But it's an energy source of the past, right? Aren't we moving away from coal to cleaner technologies like solar and wind power?
Well, no. As the chart above, from the International Energy Agency's Clean Energy Progress Report, makes clear, coal is still the world's fastest growing energy source. That chart shows different types of energy on the y-axis, and the amount added by various countries between 2000 and 2008, in exajoules, on the x-axis. Coal is way out ahead of the pack.
So that's clearly a little bit of a bummer.
There are a couple of silver linings to this cloud of carbon. First, it is likely that wind power's growth is growing at a faster rate than that of coal.
But also—and this is pretty exciting—we're just hitting a point called "grid parity" for solar power in certain parts of the world. Grid parity is the point at which power from alternative sources is cost competitive with power from coal-fueled plants. As we hit grid parity for solar we won't have to rely as much on the government to incentivize clean energy. Investing in solar power will have real near-term economic benefits for mindless profit-maximizing power companies. According to a recent Bloomberg article, we've already hit grid parity in many parts of the Middle East, Japan, and California. With the force of the free market behind solar power, we're likely to see an explosion in installations within the next few years.