Energy News
Soliant:
A new
mechanism for focusing light on small areas of photovoltaic
material could make solar power in residential and
commercial applications cheaper than electricity from
the grid in most markets in the next few years. Initial
systems, which can be made at half the cost of conventional
solar panels, are set to start shipping later this
year, says Brad Hines, CTO and founder of Soliant
Energy, a startup based in Pasadena, CA, that has
developed the new modules.
Concentrating
sunlight with mirrors or lenses on a small area cuts
the costs of solar power in part by reducing the amount
of expensive photovoltaic material needed. But while
concentrated solar photovoltaic systems are attractive
for large-scale, ground-based solar farms for utilities,
conventional designs are difficult to mount on rooftops,
where most residential and commercial customers have
space for solar panels. The systems are typically
large and heavy, and they're mounted on posts so that
they can move to track the sun, which makes them more
vulnerable to gusts of wind than ordinary flat solar
panels are.
Soliant
has designed a solar concentrator that tracks the
sun throughout the day but is lighter and not pole-mounted.
The system fits in a rectangular frame and is mounted
to the roof with the same hardware that's used for
conventional flat solar panels. Yet the devices will
likely cost half as much as a conventional solar panel,
says Hines. A second-generation design, which concentrates
light more and uses better photovoltaics, could cost
a quarter as much. He says that a more advanced design
should be ready by 2010.
SunPower:
When
it comes to solar technology, no one is better equipped
to separate the genuine potential from the hype than
the Department of Energy, which spearheads the country's
solar research efforts. So it's worth noting that
the DOE's choice for the brand-new 205-kilowatt solar
installation on the roof of its Washington, D.C.,
headquarters, unveiled in September, was the unique
high-efficiency solar panels built by Silicon Valley-based
SunPower Corporation.
Energy
Secretary Samuel Bodman called the choice "both
practical and symbolic," and he was right. It's
practical because, earlier this year, SunPower's silicon
photovoltaic cells demonstrated an efficiency of 23.4
percent—a record for large-scale, mass-produced
cells. SunPower uses what's called a "back-contact"
design, which means that all the electrical contacts
are on the back of a cell, leaving a larger area on
the front of the cell exposed to the sun. Such designs
have always been efficient, but it's only in the last
few years that manufacturing costs have become competitive.
For SunPower,
at least, the wait is over. With PV cells that the
company boasts as 50 percent more efficient than conventional
crystalline silicon cells, SunPower is moving full
steam ahead, most recently with an agreement to build
a 250-megawatt "solar ranch" in the California
Valley. The project should begin delivering power
in 2010 and will be—at least temporarily—the
largest PV installation in the world.
