Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Wind Power Plants

.
Wind turbines can be installed in single units, in clusters of two to ten turbines, and in large arrays, called wind power plants or wind farms. Wind power plants can contain large numbers of wind turbines. California's Tehachapi Pass contains several wind power plants, each with more than 1,000 wind turbines.

Wind turbines aggregated into wind power plants are thought to generate electricity more economically than single turbines or those in clusters. It can be more cost-effective to operate and maintain large arrays of wind turbines; however, concentrating wind turbines can reduce individual turbine production when turbines upwind disrupt the airflow of turbines downwind.

The arrangement of wind turbines in a wind power plant is often determined by local geography. Wind power plants on flat terrain are often assembled in long parallel rows.

In hilly or mountainous terrain running perpendicular to prevailing winds, designers often line the ridgetops with long rows of wind turbines.

Like conventional power plants, wind farms are an assembly of multiple independent generators—in this case, wind turbines. Although each wind turbine in a wind power plant operates independently, the turbines are typically connected to a central monitoring system. Whether power is produced from two turbines or from two thousand turbines, the power is aggregated and delivered to an electric utility network.