The 30 million Americans who bought an iPhone or iPod Touch last year know all too well how often they need recharging. One of them, Jerome Kelty, worried about the harm that's doing to the planet.

Kelty, 41, of Lafayette, Colo., calculated that charging those units every other day for a year would put more than 30 million pounds of carbon dioxide, the main cause of global warming, into the atmosphere. So he bought a portable charger kit and with a few simple tools, in less than an hour, modified it to run on solar power. The homemade device charges his iPod Touch in a few hours without batteries or plugging it in, and will work with most other devices with a USB port.

Now Kelty's invention has won a national contest for the best energy-saving idea.

Earthjustice and Instructables.com, an online community of do-it-yourselfers, sponsored the United States of Efficiency contest to give people a creative way of expressing support for new federal energy efficiency standards.

"Individuals can do a lot to fight global warming," said Kelty, who will receive a new, more environmentally friendly Macintosh laptop from Instructables. "I can ride my bike instead of driving my car. I can use more efficient appliances and use solar and wind power whenever possible. An iPod recharger is a small thing, but it adds up." (See how to make it here.)

The United States of Efficiency contest drew hundreds of entries, from a portable wind power generator to an electric motorcycle. Photos and descriptions of the entries will be sent to the Department of Energy, which is currently asking for public comments on new energy efficiency standards for household and commercial appliances. More than 13,000 comments have been sent through the USE website.

One of President Obama's first acts was to call for a revolution in energy efficiency. Simply by making our appliances and electronics use less energy, Americans can save money, create jobs and fight global warming. Efficiency is the fastest, cleanest and cheapest energy source.

Adopting strong national energy efficiency standards could save consumers $16 billion a year in utility bills by 2030. Adopting the strongest achievable efficiency standards for all appliances to be reviewed would eliminate the need for 200 new power plants, and cut emissions of 150 million metric tons of global warming gases each year.

When Kelty's charger is sent to the DOE, it will be accompanied by a letter he wrote to President Obama and Energy Secretary Steven Chu, recounting a bedtime conversation with his 5-year-old son:

We talked about astronauts on the moon, because every five year old boy wants to be an astronaut. After explaining the Apollo missions to my son, I can't help but draw comparisons to the challenges that we face today and how we will overcome them. Right now the greatest challenge we face is the environment.

Americans love a challenge. We possess the intelligence, technology and spirit to accomplish whatever we set our minds to. How we rise to this challenge will define our generation. It is now the responsibility of all citizens to challenge themselves, to become makers, inventors, conservationists and political activists in order to achieve our goal. It is the responsibility of our leaders, political and industrial, to spearhead our efforts to achieving our goal. We only get one shot at this.

Years from now, when my son is telling his son bedtime stories, I would like him to tell his son of the Green Revolution and of the individuals who made it happen.