The U.S. has nearly 500,000 miles of transmission lines carrying electricity to consumers. Many of them are more than 50 years old, a concern, as the "design-life" for many of the components - power transformers, circuit breakers, etc. is only 30 to 35 years on average.

So what's being done to make sure the lights stay on?
Experts say it's a combination of building new power plants,
improving older ones and using advanced transmission
technologies. High voltage direct current (HVDC) technology, for example, allows communities to tap into electricity generated miles and miles away....