Solar thermal power plants require significantly less space than other technologies to generate the same amount of electricity.
Furthermore, since solar thermal power plants primarily make use of the Earth's dry zones, competition is negligible as far as land utilization is concerned. Purely in terms of figures, less than three percent of the Sahara would be sufficient to meet the world's electricity requirements with solar thermal power plants. The useable areas available in California would suffice to cover California's electricity needs solely using solar thermal power plants. In reality, however, electricity is usually generated using a mix of different energy forms.
The following graph shows the theoretical space requirements per energy source based on the example of the electricity requirements in Texas. (Click on the magnifying glass to enlarge)
Source: State Energy Conservation Office (Fact Sheet No.8)