One news feed I follow is Today in Energy from the U.S. Energy Information Administration (EIA), where recently the follow fascinating graph was posted
We can see the advent of major industrialization in the US via the major uptake in coal, followed a few generations later by the even more dramatic Age of Oil and then several decades later by a surge in natural gas. The recent shale gas boom has lead, it seems, not only to an uptick in the use of natural gas but also a decline in the use of coal (with attendant positive effects on greenhouse gas emissions).
What I found more interesting however is that “other renewables” had recently surpassed hydroelectric power. This includes biomass, wind, and solar which I find most interesting of all. Using the EIA’s Electricity Data Browser, I looked at electrical power generation due to solar in the past decade. The results for the 2000s was discouraging:
I bet you could fit a sine wave to that pretty well. But something interesting has been happening to solar the past few years, and they have data more recent than 2010:
That’s well over a tripling of net generation! The price of solar is still dropping and a glut of cheap cells is causing various nations (like China) to expand deployment. This isn’t an entirely new trend, either, as this graphic from The Economist shows
It might just be that we’ve recently moved beyond the “knee of the curve” of the exponential growth and the hard takeoff of solar has begun. The recent ebullient period could well be followed by a drought however, as there are still issues like clouds and nighttime (the storage problem, though that’s being worked on by various means). Still, if recent trends continue we might hesitantly project that coal power in Northern America will continue to be squeezed out between cheap gas and cheap sunlight. If solar is really on an exponential the shale gas era could be prematurely snuffed out, or the drop in price of gas could kill plans for still-more-expensive solar power roll-outs. Time will tell.