Conversion of electromagnetic radiation from the sun into other forms of energy drives most processes on Earth. Plants generate chemical energy from sunlight during...
PhotovoltaicsLast Updated on 2014-06-10 18:44:01
In recent decades the imminence of an energy crisis has become a common discussion topic. We will eventually deplete all fossil fuels that can be economically extracted. Depletion is not the only issue involved in the use of fossil fuels; the combustion process releases carbon dioxide which can or is changing global climate. Fossil fuels, such as coal, natural gas, and oil, are the most common energy sources used today. When combusted to create energy, these fuels release large amounts of carbon dioxide and other greenhouse gases. These emissions cause a warming effect on the planet. The exact results of this warming are not certain, but most predictions verge on the catastrophic.
In order to curb this warming effect and free ourselves from fossil fuel use, we must reduce, and ultimately replace, them as an energy source. One promising renewable energy source involves capturing... More »
Photovoltaic energy valuation modelLast Updated on 2012-02-01 00:00:00
Photovoltaic Energy Valuation Model
Sandia National Laboratories in collaboration with Solar Power Electric™ has developed PV ValueTM, an electronic form to standardize appraisals of homes and businesses outfitted with photovoltaic (PV) installations. While the tool is licensed for solar PV installations, it could be used for other large green features in a home that generate income, such as wind turbines. The spreadsheet, user manual and webinar explaining the tool are available for download at http://pv.sandia.gov/pvvalue.
The tool has been designed to be used by real estate appraisers, mortgage underwriters, credit analysts, real property assessors, insurance claims adjusters and PV industry sales staff. For appraisers, the inputs specific to PV in the Residential Green and Energy Efficient Addendum can be used as inputs to PV Value™.
Valuing a PV... More »
Solar (Photovoltaic) CellsLast Updated on 2010-12-18 00:00:00
The photovoltaic effect occurs in semiconductors such as silicon or germanium. Semiconductors, as their name implies, are materials through which charged particles move more slowly than through conductors (e.g. metals), but faster than through insulators (e.g., plastics). Infusing small amounts of specific impurities into the crystals of semiconductors enhances their ability to move charges. Certain impurities, such as phosphorus, arsenic, or antimony, facilitate the movement of electrons and other negative charges (n-type), whereas other impurities, such as boron or aluminum, facilitate the movement of positive charges (p-type). Layering n-type and p-type semiconductors upon one another forms a depletion region.
When sunlight strikes a depletion region, electrons in the region become excited and may migrate into the n-type layer while an equal number of positive charges migrate... More »
Solar Power: A Rapidly Expanding Source of Clean EnergyLast Updated on 2010-12-18 00:00:00
Conversion of electromagnetic radiation from the sun into other forms of energy drives most processes on Earth. Plants generate chemical energy from sunlight during photosynthesis; the maximum efficiency of this process in terms of the energy recoverable from sugars versus the energy in the incident sunlight is about 2%, for sugarcane growing in the tropics.  Solar energy is also responsible for air movements that produce wind power and for the evaporation of water from Earth’s surface and its subsequent precipitation that are the bases of hydroelectric power. Solar power as a renewable energy source, however, usually refers to the conversion of electromagnetic energy into electricity directly through photovoltaic cells or indirectly through solar power plants. Additionally, it is also possible to transform sunlight into thermal (heat) energy.
Currently, less than 0.1%... More »
Drag and drop the content to change the order of featured content. The top nine will be displayed.