CLEAN ELECTRICITY DIRECT FROM
Solar Photovoltaics is the generation of
electricity from sunlight. The solar power gained from photovoltaics can
be used to eliminate the need for purchased electricity (usually electricity
gained from burning fossil fuels) or, if energy gained from photovoltaics
exceeds the home's requirements, the extra electricity can be sold back to the
home's supplier of energy, typically for credit.
Solar power in the United States is the largest available
energy source for the United States, although in 2006 it accounted for less than
0.1% of electricity generation. Renewable resources (solar, wind, geothermal,
hydroelectric, biomass, and waste) provided nearly 12 percent of the nation's
electricity supply in 2003. Due to the eight year extension of the 30%
solar tax credit, it is estimated that an additional 28,000 megawatts (MW) of
solar power will be installed by the end of 2016.
significant application of solar cells was as a back-up power source to the
Vanguard I satellite in 1958, which allowed it to continue transmitting for over
a year after its chemical battery was exhausted. The successful operation
of solar cells on this mission was duplicated in many other Soviet and American
satellites, and by the late 1960s, PV had become the established source of power
for them. After the successful application of solar panels on the Vanguard
satellite it still was not until the energy crisis, in the 1970s, that
photovoltaic solar panels gained use outside of back up power suppliers on
spacecraft. Photovoltaics went on to play an essential part in the success
of early commercial satellites such as Telstar, and they remain vital to the
telecommunications infrastructure today
The high cost of
solar cells limited terrestrial uses throughout the 1960s. This changed in the
early 1970s when prices reached levels that made PV generation competitive in
remote areas without grid access. Early terrestrial uses included powering
telecommunication stations, offshore oil rigs, navigational buoys and railroad
crossings. These off-grid applications accounted for over half of worldwide
installed capacity until 2004.
The 1973 oil
crisis stimulated a rapid rise in the production of PV during the 1970s and
early 1980s. Economies of scale which resulted from increasing production
along with improvements in system performance brought the price of PV down from
100 USD/watt in 1971 to 7 USD/watt in 1985. Steadily falling oil prices
during the early 1980s led to a reduction in funding for photovoltaic R&D and a
discontinuation of the tax credits associated with the Energy Tax Act of 1978.
These factors moderated growth to approximately 15% per year from 1984 through
Beginning with the
surge in coal use which accompanied the Industrial Revolution, energy
consumption has steadily transitioned from wood and biomass to fossil fuels.
The early development of solar technologies starting in the 1860s was driven by
an expectation that coal would soon become scarce. However development of
solar technologies stagnated in the early 20th century in the face of the
increasing availability, economy, and utility of coal and petroleum.
The 1973 oil
embargo and 1979 energy crisis caused a reorganization of energy policies around
the world and brought renewed attention to developing solar technologies.
Deployment strategies focused on incentive programs such as the Federal
Photovoltaic Utilization Program in the US and the Sunshine Program in Japan.
Between 1970 and
1983 photovoltaic installations grew rapidly, but falling oil prices in the
early 1980s moderated the growth of PV from 1984 to 1996. Photovoltaic
production growth has averaged 40% per year since 2000 and installed capacity
reached 10.6 GW at the end of 2007, and 14.73 GW in 2008. Since 2006 it
has been economical for investors to install photovoltaics for free in return
for a long term power purchase agreement. 50% of commercial systems were
installed in this manner in 2007 and it is expected that 90% will by 2009. In August 2009,
plans were announced to build a 2 GW photovoltaic system in Ordos City,
Inner Mongolia, China in four phases consisting of 30 MW in 2010, 970 MW in
2014, and another 1000 MW by 2019. As of June 9, 2009, there is a new
solar thermal power station being built in the Banaskantha district in North
Gujarat. Once completed, it will be the world's largest. Many other large
systems are being designed for installation around the world.
mid-1990s, leadership in the PV sector has shifted from the US to Japan and
Europe. Between 1992 and 1994 Japan increased R&D funding, established net
metering guidelines, and introduced a subsidy program to encourage the
installation of residential PV systems. As a result, PV installations in
the country climbed from 31.2 MW in 1994 to 318 MW in 1999, and worldwide
production growth increased to 30% in the late 1990s.
Germany became the
leading PV market worldwide since revising its feed-in tariffs as part of the
Renewable Energy Sources Act. Installed PV capacity in Germany has risen from
100 MW in 2000 to approximately 4,150 MW at the end of 2007. After 2007,
Spain became the largest PV market after adopting a similar feed-in tariff
structure in 2004, installing almost half of the photovoltaics (45%) in the
world, in 2008, while France, Italy, South Korea and the U.S. have seen rapid
growth recently due to various incentive programs and local market conditions.
The power output of domestic photovoltaic devices is usually described in
kilowatt-peak (kWp) units, as most are from 1 to 10 kW.
Solar installations in recent years have also begun to expand
into residential areas, with governments offering incentive programs to make
"green" energy a more economically viable option. In Canada the RESOP
(Renewable Energy Standard Offer Program), introduced in 2006, and updated in
2009 with the passage of the Green Energy Act, allows residential homeowners in
Ontario with solar panel installations to sell the energy they produce back to
the grid at 42˘/kWh, while drawing power from the grid at
an average rate of 6˘/kWh. The program is designed to
help promote the government's green agenda and lower the strain often placed on
the energy grid at peak hours. In March, 2009 the proposed FIT was
increased to 80˘/kWh for small, roof-top systems (≤10 kW).
Reference: Adapted from Wikipedia®
and used under the
Creative Commons Attribution-ShareAlike License.