What is Solar Power
• Solar power is the technology of obtaining
usable energy from the light of the Sun.
• Where solar radiation is high enough it can be
used as a genuine replacement to fossil fuels.
• It can also be used where other energy supplies
are absent such as in space.
• Its application is spreading as the environmental
costs and limited supply of other power sources
such as fossil fuels are realized.
Uses of Solar Energy
Solar energy is currently used in a number
• Electricity Generation – Uses
photovoltaics to turn energy from sun into
• Heat – (hot water, cooking, building heat)
• (Sea water desalination)
Types of Solar Technologies
• Many technologies have been developed to make use of
solar radiation. Some of these technologies make direct
use of the solar energy (e.g. to provide light) while others
• Passive Solar – (sunlight –> useable heat for air
• Water heating – Different systems to heat domestic
water or large spaces.
• A solar box cooker traps the sun's energy in an insulated
box; such boxes have been successfully used for
cooking, pasteurization and fruit canning
A solar cooker
• Photovoltaics – (solar cells) Generate electrical energy
• Solar thermal electric power plants - Solar thermal
energy can be focused on a heat exchanger, and
converted in a heat engine to produce electric power or
applied to other industrial processes.
• Solar Ponds – Pools of water with three layers all with
different densities to avoid convection (transfer heat to
ground) which collects and stores heat energy.
insolation, at the
top of Earth's
and at the surface
on a horizontal
square meter .
Availability of Solar Power
• The amount of solar energy intercepted by the
Earth every minute is greater than the amount of
energy the world uses in fossil fuels each year.
• Tropical oceans absorb 560 trillion gigajoules
(GJ) of solar energy each year, equivalent to
1,600 times the world’s annual energy use.
• Annual photosynthesis by the vegetation in the
United States is 50 billion GJ, equivalent to
nearly 60% of the nation’s annual fossil fuel use.
Advantages of Solar Energy
• The amount of sunlight reaching the earth is plentiful
considering the average needs of humans
• Pollution free during use
• Solar electric generation is economically competitive
where grid connection or fuel transport is difficult, costly
• Grid connected solar electricity can be used locally thus
minimizing transmission/distribution losses
• Once the initial capital cost of building a solar power
plant has been spent, operating costs are low when
compared to existing power technologies
Disadvantages of Solar Energy
• Solar cells are costly, requiring a large initial capital
investment. Creating barriers for LEDC’s.
• To get enough energy for larger applications, a large
number of photovoltaic cells is needed. This is both
capital and land intensive.
• It can only be used in transport by a complicated
electrolysis process. (capital expensive)
• Solar cells produce DC which must be converted to AC
when used in currently existing distribution grids. This
incurs an energy loss.
What is Next?????
It is clear that industrialised nations share a need for
electricity and solar can be increasingly used as a clean
alternative to fossil fuels.
The Solar powered car has been the engineers dream
for the last 20 years.