28-06-2012, 01:24 PM
Photovoltaic Solar Energy Futures
[attachment=25923]
Trend Analysis & Extrapolation
Trend analysis requires that you do more than simply extrapolate the trend forward.
You have to ask, what is causing this trend, and will those causes continue indefinitely?
Are there upper limits to the trend?
What other forces may affect the trend?
At this point trend analysis relies more on subjective judgment rather than objective extrapolation of historical data.
Assuming that the future will be like the past or that past changes will continue in the same direction and rate is a perfectly sensible way to begin trying to understand the future.
It can not, however, be the end of our endeavors, or we would end up with absurd results.
Energy from the Sun
About half the incoming solar energy reaches the Earth's surface.
The Earth receives 174 petawatts (PW) (1015 watts) of incoming solar radiation at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses.
Earth's land surface, oceans and atmosphere absorb solar radiation, and this raises their temperature. Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.
By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived.
Solar Cells Background
1883 - first solar cell built, by Charles Fritts, coated semiconductor selenium with an extremely thin layer of gold to form the junctions.
1954 - Bell Laboratories, experimenting with semiconductors, accidentally found that silicon doped with certain impurities was very sensitive to light. Daryl Chapin, Calvin Fuller and Gerald Pearson, invented the first practical device for converting sunlight into useful electrical power. Resulted in the production of the first practical solar cells with a sunlight energy conversion efficiency of around 6%.
1958 - First spacecraft to use solar panels was US satellite Vanguard 1
PV Solar for Electricity
For the 2 billion people without access to electricity, it would be cheaper to install solar panels than to extend the electrical grid. (The Fund for Renewable Energy Everywhere)
Providing power for villages in developing countries is a fast-growing market for photovoltaics. The United Nations estimates that more than 2 million villages worldwide are without electric power for water supply, refrigeration, lighting, and other basic needs, and the cost of extending the utility grids is prohibitive, $23,000 to $46,000 per kilometer in 1988.
[attachment=25923]
Trend Analysis & Extrapolation
Trend analysis requires that you do more than simply extrapolate the trend forward.
You have to ask, what is causing this trend, and will those causes continue indefinitely?
Are there upper limits to the trend?
What other forces may affect the trend?
At this point trend analysis relies more on subjective judgment rather than objective extrapolation of historical data.
Assuming that the future will be like the past or that past changes will continue in the same direction and rate is a perfectly sensible way to begin trying to understand the future.
It can not, however, be the end of our endeavors, or we would end up with absurd results.
Energy from the Sun
About half the incoming solar energy reaches the Earth's surface.
The Earth receives 174 petawatts (PW) (1015 watts) of incoming solar radiation at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses.
Earth's land surface, oceans and atmosphere absorb solar radiation, and this raises their temperature. Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.
By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived.
Solar Cells Background
1883 - first solar cell built, by Charles Fritts, coated semiconductor selenium with an extremely thin layer of gold to form the junctions.
1954 - Bell Laboratories, experimenting with semiconductors, accidentally found that silicon doped with certain impurities was very sensitive to light. Daryl Chapin, Calvin Fuller and Gerald Pearson, invented the first practical device for converting sunlight into useful electrical power. Resulted in the production of the first practical solar cells with a sunlight energy conversion efficiency of around 6%.
1958 - First spacecraft to use solar panels was US satellite Vanguard 1
PV Solar for Electricity
For the 2 billion people without access to electricity, it would be cheaper to install solar panels than to extend the electrical grid. (The Fund for Renewable Energy Everywhere)
Providing power for villages in developing countries is a fast-growing market for photovoltaics. The United Nations estimates that more than 2 million villages worldwide are without electric power for water supply, refrigeration, lighting, and other basic needs, and the cost of extending the utility grids is prohibitive, $23,000 to $46,000 per kilometer in 1988.