily due to their dispersed and distributed nature of flows, temporarily variable, but permanent and inexhaustible.

The purpose of this communication is to highlight the shortcomings of the current model and to propose a new energy accounting that reverses the path to be taken: starting from the needs of useful energy (at user level) and taking the reverse path upstream in the search for the most efficient energy sources and itineraries. By focusing attention on the uses of useful energy, this accounting recovers some of the lost complexity and has the virtue of generating very important pedagogical effects on users, planners and society as a whole in terms of needs and the uses of energy.