In a growing number of states, renewable energy standards have emerged as an effective and popular tool for promoting a cleaner, more diverse, and renewable power supply. These standards generally include specific percentage targets to be achieved by a specific date.

Typically, a states renewable energy standard requires a utilities company to gradually increase the amount of renewable energy resources such as wind, solar, and bioenergy by a percentage amount by a certain date of their overall energy supply. In fact, nearly half of the total wind development installed between 2001 and 2004 has resulted from states renewable energy standard policies. It's estimated that growth of renewable energy is expected to triple within the U.S. during the next ten years.

Referenced Source: BioConversion Blog