Solar energy
Energy from the Sun
Applications of solar energy technology
Solar energy is the light and radiant heat from the Sun that influences Earth's climate and weather and
sustains life. Solar power is the rate of solar energy at a point in time; it is sometimes used as a
synonym for solar energy or more specifically to refer to electricity generated from solar radiation. Since
ancient times solar energy has been harnessed for human use through a range of technologies. Solar
radiation along with secondary solar resources such as wind and wave power, hydroelectricity and
biomass account for most of the available flow of renewable energy on Earth.

Solar energy technologies can provide electrical generation by heat engine or photovoltaic means,
daylighting and space heating in passive solar and active solar buildings, potable water via distillation
and disinfection, hot water, space cooling by absorption or vapor-compression refrigeration, thermal
energy for cooking, and high temperature process heat for industrial purposes.
SEA Groups Ltd.
We harness the power of the sun for our future
Solar . Energy . Application
SEA Groups Ltd.
We harness the power of the sun for our future
Solar . Energy . Application
The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere.
Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land
masses.  The spectrum of solar light at the Earth's surface is mostly spread across the visible and
near-infrared ranges with a small part in the near-ultraviolet.

The absorbed solar light heats the land surface, oceans and atmosphere.  The warm air containing
evaporated water from the oceans rises, driving atmospheric circulation or convection.  When this air
reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain
onto the earth's surface, completing the water cycle.  The latent heat of water condensation amplifies
convection, producing atmospheric phenomena such as cyclones and anti-cyclones.  Wind is a
manifestation of the atmospheric circulation driven by solar energy.  Sunlight absorbed by the oceans
and land masses keeps the surface at an average temperature of 14 °C.  The conversion of solar
energy into chemical energy via photosynthesis produces food, wood and the biomass from which fossil
fuels are derived.

Solar radiation along with secondary solar resources such as wind and wave power, hydroelectricity and
biomass account for 99.97% of the available renewable energy on Earth.  The total solar energy
absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850 zettajoules (ZJ) per
year.  In 2002, this was more energy in one hour than the world used in one year.  Photosynthesis
captures approximately 3 ZJ per year in biomass.  The amount of solar energy reaching the surface of
the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the
Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined.
Solar energy refers primarily to the use of solar radiation for practical ends.  All other renewable
energies other than geothermal derive their energy from energy received from the sun.

Solar technologies are broadly characterized as either passive or active depending on the way they
capture, convert and distribute sunlight.  Active solar techniques use photovoltaic panels, pumps, and
fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with
favorable thermal properties, designing spaces that naturally circulate air, and referencing the position
of a building to the Sun.  Active solar technologies increase the supply of energy and are considered
supply side technologies, while passive solar technologies reduce the need for alternate resources
and are generally considered demand side technologies.

Solar thermal applications
Solar thermal technologies can be used for water heating, space heating, space cooling, process heat
and electrical power generation.

Solar electricity
Sunlight can be converted into electricity using photovoltaics (PV), concentrating solar power (CSP), and
various technologies.  PV has mainly been used to power small and medium-sized applications, from
the calculator powered by a single solar cell to off-grid homes powered by a photovoltaic array.  For
large-scale generation, recently multi-megawatt PV plants are becoming common.  
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