The first of these charts, showing the drop in the cost of batteries, is from
a study in Nature Climate Change by Bjorn Nykvist and Mans Nilsson. The second, showing the fall in the cost of installing solar panels for electricity generation, is from
a report by Lawrence Berkeley National Laboratories.
These are the two pieces to the global energy revolution. Solar power, after decades of being much too expensive to replace conventional electricity sources, has fallen exponentially in cost. That will allow countries to build solar farms instead of new coal- and gas-burning power plants. At first, the change will come in sunny locales, and in poor countries where energy is expensive. Eventually, though, almost every country will start building solar on a mass scale. The shift is already happening.
Batteries are the other piece of the renewables puzzle. They solve two huge problems -- transportation, and electricity generation intermittency. You can’t really power cars with solar panels, so to replace oil as a fuel for ships and cars, solar will need some energy-dense storage medium like batteries. Also, solar panels can’t generate electricity at night, so batteries help solve this problem.
Importantly, both of these technologies are experiencing relatively steady cost reductions. That implies that progress is due not to huge new breakthrough technologies, but to learning curves. The more solar and batteries we build, the better we get at building them. That means that we don’t have to hope and pray for big breakthroughs -- we just have to wait for the costs to fall enough.