General Energy

Energy is measured in joules, but in many fields other units, such as kilowatt-hours, are customary. All units translate to units of work, which is always defined in terms of forces and the distances that the forces act through.

In everyday vernacular energy and power are synonymous; however, scientists and engineers distinguish between them. Technically, power is not the same as energy, but is the rate at which energy is converted (or, at which work is performed).

Thus a hydroelectric plant, by allowing the water above the dam to pass through turbines, converts the water's potential energy into kinetic energy and ultimately into electric energy, whereas the amount of electric energy that is generated per unit of time is the electric power generated.

This industry comprises establishments primarily engaged in the construction of power lines and towers, power plants, and radio, television, and telecommunications transmitting/receiving towers. The work performed may include new work, reconstruction, rehabilitation, and repairs. Specialty trade contractors are included in this group if they are engaged in activities primarily related to power and communication line and related structures construction. All structures (including buildings) that are integral parts of power and communication networks (e.g., transmitting towers, substations, and power plants) are included.