5 results
Contributors
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- By Peter Bernholz, Wolfgang Ernst, Yang Fenggang, Berndt Hamm, Burkhard Hess, John F. Hoffmeyer, Tonio Hölscher, Ulrich Hübner, Edmondo F. Lupieri, Piet Naudé, Konrad Schmid, Andreas Schüle, Choon-Leong Seow, Gao Shining, Günter Thomas, Hans-Ulrich Vogel, Jürgen von Hagen, Rudolf G. Wagner, Michael Welker
- Edited by Jürgen von Hagen, Michael Welker, Universität Heidelberg
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- Book:
- Money as God?
- Published online:
- 05 June 2014
- Print publication:
- 01 May 2014, pp x-xi
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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.
Chapter 3 - Direct Solar Energy
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- By Dan Arvizu, Palani Balaya, Luisa F. Cabeza, K.G. Terry Hollands, Arnulf Jäger-Waldau, Michio Kondo, Charles Konseibo, Valentin Meleshko, Wesley Stein, Yutaka Tamaura, Honghua Xu, Roberto Zilles, Armin Aberle, Andreas Athienitis, Shannon Cowlin, Don Gwinner, Garvin Heath, Thomas Huld, Ted James, Lawrence Kazmerski, Margaret Mann, Koji Matsubara, Anton Meier, Arun Mujumdar, Takashi Oozeki, Oumar Sanogo, Matheos Santamouris, Michael Sterner, Paul Weyers, Eduardo Calvo, Jürgen Schmid
- Edited by Ottmar Edenhofer, Ramón Pichs-Madruga, Youba Sokona, Kristin Seyboth, Susanne Kadner, Timm Zwickel, Patrick Eickemeier, Gerrit Hansen, Steffen Schlömer, Christoph von Stechow, Patrick Matschoss
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- Book:
- Renewable Energy Sources and Climate Change Mitigation
- Published online:
- 05 December 2011
- Print publication:
- 21 November 2011, pp 333-400
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Summary
Executive Summary
Solar energy is abundant and offers significant potential for near-term (2020) and long-term (2050) climate change mitigation. There are a wide variety of solar technologies of varying maturities that can, in most regions of the world, contribute to a suite of energy services. Even though solar energy generation still only represents a small fraction of total energy consumption, markets for solar technologies are growing rapidly. Much of the desirability of solar technology is its inherently smaller environmental burden and the opportunity it offers for positive social impacts. The cost of solar technologies has been reduced significantly over the past 30 years and technical advances and supportive public policies continue to offer the potential for additional cost reductions. Potential deployment scenarios range widely—from a marginal role of direct solar energy in 2050 to one of the major sources of energy supply. The actual deployment achieved will depend on the degree of continued innovation, cost reductions and supportive public policies.
Solar energy is the most abundant of all energy resources. Indeed, the rate at which solar energy is intercepted by the Earth is about 10,000 times greater than the rate at which humankind consumes energy. Although not all countries are equally endowed with solar energy, a significant contribution to the energy mix from direct solar energy is possible for almost every country. Currently, there is no evidence indicating a substantial impact of climate change on regional solar resources.
Stereoselectivity of Pseudomonas cepacia lipase toward secondary alcohols: A quantitative model
- TANJA SCHULZ, JÜRGEN PLEISS, ROLF D. SCHMID
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- Journal:
- Protein Science / Volume 9 / Issue 6 / June 2000
- Published online by Cambridge University Press:
- 01 June 2000, pp. 1053-1062
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- June 2000
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The lipase from Pseudomonas cepacia represents a widely applied catalyst for highly enantioselective resolution of chiral secondary alcohols. While its stereopreference is determined predominantly by the substrate structure, stereoselectivity depends on atomic details of interactions between substrate and lipase. Thirty secondary alcohols with published E values using P. cepacia lipase in hydrolysis or esterification reactions were selected, and models of their octanoic acid esters were docked to the open conformation of P. cepacia lipase. The two enantiomers of 27 substrates bound preferentially in either of two binding modes: the fast-reacting enantiomer in a productive mode and the slow-reacting enantiomer in a nonproductive mode. Nonproductive mode of fast-reacting enantiomers was prohibited by repulsive interactions. For the slow-reacting enantiomers in the productive binding mode, the substrate pushes the active site histidine away from its proper orientation, and the distance d(HNε − Oalc) between the histidine side chain and the alcohol oxygen increases. d(HNε − Oalc) was correlated to experimentally observed enantioselectivity: in substrates for which P. cepacia lipase has high enantioselectivity (E > 100), d(HNε − Oalc) is >2.2 Å for slow-reacting enantiomers, thus preventing efficient catalysis of this enantiomer. In substrates of low enantioselectivity (E < 20), the distance d(HNε − Oalc) is less than 2.0 Å, and slow- and fast-reacting enantiomers are catalyzed at similar rates. For substrates of medium enantioselectivity (20 < E < 100), d(HNε − Oalc) is around 2.1 Å. This simple model can be applied to predict enantioselectivity of P. cepacia lipase toward a broad range of secondary alcohols.
Stereoselectivity of Mucorales lipases toward triradylglycerols—A simple solution to a complex problem
- HOLGER SCHEIB, JÜRGEN PLEISS, ANDREA KOVAC, FRITZ PALTAUF, ROLF D. SCHMID
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- Journal:
- Protein Science / Volume 8 / Issue 1 / January 1999
- Published online by Cambridge University Press:
- 01 January 1999, pp. 215-221
- Print publication:
- January 1999
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The lipases from Rhizopus and Rhizomucor are members of the family of Mucorales lipases. Although they display high sequence homology, their stereoselectivity toward triradylglycerols (sn-2 substituted triacylglycerols) varies. Four different triradylglycerols were investigated, which were classified into two groups: flexible substrates with rotatable O′-C1′ ether or ester bonds adjacent to C2 of glycerol and rigid substrates with a rigid N′-C1′ amide bond or a phenyl ring in sn-2. Although Rhizopus lipase shows opposite stereopreference for flexible and rigid substrates (hydrolysis in sn-1 and sn-3, respectively), Rhizomucor lipase hydrolyzes both groups of triradylglycerols preferably in sn-1. To explain these experimental observations, computer-aided molecular modeling was applied to study the molecular basis of stereoselectivity. A generalized model for both lipases of the Mucorales family highlights the residues mediating stereoselectivity: (1) L258, the C-terminal neighbor of the catalytic histidine, and (2) G266, which is located in a loop contacting the glycerol backbone of a bound substrate. Interactions with triradylglycerol substrates are dominated by van der Waals contacts. Stereoselectivity can be predicted by analyzing the value of a single substrate torsion angle that discriminates between sn-1 and sn-3 stereopreference for all substrates and lipases investigated here. This simple model can be easily applied in enzyme and substrate engineering to predict Mucorales lipase variants and synthetic substrates with desired stereoselectivity.