Utility Scale Solar Power
The sun releases enough power each and every hour to power the world for an entire year! Solar radiation is an endless energy source you can use through a wide selection of distinctive technologies. Many of us are acquainted with smaller solar-power applications, such as that which is used in calculators, water heaters, and even solar power vehicles. But did you know it is also possible to provide solar power on a much bigger scale through the use of energy produced by a solar power plant? These plants function much like any other electricity utility in that they supply power for customers living within a specified radius of the plant's position, and are separated into two basic types of utility scale solar power technology:
Concentrating Solar Power (CSP) Technologies Just like the name infers, a concentrating solar power technology produces electricity by concentrating the sunlight, typically with mirrors. In turn, the mirrors are used to heat up fluids (and occasionally solids), which are then used as steam to operate turbines and other power-producing machines. There are several sub-types of this technology: trough systems, which make use of U-shaped focusing mirrors which have oil pipes running through them. Simply stated, the sun's rays heats the oil, which is then used to boil water to generate steam that drives machinery. A power tower system, on the other hand, uses flat mirrors to track the sun and concentrate its rays onto a receiver on top of a tower. Here, the sunlight heats a liquid (usually molten salt) which in turn produces steam that yields electricity. Since molten salt retains heat, it can be used on days when there is cloud cover or even at night. Last but not least, dish/engine systems are mirrored dishes that follow the sun throughout the day, capture light and concentrate it on to a receiver. The receiver is a part of a combustion engine that has tubes of helium or hydrogen gas running through it. Once the gas is heated up by the sun, it expands and drives pistons, which power an electric generator.
Photovoltaic (PV) Technologies Photovoltaic systems are one of the most common solar power technologies. Instead of converting the sun's rays into heat that subsequently yields power, these systems change the sunlight directly to electricity. Solar cells, only one form of Photovoltaic technology, are constructed of semiconductor materials which cause electrons to flow through the material and generate electrical energy when heated by the sun's rays. However, these cells are far too small for utility purposes. Having said that, a solar array brings together modules of around 40 cells into arrays that may be meters long on each side. Many arrays can be combined to form one large system that will create enough power for a utility. In a concentrated Photovoltaic system, sunlight is targeted on cells using a lens or mirror. These provide a low cost and high efficiency solution that may be scaled up rapidly, all factors which make them an excellent prospect for use on a utility scale.