69% of US Electricity from Solar by 2050
Monday, August 3rd, 2009A recent paper in Energy Policy (see 1 below: Fthenakis, Mason, and Zweibel., 2009) proposes this type of vision of generating 69% of US electricity from solar by 2050 (using also large quantities of energy storage technologies such as molten salts and compressed air energy storage).
The authors note that 640,000 km2 of available land area exists in the Southwest US that can be used to for solar power stations (see link on National Renewable Energy Laboratory website for resource maps, but without land restrictions - NREL Solar Maps). This area is 48% of the total area of the included states of California, Nevada, Arizona, and New Mexico - which in total cover 1,320,000 km2. In 2008 approximately 4,100 TWh of electricity were generated in the US. Thus, 69% is approximately 2,840 TWh.
Note that current photovoltaic (PV) and concentrated solar power (CSP) systems can have solar-to-electric conversion efficiencies from 7%-40%, where the high end of the efficiency range is by laboratory multi-junction PV cells under concentrating lenses. As stated by Fthenakis at al. (2009) their projected 2050 solar electricity generation (which is more than 2,870 TWh due to assumed increases in generation each year) would occur from an installed capacity of approximately 5.5 TW of solar generation - 1.5 TW from solar CSP and 4.0 TW from PV. For a 500 MW solar plant the authors estimate 10.6 km2 of land is needed (at 14% efficiency).
Using this ratio of land for all <a href=”http://solarpaneloptions.co.uk/” title=”Solar Panels Options”>solar panels installations</a> projects the 5.5 TW of capacity would need approximately 110,000 km2 of land, or 17% of the available 640,000 km2. Only 2.4% of the sunlight hitting the land needs to be converted to electricity, but 17% of the 640,000 km2 of land would be required for power plants. The reason is that the conversion efficiencies are calculated assuming that the PV
