Question:
Water vapour may be a greenhouse gas, but it doesn't acumlate in the atmosphere, so unlike CO2 you won't get buildup, just a bit of extra rain as the air can only hold so much water . And the amount of extra water vapour produced would not affect the world climate significatly, just think how much water vapour is released on a sunny day over the pacific ocean.

in detail ?

Answer: I walked through the silent hallways and down the stairs, heading for the kitchen. On the way, I passed the library and paused for a moment. I could see a thick bound document sitting on Kamen's desk. I'd seen it the previous day on my tour with Kamen and knew the cover said "Confidential." I thought about tiptoeing in, flipping through the pages, and reading all about IT. Frankly, it wasn't ethics that held me back, and it wasn't a failure of nerve. I was supposed to care, but I didn't. What I wanted right then, more than anything else, was a glass of water. (What a bizzare statement to end a piece, especially for a 'good' writer like Boels. Well, I am not fooled, and see right through it. He knows exactly what the potential of it is. Powered by Hydrogen, taken from water)

Another Clue: Gumbel: It's between the Internet and cold fusion.

Clayson: Somewhere between the Internet and cold fusion -- Okay.

Gumbel: Cold fusion. That's pretty big. (as we know cold fusion does not work, but if it did, would solve the world's energy needs. A stirling that runs on hydrogen taken from distilled water sure fits that bill! )