Catching up
with the plant
kingdom
Research and
development pursues
and exploits solar
energy in many ways.

HASSAUN JONES-BEY, SENIOR EDITOR

 

current 10% to 15% for the best silicon-based technology. More manufacturable and cost-effective photovoltaic technologies, including polymer, photochemical, and even quantum-dot solar cells, have reached conversion efficiencies near 11% (see www.laserfocus- world.com/articles/252486). But even

When one considers that a very large and nearby nuclear-powered, blackbody photon radiator, commonly known as “the Sun” either directly or indirectly powers every process on Earth— including “renewable” wind and geothermal energies, as well as the production of fossil fuels that are being consumed faster than they can be renewed—the question becomes: Energy crisis? What energy crisis? Humankind is constantly bathed in orders of magnitude more energy than we could possibly use. In fact, the worldwide energy crisis seems to have a lot less to do with shortages than with learning to negotiate our abundantly life-sustaining sea of photonic energy in ways that can be less toxic to our own continued existence.

The plant kingdom appears to be ahead of humanity in this regard. Two-dimensional femtosecond IR spectroscopy studies of the photosynthesis process at Lawrence Berkeley National Laboratory (Berkeley, CA) indicate that Mother Nature has developed a far more efficient method for harvesting light in photosynthesis than humans have in solar cells (see www.laserfocusworld.com/ articles/231742). But humanity is taking steps to close the gap.

In addition to solar-cell technology, which converts sunlight directly to electricity using the photovoltaic effect, R&D at the U.S. Department of Energy (DOE) National Renewable Energy Laboratory (Golden, CO) in collaboration with academia and industry

includes concentrating-solar-power technologies that generate electricity indirectly. These technologies include mirrors to concentrate solar radiation and heat a fluid that can then drive an electrical generator; passive solar heating and lighting of buildings; active and passive solar water heating; and solar ventilation, process heating, and air conditioning for industrial and commercial buildings (see Fig. 1). ¹

In July, the National Institute of Standards and Technology (NIST; Gaithersburg, MD) began a 15-month research project at its new Roof Photovoltaic Test Facility to monitor the electrical and thermal performance of seven different photovoltaic (PV) roofing products that are designed to be integral parts of the roof and provide electricity and shelter from the elements. The NIST project is examining residential systems designed for sloped roofs and commercial building units designed for flat industrial roofs. Ultimately, the project is intended to provide PV users with a new generation of simulation models developed or validated with NIST data that will be useful in any given geographic location, building orientation, and with any pho-tovoltaic-cell technology. ²

A good bit further away from practical use (with the notable exception of providing electrical power for spacecraft), photonic energy—both PV and thermal PV—continues to be explored for transportation applications. A high school team named Sundancer from the Houston Vocational Center ( Houston, MS) claimed its sixth consecutive win at the Dell-Winston Solar Car Challenge this summer. The challenge is an annual solar race for high schools hosted by The Winston School in Dallas, TX. The Sundancer team, powered by an array of Schott solar cells, completed 392 laps around the Texas Motor Speedway at an average speed of