Caltech-Taiwan Energy Exchange (CTEE): 2012 to 2014
CTEE was a 3-year international energy research collaboration between Caltech and the National Central University in Taiwan. The program teamed faculty from universities in Taiwan with their counterparts at Caltech to investigate projects in six key sustainable energy technology areas: Biofuels, CO2 sequestration/porous media, fuel cells, smart grid, solar PV and thermelectrics.
Supported by the National Science and Technology Program for Energy, the collaboration provided a unique opportunity for scientists from both nations to learn from each other while developing critical technologies. The collaboration ran from January 2012 through December 2014.
View the location of CTEE's collaborating universities in Taiwan on our Collaborator's Map.
Novel Cellulases by SCHEMA Recombination
Caltech PI: Frances H. Arnold
Taiwan PIs: Yu-Chan Chao, Po-Huang Liang, Su-May Yu, and Andrew H.-J. Wang from Academia Sinica
The objective of this collaboration was to use computational and experimental tools Caltech developed for recombination and directed evolution to generate highly active, stable enzymes to be used to breakdown lignocellulosic biomass.
The Taiwanese collaborators identified several promising new endoglucanases and beta-glucosidases, which will benefit from further improvement using Caltech's methods. In addition, we will apply the same methods to several industrial 'workhorse' enzymes, for comparison.
We aim to design libraries of recombined proteins containing many active members. Careful sampling of the recombined enzymes will allow us to build a model of the relationship between stability and sequence. This model will be used to predict the most stable recombinant sequences, which we will then construct and characterize.
We will also work to implement directed evolution methods to improve these enzymes.
CO2 Sequestration / Porous Media
Simulation/Design/Synthesis of Nanocomposites for CO2 Capture and Conversion at Elevated Temperature
Caltech PI: William A. Goddard
Taiwan PIs: San-Yuan Chen, National Chiao Tung University; Pu-Wei Wu, National Chiao Tung University; Chia-Min Yang, National Tsing Hua University; Jeng-Han Wang, National Taiwan Normal University
The collaboration provided a cohesive 3-year strategy for carbon capture and storage at mid-to-high temperature and included 3 sub-projects:
II: Simulation/Design/Synthesis of H2 Permeable Membranes at Elevated Temperature
III: Simulation/Design/Synthesis of Photocatalytic Materials for CO2 Conversion.
In sub-project I, the primary focus was to carry out synthesis and structural characterization of nanoporous Ca-based LDHs, and study CO2 absorption and desorption behavior and related kinetics for mesoporous Ca-based LDH membranes in different settings (pressure, temperature, gas mixtures, cycling etc.). Theoretical simulations were performed to help in designing chemically stable compounds/membranes that display reversible uptake and release of carbon dioxide at 500~700°C.
The goal of sub-project II was to fabricate composite cermet membranes for hydrogen permeation. We built a metal-ceramics composite system and performed multi scale computational simulations on this system with H2/CO2 gas at various ratios and temperatures to study gas selectivity and hydrogen diffusion through the system. The computational results were compared with experimental ones to validate our predictive approach and models.
In sub-project III, the reaction mechanism for CO2 with H2O and H2 will be investigated. Using 2-D periodic models of TiO2, Cu and Pt, we examined how contact between the semiconductor and metal slabs affects the free metals' band energies and spatial distributions.
Development of High Performance Composite Cathode for SOFC Application
Caltech PI: Sossina M. Haile
Taiwan PI: Kuan-Zong Fung of National Cheng Kung University
Achieving high performance in solid oxide fuel cells (SOFCs) at moderate temperatures (400 – 700 °C) has been a key goal of the fuel cell community because operation at such intermediate temperatures would dramatically lower costs and enhance device lifetimes.
Amongst the three fuel cell components, the cathode in SOFCs remains the most challenging at these temperatures. In this project we aim to carefully determine electrochemical reaction pathways using the promising bismuth oxide based compounds identified by our Taiwanese counterparts, Professor Kuan-Zong Fung and colleagues at the Dept. of Materials Science and Engineering.
We aim to measure fundamental electrochemical activity using a variety of well-defined electrode structures. During year 1, we develop PLD conditions for depositing bismuth oxide based cathode materials and perform symmetric cell measurements under zero-bias of compositions identified by the Taiwanese partners. In year 2, we develop patterning techniques for candidate cathode materials and perform both symmetric (zero bias) and asymmetric (biased) electrochemical measurements to establish active sites and site dependence on bias. In year 3, we develop fabrication routes for embedded electrode geometry and deposition of nanoparticle catalysts. We also measure catalytic activity and characterize activity of selected composites under biased conditions using asymmetric geometry.
Uncertainty Mitigation for Renewable Energy Integration
Caltech PI: Steven Low
Taiwan PIs: Faa-Jeng Lin, National Central University; Ying-Yi Hong, Chung Yuan Christian University; Chao-Rong Chen, National Taipei University of Technology
This project was part of a broader program on scalable endpoint-based control to mitigate the uncertainty of renewables. The specific focus was on two problems (i) the inverter control for voltage regulation and VAR support in a distribution network with high penetration of renewable generation such as wind and solar photovoltaics; and (ii) demand response that attempts to match elastic demand to fluctuating supply.
For each of these problems, mathematical models were developed. We then derive scalable distributed control algorithms, and analyze their properties. We also conduct simulations, collect data, evaluate the performance of the algorithms in realistic settings, and use the findings to refine our models and algorithms.
The expected outcome is a set of models, distributed control algorithms for volt/VAR control and demand response, and their performance evaluation using mathematical analysis and simulations.
This collaboration examines the use of thin coatings to improve optical, electrical and mechanical performance in thin film solar cells.
Our initial focus was on the design of nanostructured amorphous oxide thin film coatings for enhanced performance in amorphous silicon and germanium cells and copper-indium-gallium-diselenide (CIGS) solar cells. Full wave electromagnetic simulations were used to design nanoscale light trapping structures for enhanced solar absorption. Nanostructured printed films of >4 cm2 were fabricated using nanoimprint lithography. Enhanced absorption was characterized using angle-dependent spectral response measurements, light I-V and efficiency measurements.
For investigation of the mechanical properties, the main focus of the proposed work was to develop and characterize the dielectric layer. Finite Element Modeling (FEM) was employed to create virtual patterns in the passivation layer with realistic stiffnesses, and inputs into the models were experimentally determined parameters generated by nanoindentation and wafer curvature techniques.
Phase Equilibria and Microstructural Studies of Thermoelectrically Important Co-Sb-Ga System
Caltech PI: G. Jeffrey Snyder
Taiwan PI: Sinn-Wen Chen of National Tsing Hua University
The project aims to provide leadership in the burgeoning field of self-assembled, composite thermoelectrics by establishing an expertise in composite skutterudites.
In this project, Caltech developed new high thermoelectric efficiency skutterudite composites capitalizing on the unique strengths and capabilities of Prof. Sinn-wen Chen's group at NTHU, Taiwan. The research objectives at Caltech are to identify high efficiency (ZT) skutterudite composites.
In year 1, ternary Co-Sb-M composites are made using precipitation reactions and directionally solidified Bridgeman samples, starting with M=Ga and proceeding to other candidates such as In, Ni, Fe, Ce. In year 2, Caltech designs thermoelectric nanocomposites using the initial phase diagram information of NTHU and uses this information to control the characteristic size and morphology of the microstructure. The addition of doping elements to control carrier concentration is included to assess the influence of microstructure on doping control. In year 3, synthesis procedures (composition, time and temperature of growth and annealing) are developed based on the phase diagrams to create microstructures of properly doped skutterudites with phonon-scattering secondary phases resulting in high thermoelectric efficiency.