Construction of the biggest photovoltaic plant in the United States has been completed.

The 48-megawatt solar farm is 40 miles southeast of Las Vegas and it encompasses more than half a square mile of land, according to published accounts. The energy it generates will be sold by Pacific Gas & Electric.

Sempra Generation of San Diego announced construction has completed. Workers from First Solar of Tempe, Arizona built the plant in less than one year. First Solar also supplied the solar panels that were used for construction.

The Southwest is seeing the construction of even larger solar plants, two of which Sempra is building. Kern County in California will see a 200-megawatt plant while Arizona will see one of 600 megawatts.

Under law, California mandates its utilities to increase solar power. Sempra believes its use of low-cost equipment and it method of construction makes the process even cheaper. As of yet, the company has not disclosed how much the power will cost.

Sempra Generation and San Diego Gas & Electric are sister companies under the ownership of Sempra Energy.