Solar's Potential
With current technology, solar energy can supply much of the electricity that our country needs.
A recent study (PDF) by Navigant Consulting estimated the total amount of solar photovoltaics that could be hosted on rooftops across the country. The study eliminated rooftops that were not conducive to siting solar PV for reasons such as shading, insufficient structural support or bad orientation. Even after filtering out approximately 35% of commercial and 78% of residential roof area in the US, the report concluded that by 2010, 711 gigawatts of solar could be located on rooftops across the US, and with growth in construction and increased efficiency of solar panels, the figure could increase to 1,037 gigawatts by 2025.
For reference, only 3 gigawatts of solar has been installed around the world as of 2005. Obviously, we've just scratched the surface of solar's potential.
What does this all mean?
It means that if we can meet our goal of making solar cost competitive with conventional electricity generation, and it becomes a standard on rooftops across the country, solar could meet 74% to 86% of total US residential electricity demands by 2010 and 2025, respectively.
If this solar was used to power a new fleet of electric vehicles or plug-in hybrids, it could provide enough electricity for over 250 million cars to drive 12k miles per year. That's enough to replace the oil we currently import.
We have the technology. The question is — will we use it in time to make a difference?