Uploaded: Tuesday, February 20, 2001 2 p.m.
the lights on:
An ongoing report of local power conditions
What is solar power?
Process has grown less expensive
What is thin and light, won't fry a bird at the slightest touch
and drives PG&E corporate officers crazy?
Power generated by solar cells.
Solar power has been around since 1941, when Russell Ohi devised
the silicon solar cell. A use wasn't found, however, until the space
program created the need for power other than what is generated
That development created a cottage industry that honed and refined
the photovoltaic system to the point where it became viable and
then commonplace. Recently NASA employees spent considerable time
getting a solar array unfolded for the new space station.
In 1996, NASA launched its Near Earth Asteroid Rendezvous (NEAR)
satellite to study an asteroid. The satellite, the first to draw
all of its power from solar energy, has now traveled 2 million miles.
Research conducted to accomplish the scientific programs has refined
solar power's abilities to where it can be used on earth to provide
electricity at a near affordable price.
What are solar cells? They are made of silicon, either single crystalline
or multicrystalline, which convert direct sunlight into electricity.
What is silicon? Try sand--the stuff you find on the beach.
The very thin cell is made up of four layers: a back contact, two
layers of silicon and the blue surface that reflects sunlight. Each
cell generates electricity.
A new product should bring the prices down even further--thin film
cells that cost just 1 percent of the cost of a crystalline cell
and are easy to manufacture, according to the National Institute
for Scientific Education.
A single solar cell doesn't generate enough juice to power much
of anything, except maybe a weak light bulb, a pocket calculator
or a watch. Put a lot of them together and you can power a flashlight,
an AM/FM radio, a laptop computer, a home, a business, or even a
Solar power creates a direct current that has to be converted to
power. That is accomplished by an inverter mounted on the house
or business. Because the electricity has been converted to AC, it
can be put back into the regular power grid.
One array can generate 120 watts. The Ebenhoech home, a Palo Alto
Utilities demonstration project, has 24 Astropower AP 1206 modules,
is rated at 2,880 DC watts and at 2,568 AC watts. Each module generates
120 watts. In all, the panels provide 70 percent of the household's
needs for electricity. The cost in 1999 was $18,188 or $6.32 per
watt before rebate. Gunn High School has large 12 AstroPower LAP-460
panels, rated at 5,520 DC watts or 4,688 AC watts. The cost, in
1999 figures, was $43,408 or $7.80 per DC watt.