We haven't crunched the math ourselves, but we found the reasoning in this greentechsolar article highly intriguing nonetheless. Here's the gist of the argument (bolding added for emphasis):
...897 square miles of land [in Kentucky] has been has been flattened by [mountaintop removal coal mining -- MTR]. Therefore, if we merely put PV solar panels on one-fifth of this already cleared land, we would supply ALL of the electricity needs for the entire Commonwealth of Kentucky!
If we covered the entire 897 square miles of cleared MTR space in Kentucky, we could supply nearly 10% of the electricity needs of the entire U.S.!
Additionally, according to Appalachian Voices, a total of 1,160,000 acres (1,813 square miles) of land has been surface mined for coal in the central and southern Appalachian region.
The United States consumed a total of 3.873 trillion kWh of electricity in 2008.
To produce that much electricity in one year from PV solar panels in this region, 8,225 square miles of land would need to be covered. Accordingly, roughly 22% of the electricity consumed in America could be provided by PV solar panels if the 1,813 square miles of land cleared by MTR in Appalachia were covered.
The main point we take away from this article is not so much that solar panels should be installed on this specific land, although that certainly would have a nice poetic justice to it. Instead, the lesson we believe is worth highlighting is that solar energy has the potential to power America, with far less land than people might think. In fact, a technology white paper on solar energy potential by the U.S. Department of the Interior points out that "a desert area in the southwestern United States that measures [100 miles] on a side (0.3% of the land area of the United States) could theoretically meet the electricity needs of the entire country if the solar radiation in that area could be converted to electricity with 10% efficiency.” And, we'd add, that energy would come with no blown-up mountains, no bills to foreign dictators, no harmful emissions in our air and water. That seems like a pretty good trade for our country to make.