During the spring of 1891, in a canyon in the mountains southwest of Telluride, Colo., icy water from the South Fork of the San Miguel River rushed through a funnel-like tube, crashing into and turning a Pelton waterwheel attached to a nearby 100-horsepower generator in the Ames hydropower plant. As the turbine spun, it generated 3,000 volts of alternating electrical current, which was then shipped by copper wire three miles to a huge motor in the Gold King Mill, perched on the side of a treeless slope far above.

Even as the motor roared to life, a battle raged over the future of what would become the electrical grid. On one side was direct current, or DC -- the kind generated by batteries, lightning and static electricity -- which Thomas Edison had used to light up a Manhattan neighborhood in 1882. On the other side of this so-called War of the Currents was AC, alternating current, embodied by Nikola Tesla, the eccentric Croat genius who had worked for and later been spurned by Edison.

Edison, in a morbid fit of desperation, played the danger card. He used alternating current to publicly electrocute house pets, sheep, horses and, finally, a retired circus elephant named Topsy, that, to be fair, had already been sentenced to death for killing three of its trainers. Topsy's demise was immortalized on film, and today you can find a YouTube video of the smoking elephant in all its grainy, demented glory. Yet even fear didn't help Edison's cause. After traveling at useful voltages for about a mile, DC petered out. AC, meanwhile, could be "stepped up" to high voltages in order to push it across long distances, then "stepped down" with transformers for use in home or industry. The Ames power plant, one of the first commercial industrial applications of AC, dealt a severe blow to DC, and was a seed of what today is a mostly AC grid.

The owners of the Ames plant strung new lines from the plant to more mines, then to town and beyond, becoming the Telluride Power Co., which would own and operate several generating stations and hundreds of miles of transmission lines. Similar systems, built by similar utility monopolies, grew up around the nation.

Until World War II, each utility's grid was fairly self-contained, with fossil-fueled or hydroelectric power plants located close to the residents and industries that used their power. But in the middle of the 20th century, as long-distance transmission technology improved, the utilities oozed outward, building huge coal power plants in the Interior West near the mines, which sent power hundreds of miles across mesa and canyon to Los Angeles, San Diego, Phoenix. Meanwhile, each of the three distinct grids -- the Western, Eastern and ERCOT, or Texas -- became more internally interconnected to increase reliability.

The Western Grid's 240,000 megawatts of generating capacity come from sources as varied as dams in British Columbia to coal-fired plants in northern Mexico, traveling on 120,000 miles of high voltage transmission lines, plus countless miles of distribution lines, the smaller wires that deliver power to your home. As it expanded from one-town micro-grids to today's weblike Leviathan, the grid grew in an organic fashion, with new components welded on to the old ones, like additions slapped on to trailers in the rural West. Hydropower from that same Ames plant now travels alongside coal- and solar-generated electrons in transmission lines built in the 1980s.

Operation and regulation of the grid is a similar mishmash. In the late 1970s and early 1980s, as the Bell telecommunications monopoly was dismantled, a similar effort was made to transform electricity from a service provided by monopoly utilities into a commodity traded on an open market. For the first time, non-utilities were able to build power plants, mostly natural gas-fired, and sell power to the utilities. In 1998, California dove into the open-market concept by opening the California Power Exchange. But unscrupulous operators gamed the system, with some producers creating false power shortages in order to up prices, and the infamous Enron engaging in its own crazy scheme of shipping power out of state, then back in, to dodge state price caps. That drove the utilities to the verge of collapse, caused "brownouts," led to the recall of California Gov. Gray Davis and, in 2001, ended the power-exchange experiment.

Today, about 80 percent of California's grid is run by the California Independent System Operator, a nonprofit entity that allows wholesale power producers access to the grid. It's essentially still the open market, though purportedly less prone to gaming than the earlier exchange, and follows the same model as in most of the Eastern and Texas grids. The rest of the West, though, is stuck somewhere in between the old model and the new, with monopolized utilities -- a mixture of investor-owned, municipal and co-ops, each of which is regulated differently -- still running the show.

Federal policy -- or the lack thereof -- hasn't helped. The authors of the 2011 MIT report, The Future of the Electric Grid, bemoan the fact that in other industries such as natural gas, telecommunications and airlines, federal policy was reformed after the 1970s to reflect market realities. "In contrast," they write, "despite dramatic changes in the electric power sector, federal policies established in the 1930s ... still play a central role in that sector." In other words, just as new pieces have been added onto the old grid, new policies have been piled on top of antiquated ones.

It sounds chaotic, and as the San Diego outage and others reveal, it often is. When the H-NG power line shut down back at Palo Verde, the electricity sought out the path of least resistance towards its destination, which in this case was a tangle of lines in the inland desert that weren't equipped to handle such high voltages. Seconds after that arc had crackled over the Yuma substation, lines, transformers and other equipment from Mexico up into the Imperial Valley were pushed to their limits, and began to fail. Some physicists will tell you that this phenomenon is an inevitable consequence of a grid that has evolved to operate under principles of self-organized criticality, prone to the same sort of non-linear, cascading cataclysm as wildfires, avalanches or earthquakes.

But for the most part, this gargantuan contraption is so seamlessly reliable that most of the millions of people who use it forget it exists. A small army of technicians is dedicated to keeping it that way, perching in front of monitors in rarely seen control rooms around the country.