Any way you look at it, gravity as an energy source is hard to beat. It's free, it's in endless supply, and you don't have to import it, mine it, refine it or grow it. The very force that keeps you rooted to the ground could end up powering your house some day.
Since the Gravia lamp wouldn't plug into an outlet at all, it's about as "green" a gadget as you're going to find -- except maybe a solar-powered cell-phone charger or wind-powered tent lighting. The device is entirely self-contained, relying solely on human input to trigger the cycle that creates light. There's no outside energy required beyond that which goes into producing the lamp components in the first place.
And those components, according to the inventor, will never need to be replaced -- or at least not in a human lifetime. He estimates the lamp will work for 200 years [source: Dunn]. LED technology, on the other hand, is not quite to the point of the 200-year bulb. You'd have to buy new LEDs as they burn out. The state of that technology, in fact, is the reason why you can't actually go buy this lamp for your home.
In concept, the lamp is an award winner. In reality, it has a ways to go.
To generate enough power to light up those bulbs, the brass weights would have to weigh substantially more than a collective 50 pounds. They'd have to weigh about 2 tons (1.8 metric tons) -- a bit much for your typical human being to lift to the top of the lamp [source: Core77]. LEDs will have to become significantly more efficient before the Gravia lamp becomes a real possibility.
For more information on the Gravia lamp, gravity power and related topics, look over the links on the next page.