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Chapter 11 - Renewable Energy
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- By Wim Turkenburg, Utrecht University, Doug J. Arent, National Renewable Energy laboratory, Ruggero Bertani, Enel Green Power S.p.A., Andre Faaij, Utrecht University, Maureen Hand, National Renewable Energy Laboratory, Wolfram Krewitt, German Air and Space Agency, Eric D. Larson, Princeton University and Climate Central, John Lund, Geo-Heat Center, Oregon Institute of Technology, Mark Mehos, National Renewable Energy Laboratory, Tim Merrigan, National Renewable Energy Laboratory, Catherine Mitchell, University of Exeter, José Roberto Moreira, Biomass Users Network, Wim Sinke, Energy Research Centre of the Netherlands, Virginia Sonntag-O'Brien, REN21, Bob Thresher, National Renewable Energy Laboratory, Wilfried van Sark, Utrecht University, Eric Usher, United Nations Environment Programme, Dan Bilello, National Renewable Energy Laboratory, Helena Chum, National Renewable Energy Laboratory, Diana Kraft, REN21, Philippe Lempp, German Development Ministry, Jeff Logan, National Renewable Energy Laboratory, Lau Saili, International Hydropower Association, Niels B. Schulz, International Institute for Applied systems Analysis, Austria and Imperial College, Aaron Smith, National Renewable Energy Laboratory, Richard Taylor, International Hydropower Association, Craig Turchi, National Renewable Energy Laboratory, Jürgen Schmid, Fraunhofer Institute for Wind Energy and Energy System Technology
- Global Energy Assessment Writing Team
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- Book:
- Global Energy Assessment
- Published online:
- 05 September 2012
- Print publication:
- 27 August 2012, pp 761-900
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Summary
Executive Summary
Renewable energy sources – including biomass, geothermal, ocean, solar, and wind energy, as well as hydropower – have a huge potential to provide energy services for the world. The renewable energy resource base is sufficient to meet several times the present world energy demand and potentially even 10 to 100 times this demand. This chapter includes an in-depth examination of technologies to convert these renewable energy sources to energy carriers that can be used to fulfill our energy needs, including their installed capacity, the amount of energy carriers they produced in 2009, the current state of market and technology development, their economic and financial feasibility in 2009 and in the near future, as well as major issues they may face relative to their sustainability or implementation.
Present uses of renewable energy
Since 1990 the energy provided from renewable sources worldwide has risen at an average rate of nearly 2% a year, but in recent years this rate has increased to about 5% annually (see Figure 11.1.) As a result, the global contribution of renewables has increased from about 74 EJ in 2005 to about 89 EJ in 2009 and represents now 17% of global primary energy supply (528 EJ, see Figure 11.2). Most of this renewable energy comes from the traditional use of biomass (about 39 EJ) and larger-scale hydropower (about 30 EJ), while other renewable technologies provided about 20 EJ.
Structural and electrical properties of single Ga/ZnO nanofibers synthesized by electrospinning
- Yuval Shmueli, Gennady E. Shter, Ossama Assad, Hossam Haick, Philippe Sonntag, Philippe Ricoux, Gideon S. Grader
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- Journal:
- Journal of Materials Research / Volume 27 / Issue 13 / 14 July 2012
- Published online by Cambridge University Press:
- 17 May 2012, pp. 1672-1679
- Print publication:
- 14 July 2012
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Nanofibers (NFs) of Ga-doped ZnO (GZO) were prepared by electrospinning of polymer–salts solution. Sintering profiles reported in the literature led to loss of the fibrous structure. Hence, the morphology, thermal stability, and phase composition of green and sintered fibers were investigated as function of sintering conditions to elucidate this degradation process. Optimal results were obtained at 400 °C for 30 min. This low temperature sintering of GZO fibers has not been previously reported. The fibers were porous with a significant surface area, making it possible to test their sensitivity to environmental changes. In particular, the response of the GZO NFs to changes in humidity was demonstrated for the first time. The electrical and sensing properties of single NFs prepared at these conditions were studied using a field-effect transistor mode.