Oil barons really know how to dig holes in the ground. And they need a better place to put their money than trying to confuse the public about how serious global fever has become. I think they are missing a old-fashioned business opportunity, and a giant one at that.

Drilling wells is exactly what deep geothermal energy is all about: drill down 5 km, pressure-fracture the rock down there, then drill another well into the fracture zone.

At that, they are the experts. The other use of this technique, invented at Los Alamos in 1972, is what the oil barons ought to be embracing: Aim for a deep rock layer (say, granite) that is dry but hot. Push water down one well, harvest the steam up the other. Then run an old-fashioned steam turbine to generate electricity for the plug-in hybrids.

Works anywhere on earth, though some places will require fewer or shallower wells. Hot Fractured Rock goes under various names such as heat mining; it's nothing like the traditional geothermal plants situated at hot springs.

I recently stood next to an electrical generator, big enough to power a city the size of Seattle (about 1,000 megawatts, known as a gigawatt). It was surprisingly small, no larger than a classroom with a tall ceiling.

      The generator’s spinning shaft could be seen where it connected to the steam turbine, next in line. And backing it up were three more turbines, helping to keep that long shaft spinning at 1,800 revolutions every minute.

      The generator doesn’t spin freely because every electrical light and appliance in that gigawatt-sized city is resisting it. It takes a lot of push from the four steam turbines to keep it up to speed. Some power plants create the steam in a boiler heated by burning coal, others by using nuclear fission of uranium-235 to generate the requisite heat. The cleanest method of all is harvesting steam from water sprayed on hot granite a few miles [5 km] underground.