A recent U.S. Department of Energy report on LEDs reveals that the widespread adoption of the technology over the next 20 years could save 1,488 terawatt-hours of electricity, which at today's (declining) prices, is worth roughly $120 billion.
To put it in perspective: in our connected, power-hungry age, the energy savings of solid-state lighting is the equivalent of 24 new power plants.
Or for the environmentalists out there: the savings would reduce greenhouse gas emissions by 246 million metric tons of carbon.
According to the report, approximately 7 percent of electricity use in the United States is the result of lighting in homes and businesses, a figure significantly less than years past thanks to the transition from incandescent to flourescent lights.
Here's an excerpt from the report (.pdf):
Solid-state lighting (SSL) has the potential to revolutionize the lighting market through the introduction of highly energy-efficient, longer-lasting, versatile light sources, including high-quality white light. Previously relegated to colored-light applications such as traffic signals and exit signs, SSL products are now successfully competing with conventional technologies including incandescent and fluorescent lamps in general illumination applications. [...]
SSL technology continues to advance at a rapid pace, with improvements being achieved in efficacy, light quality, and operating life. In addition, manufacturing improvements and market competition are putting downward pressure on retail prices, benefiting consumers. As industry and government investment continues to improve the performance and reduce the costs associated with this technology, SSL will become more competitive with conventional light sources and can be expected to capture increasing shares of the general illumination market.
Of course, it all starts with regulatory actions by the federal government, driving inefficient products out of the market.
Once SSL technology hits that magic point of parity with what's already on the market -- from initial price and operating cost to maintenance over the lifetime of the product -- the savings will start to roll in.