Page data
Keywords Electricity production, Solar, Solar power, electrical, energy, sunlight, photovoltaics
SDG Sustainable Development Goals SDG07 Affordable and clean energy
Authors Ariel O'Callaghan
Pedro Kracht
Published 2008
License CC-BY-SA-4.0
Impact Number of views to this page. Views by admins and bots are not counted. Multiple views during the same session are counted as one. 2,828

Solar power is the conversion of energy from sunlight into electricity. It can be done directly using photovoltaics (PV), indirectly using concentrated solar power, or a combination. Photovoltaic cells convert light into an electric current using the photovoltaic effect. Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus and concentrate a large area of sunlight to a small beam or point.

It is generally considered to be "Green", renewable, sustainable, and environmentally friendly. With an increasing cost of energy and alternative energies, solar power is becoming more economically feasible and important.

History[edit | edit source]

To Catch the Sun is the first book created from this much exclusive Appropedia content on photovoltaics. It is was successfully crowdfunded on Kickstarter. See to get your own copy.

Passive solar building designs have been used for thousands of years so that the walls and floor absorb heat during the day and releas it at night. If you have ever stood in the sun to warm your body up, then you too have harvested energy from the sun for warmth. In fact, the history of the solar energy dates back to 7th century B.C. and multiple events in ancient times have shaped the future discovery of the solar power system, as we know it today..[1] In 1839 a french physicist, Edmond Becquerel, first showed photovoltaic activity. He discovered that electrical current could be increased in certain materials when exposed to light. Albert Einstein built up this finding 66 years later to what we know know as the photoelectric effect. Electrons are emitted from matter due to their absorption of energy from electromagnetic radiation, specifically very short wavelengths such as ultraviolet (UV) radiation.

Photovoltaics[edit | edit source]

Photovoltaics (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels comprising a number of cells containing a photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years.[2][3][4]

As of 2010, solar photovoltaics generates electricity in more than 100 countries and, while yet comprising a tiny fraction of the 4.8 TW total global power-generating capacity from all sources, is the fastest growing power-generation technology in the world. Between 2004 and 2009, grid-connected PV capacity increased at an annual average rate of 60 percent, to some 21 GW.[5] Such installations may be ground-mounted (and sometimes integrated with farming and grazing)[6] or built into the roof or walls of a building, known as Building Integrated Photovoltaics or BIPV for short.[7] Off-grid PV accounts for an additional 3–4 GW.[5]Driven by advances in technology and increases in manufacturing scale and sophistication, the cost of photovoltaics has declined steadily since the first solar cells were manufactured.[8] Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity, have supported solar PV installations in many countries.

Every day across the globe, the sun shines down on the earth. The energy in the photons from the sun can be converted to electrical energy. The term for this process is the photovoltaic effect.

Since the first commercially available solar panel in the 1960´s, photovoltaic (PV) technology has continued to be explored and developed throughout the world (Pratt & Schaeffer 51). The constant development of this technology has resulted in an increasing level of efficiency and PV panels that are more affordable than ever before, though still initially expensive. Today, humans continue to search for new ways to make photovoltaic technology a viable option for everyone throughout the world. Since most of us are not studying the atomic level of this technology, we can help in other ways - by gaining an understanding and spreading that understanding of photovoltaics, as well as by helping others to gain access to solar, or photovoltaic, systems.

This article explores the components of a photovoltaic system, describes their role and importance, and works as a beginning guide to those wishing to invest in a photovoltaic system.

Concentrated solar power[edit | edit source]

Solar power potential for CSP in the United States.
Concentrated Solar Power (CSP) takes the sun's energy and collects it through a series of arrays and then concentrates or focuses it on a location that is the center of the arrays. The energy at that central point becomes very hot, hot enough to melt many metals and to produce steam. Most notable of these arrays are the large installations of heliostats (mirrors), which track the Sun and reflect the radiant energy to a receiver on a tall tower. A very few smaller systems use Fresnel lenses or parabolic reflectors to concentrate the solar thermal energy. There are a lot of advantages of solar power

Heliostats[edit | edit source]

A heliostat is a device that includes a mirror, usually a plane mirror, which turns so as to keep reflecting sunlight toward a predetermined target, compensating for the sun's apparent motions in the sky. The target may be a physical object, distant from the heliostat, or a direction in space. To do this, the reflective surface of the mirror is kept perpendicular to the bisector of the angle between the directions of the sun and the target as seen from the mirror. In almost every case, the target is stationary relative to the heliostat, so the light is reflected in a fixed direction.

The principal uses of heliostats are for daylighting (bringing daylight into a space that would otherwise be poorly illuminated), and in the generation of electricity in solar-thermal power stations. They are also occasionally used, or have been used in the past, in surveying, in astronomy and other sciences, to produce very high temperatures in solar furnaces, to improve illumination for agriculture, and to direct constant sunlight onto solar cookers. During the 19th Century, they were used by painters and other artists in order to provide constant, bright illumination of their subjects.

Heliostats should be distinguished from solar trackers or sun-trackers, which always point directly at the sun in the sky. However, some types of heliostat incorporate sun-trackers, together with additional components to bisect the sun-mirror-target angle.

Solar power tower[edit | edit source]

PS20 and PS10, Seville Spain.
A solar power tower is a type of indirect solar power technology. Solar power is electricity produced from the radiation of the sun. The energy of the sun can be captured and converted into power directly with Photovoltaic solar panels (PV) or indirectly by solar thermal conversion using Concentrated solar power (CSP) technology.[9]CSP technology uses thermal energy from the sun to heat a liquid, such as water or molten salt. This heat transferring liquid is used to vaporize water to the point of steam, which is then used to generate electricity in a traditional turbine-generator. Power plants using CSP technology include parabolic trough, parabolic dish and solar power tower systems.[10]

Achieving economies of scale[edit | edit source]

There is a need to increase demand for photovoltaics such that they can compete with conventional electricity production methods. One innovative idea is to harness the green purchasing power of academic institutions. This has been shown to be potentially quite influential in catalyzing a positive spiral-effect in renewables globally.[11] open access

See also[edit | edit source]

References[edit | edit source]

  1. Superior Solar - History of solar energy, "Solar Energy Timeline - Infographic".
  2. German PV market
  3. BP Solar to Expand Its Solar Cell Plants in Spain and India
  4. Large-Scale, Cheap Solar Electricity
  5. 5.0 5.1 REN21. Renewables 2010 Global Status Report p. 19.
  6. GE Invests, Delivers One of World's Largest Solar Power Plants
  7. Building integrated photovoltaics
  8. Richard M. Swanson. Photovoltaics Power Up, Science, Vol. 324, 15 May 2009, p. 891.
  9. Robles, Pedro. "PS20 Tower". Abengoa Solar. June 12, 2010. [1]
  10. Richter, Dr. Cristoph. "CSP- Technology". SolarPACES. June 12, 2010. [2]
  11. Joshua M. Pearce, "Catalyzing Mass Production of Solar Photovoltaic Cells Using University Driven Green Purchasing", International Journal of Sustainability in Higher Education, 7(4), pp. 425 – 436, 2006.

Interwiki links[edit | edit source]