Nanotechnology holds promise for necessary breakthroughs in a number of critical energy sectors, including solar cells, thermoelectric conversion and transport, hydrogen storage, and electrochemical conversion and storage (i.e., batteries, capacitors and fuel cells), according to scientists participating in the first Energy Nanotechnology International Conference (ENIC2006) held June 26-28 at MIT.
The technical conference included invited and contributed presentations from academia and industry. Among the speakers were Michael Graetzel, professor at the École Polytechnique Fédérale de Lausanne in Switzerland, and MIT Institute Professor Mildred Dresselhaus.
Solar. Researchers described a number of approaches to developing solar photon conversion systems that have an appropriate combination of high efficiency and low capital cost.
MIT’s Vladimir Bulovic, for one, said that nanotechnologies such as nanodots and nanorods are potentially disruptive technologies in the solar field. Bulovic is fabricating quantum dot photovoltaics using a microcontact printing process.
I think we’ll see the peaking of oil and natural gas sooner than most of those in the fossil fuel industry think. By 2035 photovoltaics could produce about 10 percent of the world’s electricity and play a major role in reducing carbon dioxide emissions.—David Carlson, chief scientist at BP Solar
Thermoelectrics. Thermoelectric devices are able to increase the efficiency of current technology and processes by transforming typical waste heat in combustion processes into electrical energy without the production of any environmentally harmful by-products.
There is a strong incentive to develop novel thermoelectric materials for power generation with a vastly improved thermoelectric performance. Nanomaterials have a role to play in meeting this challenge because of expectations for enhanced power factor and greatly reduced thermal conductivity in suitably chosen systems. Therefore general, convenient synthetic routes to bulk nanostructured materials, designed to be thermodynamically stable and thus practically permanent, are needed.—Mercouri G. Kanatzidis, Michigan State University
Hydrogen. Mildred Dresselhaus gave a plenary talk titled “Addressing Grand Energy Challenges Through Advanced Materials” in which she focused on the large gap between present science/technology knowhow and the requirements in efficiency/cost for a sustainable hydrogen economy.
The hydrogen initiative involves an effort to greatly increase our capability to produce hydrogen using renewable energy sources such as photons from the sun and water from the oceans, since hydrogen is an energy carrier and not a fuel found on our planet.
The hydrogen storage problem has been identified as the most challenging since neither liquid hydrogen nor solid hydrogen have enough energy density to meet the DOE requirements for hydrogen storage for automotive applications.
The third element of the hydrogen initiative involves the development of fuel cells with a much enhanced performance and lower cost, that would come about through the development of more effective catalysts in the anode and cathode of the fuel cell and more efficient membranes operating at elevated temperatures allowing proton flow but inhibiting hydrogen gas flow.
For each of the three components of the hydrogen initiative, hydrogen production, storage and utilization, it appears that the special properties of materials at the nanoscale can be utilized to enhance performance in a way that cannot be done with bulk materials.—Mildred Dresselhaus, MIT
Energy storage. Speakers in this track focused on fuel cells, batteries and supercapacitors.
Many significant efforts are being made to identify and utilize new energy sources, to increase production of existing sources, to increase conversion and storage efficiency, and, equally important, to reduce pollution. However, incremental improvement will not be sufficient. What is needed are new approaches.
At the same time, we are entering an exciting era where we now have the technology to engineer materials on a nanometer scale, i.e. at dimensions comparable to the size of individual atoms and molecules. But what does nanotechnology have to do with the world’s massive energy needs? In my keynote address, I will explore nanotechnology as an “outside the box” technology that has the potential to “re-invent” (transform) some long-known but little-used technologies to the point that they may offer significant improvement over the accepted ways of converting and storing energy.
One such transformation would be to use capacitors rather than batteries for regenerative energy storage. Ridiculous? Perhaps not. In MIT’s Laboratory for Electromagnetic and Electronic Systems (LEES), we are exploring a nanostructured ultracapacitor electrode that has the potential to increase a capacitor’s energy storage density to equal that of a chemical battery.
Another technology that we are exploring is the use of nanostructured emissive coatings and filters to significantly increase the efficiency of direct thermophotovoltaic (TPV) generation of electricity from heat.—Joel Schindall, MIT
There is widespread effort and excitement in new materials for storing and releasing lithium or hydrogen. New materials are needed if rechargeable batteries and fuel cell systems are to be more competitive in the transportation sector, for example.—Brent Fultz, California Institute of Technology
The conference was organized by the American Society of Mechanical Engineers (ASME) Nanotechnology Institute. Manuscripts submitted to the conference will be published in a future issue of the ASME Journal of Heat Transfer.