Energy and Environmental Applications
Ever increasing needs for energy coupled with concerns about greenhouse gas emissions have emphasized the need for alternative energy sources as well as the need to increase the energy efficiency of systems we use today.
One notable effort has been the replacement of incandescent light bulbs (once used widely in homes and offices) with more efficient lighting sources. Incandescent bulbs, originally commercialized in the late 19th century, are being replaced by devices that provide more visible light for the same level of electrical energy input. The European Union is in the process of phasing out incandescent light bulbs in favor of more energy-efficient lighting. If every filament-based light bulb in the USA were replaced by a solid state lighting source, the electricity consumption in the US would be reduced by 10%, also cutting carbon emissions by about 28 million tons a year.
The alternative light sources have included fluorescent lamps and high-intensity discharge lamps, but light-emitting diodes (LEDs) have rapidly developed into the replacement of choice for many applications. Nanotechnology innovations have led the way in reducing the cost of producing some of the alternative light bulb designs especially those that use LEDs.
Nanomaterials are beginning to play a prominent role in developing other alternative energy technologies. Much of the solar cells produced worldwide today rely on bulk crystalline technology which competes with the computer chip industry for silicon – the principal raw material used for making integrated circuits and solar cells. This is not a desirable situation since both solar energy and computer electronics are critical technologies with high demand and expanding volumes. Alternative research directions include novel nanomaterials such as quantum dots to increase solar cell efficiency and production of solar cells on flexible substrates (including polymer films and thin metal sheets). Lightweight and high strength composites for wind turbine blades are being developed using nanocomposites to harness wind energy.
Environmental pollution of air, soil and water, including the impact of toxic waste in landfills, is a major concern across the world. Using nanotechnology, scientists are designing new catalysts for waste remediation and for conversion of toxic gases into benign species. These designs take advantage of the large surface area of nanomaterials and of the novel properties and reactivity that arise at the nanoscale. New, efficient filters to trap mercury, heavy metals and other hazardous substances are being developed using carbon nanotubes and other nanomaterials.
