More than 100x cheaper in 35 yearsFor those who still doubt that solar power is about to shift into high gear and play a much bigger role, look at the graph above. It shows the price per watt, starting in 1977 at over $76/watt all the way down to $0.74/watt in 2013. While it's already very competitive with dirty sources of power in large parts of the world, a few more years of this and solar will simply be too cheap to ignore, even without a price on carbon emissions.
You can see a higher-resolution version of the graph here.
It's similar to the graph below, which I've written about before, but it gives a better idea of the magnitude of the drop in price because it uses a linear scale. Notice that on the graph below, each line on the scale represents a halving of costs (from 16 to 8, 8 to 4, etc). So it's the same data, but it's not as intuitive.