Solar Energy
Of the total amount of
solar
energy available to the earth, total human usage would be just a little over
1/100th of 1% (0.00012), if all human usage came directly from solar.
Biomass (grass, trees, crops, etc.) capture just under 1/20th of 1%
(0.00047) of the total; wind accounts for about 0.15% (0.00155) of the total;
and, oceans absorb about 74% (0.7403) of the total.
PLANTS
(photosynthesis)
Plants utilize and store solar energy through the process of
photosynthesis.
Most life on Earth depends on the ability of plants to photosynthesize light.
Biomass (materials
derived from plants)
can be used as biofuels,
for power production,
and in making
products what would otherwise be made from fossil fuels. The US Dept.
of Energy says, "Currently,
biomass is the only clean, renewable energy source that can help to
significantly diversify transportation fuels in the U.S." Since
about 71% of the earth's surface is
covered by oceans, it may make a lot of sense to consider
ocean farming of algae for biofuel and food.
FOSSIL FUELS (crude oil, coal, natural
gas, tar sand,
oil shale)
Fossil fuels were also originally created through
plants using solar energy.
Fossil fuels are formed
under heat and pressure from plants and animals (both
herbivory and
carnivore) that died a
long time ago (some say millions or billions of years ago).
WIND ENERGY
The Earth is unevenly heated by the sun. Dry land heats up (and cools
down) more quickly than the seas do. This differential heating drives a
global
atmospheric convection system creating
windy conditions.
Windmills have been used for
over 2000 years to power machinery, pump water, grind grain, etc.
Wind turbines to
generate electricity are a relatively new wind
energy development and are
growing quite rapidly.
By
2010 the World Wind Energy
Association expects
160GW of capacity to be installed worldwide, up from 73.9 GW at the end of
2006, implying an anticipated net growth rate of more than 21% per year.
HYDROPOWER
Water constantly moves through a vast global cycle, evaporating from lakes
and oceans, forming clouds, precipitating as rain or snow, then flowing back
down to the ocean. The energy
of this water cycle, which is driven by the sun, has been used by
waterwheels to power mills and machinery, and by
hydroelectric dams
to generate electricity. Other potential
sources of hydropower are
tides and
waves.
SOLAR LIGHT
Good
architectural design can maximize the use of
natural sun light, which
saves money and can provide a better environment.
SOLAR HEAT
Solar energy can be used to
directly heat water.
China has 80% of the world's
solar heating systems.
In Israel 90% of the homes use this technology. Swimming pools are the
most successful application of
solar hot
water in the USA.
Solar ponds can be used to store solar energy.
Evaporation ponds are used to produce salt from sea water.
A solar
still uses solar energy to
distill
water.
Solar cookers use
sunlight to cook food. A
solar furnace can
achieve temperatures up to 3,000 degrees Celsius.
SOLAR CELL (Photovoltaics)
A
solar cell
is a device that converts light into electricity.
Photovoltaic production
has been doubling every two years, increasing by an average of 48% each
year since 2002, making it the world’s fastest-growing energy technology.
In 2006 about 78% of solar cells were connected to the
electrical grid. The aim of the "Solar America Initiative" is to
achieve grid parity by
2015. Nanosolar
(wiki) says they are
already on the
way to
"making electricity as cheaply from sunlight as from coal."
Note: See this article online, with
hyperlinked references, at: http://www.friendlyinnovators.com/mn/20080325.htm
Next time:
Nuclear Energy
Al Leedahl
Engineering Design Concepts
www.leedahl.com/engineering/design/concepts.htm
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