According to the 2012 World Energy Outlook, electricity demand is projected to increase worldwide by 70% in the next two decades. Meeting this demand in an environmentally sustainable way will require cost-effective and efficient technologies that support a transition from fossil fuels to renewable energy sources.
Whether by capturing the sun’s energy to produce electricity or by using fuel cells to directly convert the chemical energy in fuels to electricity, advancing these technologies requires a fundamental understanding of how materials behave at the nano-scale, and how those properties translate into macroscopic devices. At Caltech we focus on both and are making significant strides in photovoltaics, fuel cells, and distributed wind energy.
Resnick Sustainability Institute director Harry Atwater is renowned for his work in PV. In his lab, researchers are developing new solar cell architectures and light management approaches, as well as new semiconductor materials, all aimed at scaling PV to terawatt capabilities. They have developed cells made of silicon microwires embedded in a flexible polymer that require 98% less silicon than conventional ones—and developed thin, ultra high-efficiency gallium arsenide cells that have set records for efficiency. The group is also developing full spectrum solar cells that can capture more of the sun’s energy, which may yield conversion efficiencies of over 50%.
Professor Sossina Haile‘s research focuses on understanding mechanisms of ion transport and pathways for solid state electrochemical reactions. This understanding is applied to the development of advanced energy technologies and in particular fuel cells. Haile has established a new class of fuel cells based on solid acid electrolytes and has demonstrated record power densities for solid oxide fuel cells.
Former Resnick Fellow and Haile Group member Rob Usiskin studied catalysis in solid oxide fuel cells. He designed and constructed an electrochemical microprobe for ultra-fast data characterization. The device allows the user to rapidly scan many catalysts and characterize each under well-defined conditions of temperature and gas atmosphere. Rob’s work has set the stage for the Haile group to mine the resulting data for ideal catalysts.
Resnick Fellow Davide Lionetti, working with the Agapie Group, is studying O2 reduction by metal clusters relevant to fuel cell catalysis. This work has great potential for providing fundamental information on how Photosystem II functions and towards the development of a synthetic oxygen-evolving catalyst for water splitting.
Distributed Wind Energy Systems
Caltech science is pioneering the development of distributed wind energy systems thanks to bioinspired arrangements yielding optimal energy production. Professor John Dabiri’s work in wind farm design using vertical-axis turbines has resulted in his experimental farm producing 10x more power per unit area than similarly scaled conventional arrays. Precision materials as researched in the labs of Professors Robert Grubbs and Julia Greer are also improving the technology, as they have made lighter and stronger turbines possible.
This research has led to the formation of an international center of excellence for the development and dissemination of distributed wind energy science and technology. The center’s approach focuses on large arrays of smaller turbines, such that generation in wind-rich regions can be brought closer to the consumer population. The center’s scientific goals are organized around: fine-scale wind energy resource quantification; wind turbine design for manufacturability and maintenance; and wind turbine array optimization.