This Friday, the first manned, solar-powered aircraft to attempt crossing the Atlantic and subsequently circling the globe will leave its top-secret concealment inside a Zurich hangar for the world to view. The Solar Impulse will have the wingspan of an Airbus yet weigh no more than an average car. It will run on an engine normally fit to power a scooter and demand no more electricity than needed to light a shop window. Almost 12,000 solar cells cover the top of its 262-foot wing. The visionary behind global solar flight, Bertrand Piccard, comes from a long line of adventurers. His ... Read More
Keeping Cool With the Albedo Effect
April 2, 2009 • By • 3 Comments
Govindasamy Bala and his colleagues at Lawrence Livermore National Laboratory discovered that by deforesting the entire world, the amount of carbon dioxide would double by 2100. But instead of a great rise in global temperature, their models determined that cutting down all the world's trees would cause the world to cool by 0.3 degrees C (a bit over half a degree Fahrenheit). How could doubling carbon dioxide in the atmosphere decrease the temperature? Doesn't that run counter to everything we know about global warming — that pumping more carbon dioxide into the atmosphere causes the ... Read More
Making Solar Cells Cheaper — It Could Be Plastics
August 11, 2008 • By • Leave a Comment
Enough solar energy hits our Earth each day to satisfy all of the world’s energy demands throughout the year. A technology exists — photovoltaics — that is capable of transforming sunlight directly into electricity without any moving parts. The technology has been around for more than 50 years, yet it contributes only 0.1 percent of the all of the energy produced worldwide. High cost has impeded greater market penetration. Silicon, the first material discovered that is capable of converting enough sunlight directly into electricity for practical purposes, has dominated the ... Read More
Solar Building a Wise, and Ancient, Philosophy
April 21, 2008 • By • 1 Comment
Stroll the streets of America and it’s quickly obvious that few have cared about placing homes and other buildings in regard to the sun’s position during the year. The feeling has been just turn a switch and an air conditioner or a heater will make the space comfortable. Homes and buildings consume almost 40 percent of all the energy produced in America. They use more than 70 percent of the electricity generated in the nation, contributing about half of the United States’ carbon emissions. Heating and cooling homes and buildings accounts for half of the energy they use. Simply ... Read More
Did Archimedes Solve Our Energy Crisis?
April 8, 2008 • By • Leave a Comment
Mirrors and lenses properly shaped can concentrate the benign rays of the sun into a powerful flame, something people have known for at least 2,500 years. In the 1500s, for example, in one of his notebooks Leonardo da Vinci suggested boiling water for a dye factory with the heat generated by a curved mirror four miles in diameter! Though the mirror was never built, Leonardo’s mentor, Andrea del Verrocchio, used a much smaller one for soldering. In the 1800s, concern grew over steam engines’ prodigious appetite for fuel. Once they consumed all the coal in Europe, as some people expected, ... Read More
Electrifying the Developed World
March 26, 2008 • By • Leave a Comment
When governments in developed countries began to fund photovoltaic projects, they missed the uniqueness of the technology and treated it like any other generator of electricity, tending to favor large-scale centralized over building-by-building installations. But the modular nature of photovoltaics allows solar cells to be tailored for the electrical demand on-site, avoiding both the capital costs of building a centralized power plant and the power losses that occur in transmission. Furthermore, photovoltaics, unlike such power plants run by turbogenerators as gas-, nuclear- or oil-fired ... Read More
Solar Cells From Space to Earth
March 25, 2008 • By • 1 Comment
Few inventions in the history of Bell Laboratories evoked as much media attention and public excitement as 1954’s announcement of the breakthrough in solar cells. U.S. News & World Report, for example, speculated excitedly that the silicon solar cell “may provide more power than all the world’s coal, oil and uranium.” Engineers, according to the article, “are dreaming of silicon powerhouses. Their future — limitless.” Unfortunately, the technical breakthrough at Bell could not overcome economics. With a one-watt cell costing $286 at the time ($2,244 in 2008 dollars), a ... Read More
Photovoltaics: A Bright Idea
March 24, 2008 • By • Leave a Comment
Scientists have come up with a seemingly magical way of changing the sun’s energy — not its heat — into electricity. They call the technology photovoltaics — the direct conversion of the sun’s energy into electricity using solar cells thinner than a human hair. Solar cells do away with all the equipment, boilers, turbines, pipes, cooling reservoirs and towers associated with electrical generation. Within a few microns, photons — packets of energy from the sun — silently energize electrons, which then are pushed by the configuration of the photovoltaic material to flow through ... Read More
Workhorse of the Solar Industry
February 22, 2008 • By • 1 Comment
The story of solar water heating began in the 1760s in Geneva, Switzerland, where Horace-Bénédict de Saussure, a Swiss naturalist, observed that it is always hotter when sun rays pass through a glass-covered structure, whether in a coach or a building, than into a site unprotected by such material. To put his hypothesis to scientific scrutiny, in 1767 he built an insulated box, its bottom painted black to absorb as much sun energy as possible, with two panes of glass covering the top — the prototype for all solar water heaters. De Saussure found that when he exposed the box ... Read More
