WHAT A DIFFERENCE A LIGHT BULB MAKES: People in developing countries are leapfrogging our 19th century technology.

There’s a simple technology that transforms our lives every day, and yet we rarely give a passing thought to its existence (unless of course it flares out at an inopportune moment): the light bulb. And yet for more than a billion people in the developing world who lack access to electricity, this simple device can make an unimaginable difference.

[...] Many of the communities without access to regular electricity are now leapfrogging our ancient 1800s technology. The ubiquitous incandescent bulb, the one perfected by Edison more than a century ago, basically works via a filament that, when electricity passes through, burns hot enough to emit light. But about 95 percent of that energy is wasted as heat. As a result, incandescents are being phased out by many governments; the U.S. slowly began phasing them out in 2012. Compact fluorescent lights, or CFLs, were invented in the 1940s and are significantly more energy efficient. But for decades their cooler tone turned off many consumers (though the color has gotten warmer, and CFLs have been replacing incandescents).

Light-emitting diodes, or LEDs, are the top new technology in lighting. When electricity is applied to an LED, electrons jump from one layer of material within the diode to another and give off light. They’re hardy, they last for years, and they’re incredibly energy efficient. The problem is that white LEDs are pricey. Americans might weigh the options and decide: Why shell out around $10 to $20 for an LED, even if it will last perhaps 25 times longer than the cheap incandescent?

But nearly unbreakable LEDs are easily paired with solar power, and so in poor communities, what seems excessive to us becomes a long-lasting investment that bypasses both inefficient incandescents and the lumbering power grid.