Solar Transportation
(www.aurorasolarcar.com)
Perhaps
you’ve heard of, or even seen, the odd flat looking cars being raced by various
groups around the world. Maybe you’ve heard names like PrISUm, or Aurora (above). These cars are part
of a fleet of futuristic looking cars powered entirely by solar energy, and are
capable of long distance travel at moderate speeds (200miles at 30-40mph), or
short bursts at highway speeds (70mph). Solar cars produce no pollutants of any
kind, operating off of electric engines fueled solely by electricity generated
through the Photovoltaic effect. The products of several revolutions in the
energy industry, these cars provide a glimpse into the changing face of energy
and transportation.
Photovoltaic
effect:
In 1839 a scientist named Edmond Becquerel described the phenomena known as the
photovoltaic (PV) effect. His research showed that certain types of solid matter
produce small amounts of electricity when exposed to light. In the mid-20th
century further research found that the PV effect is a conversion of light
energy into electricity at the atomic level. In the 1950s new materials were
advanced, and the PV effect made it debut in the industrial scene with the
introduction of commercially viable solar arrays. Today solar arrays power
everything from private homes to government satellites.
Solar Panels:
Solar
panels are made up of many individual components known as PV cells. Modern
commercial PV cells typically produce between one and two
Batteries:
One of the major obstacles to Solar powered vehicles
has been storing energy: what do you do on a rainy day? Recent innovations
within the battery industry have the potential to finally provide a solution to
this problem. Currently car batteries are lead-based, and are far too heavy and
inefficient for use in light-weight solar cars. However Nickel-metal-hydride
and Lithium-ion batteries have recently made a big splash in powering handheld
devices such as cameras. While not fully developed, these batteries are approx.
3 times as efficient as lead-based of the same weight. Nickel-metal-hydride battery are particularly interesting because they are
capable of handling heavy electric loads, and have a 500 recharge lifespan.
They do lose 50% of their charge over a span of a year; an issue of only
secondary importance to an auto application.
Other Obstacles:
Major issues that remain unresolved include weight, and space. Solar cars lack
the engine power to move a heavy-framed vehicle such as an
suv or luxury sedan, and no viable solar car has been
designed that can hold more than two people. These are serious limitations to
producing solar cars for a commercial market. The key to these problems lies in
increasing the efficiency of PV cells. Greater efficiency would increase the
power generated, allowing the installation of heavier components. It would also
decrease the amount of surface area needed for arrays, allowing more interior
room. Several new ideas include organic solar cells, and nanotech cells.
Detractors of solar cars have stated that the necessary technological
developments are decades away, but a new government program might mean that the
radical increase in efficiency needed to make solar cars viable may be closer
than many think.
VHESC (Very High
Efficiency Solar Cell)
The Defense Advanced Research Projects Agency’s (DARPA) Advances Technology and
Defense Sciences Offices are currently offering grants in a new project:
development of a PV cell with a minimal efficiency 3 times the commercial
average. According to the Agency, recent developments in engineered biomolecules, and a new method for fabricating structures
on a nanoscale, have the potential to be combined in
an effort to develop an economically feasible PV cell for use on satellites and
other government equipment.
The program is slotted to run for one year, at the end of which participating
teams will be required to submit a minimum of 1000 units each of which are
10cm². The each devise will be required to produce at least .5W, and operate at
a minimal efficiency of 50% when exposed to a solar fluence
of 1 Kw/m².
Grant proposal are due by May 17, 2005.
Secondary Applications of Solar Energy to the Transportation Industry:
Even if cars powered entirely by the sun’s rays never become viable, solar
power could still become a key component in the transportation industry. One
groundbreaking new technology, hydrogen
power, could receive a huge boost from solar power. One of the barriers to
use of hydrogen is the lack of free hydrogen atoms in the lower reaches of
earth’s atmosphere. Very soon solar power could be the best option for the
clean and low-cost production of hydrogen.