If you haven’t already done so, I recommend reading energy historian Daniel Yergin’s essay in this weekend’s Wall Street Journal. His excellent piece focused on the pace of energy transitions.

The takeaway from Yergin’s essay is that large-scale energy transitions take a very long time – often measured in decades, not years. They just can’t be wished into existence. He wrote:

The steam engine set off the first major transition in world energy. Instead of relying on biomass—wood, agricultural residue and waste—as it had done for more than 400,000 years, humanity began to move to coal.

We think of the 19th century as the era of coal, but as the distinguished Canadian energy economist Vaclav Smil has pointed out, coal only reached 5 percent of world energy supply in 1840, and it didn’t get to 50 percent until about 1900.

The modern oil industry began in 1859, but it took more than a century for oil to eclipse coal as the world’s No. 1 source. “The most important historical lesson,” Dr. Smil says, is that “energy resources require extended periods of development.”

A no less important lesson is that, even as newer sources overtake older ones, they also overlay them; the older hardly go away. Oil may have overtaken coal as the world’s top energy source in the 1960s, but since then, global coal consumption has tripled.

Here’s a graphic representation of the point Yergin and Smil make that offers the long-term perspective surrounding energy transitions. The chart packs a lot of critical information into a small space, so click on it (or click here) for a much larger version that you can study in detail.

Experts such as Smil and former Obama administration official Steven Koonin have written extensively on the topic of energy transitions, pointing out that the scale of the change required often is underappreciated by many observers.

Finally, the Yergin essay contains several mentions of our company that may surprise some readers. These point out that Exxon was an early pioneer of solar energy research, and that the first rechargeable lithium-ion battery – a technology that now powers consumer electronics as well as today’s electric vehicles – was developed in an Exxon laboratory in the 1970s.

Both developments are representative of the advanced research ExxonMobil routinely conducts, directed at helping solve the dual challenge of meeting the world’s energy needs while managing the environmental effects – including climate change – of energy use.

Such research aims at everything from improving the ways we currently search for oil and gas to thinking about the fuels and technologies that will power the world in the decades ahead. ExxonMobil hopes to play our part in providing the affordable and reliable supplies of energy the world will need.