A while ago on July 13th, Will Wheaton proposed that the jackhammer that was annoying him at the time be replaced with a new system, that would, instead of using a vibrating hammer to break apart the rocks and concrete of the urban jungle, vaporize it with lasers. Mr. Wheaton feels that this would be quieter, which would disturb his work significantly less.
An interesting idea for sure, and it would certainly change urban renewal forever. Unfortunately, it would come with some strange side effects. For one, lasers do not remove the rock so much as heat it to about 1200 degrees, at which time it chemically changes to carbon dioxide and a fine mist of glowing orange chunks of calcium oxide that will instantly ignite everything they touch. Elaborate safety systems will be required to ensure that your construction workers do not routinely set either themselves, or passing pedestrians, on fire. In order to prevent this, a vacuum system will suck the molten rock into sealed containers for later re-use.
The energy use of this system will be somewhat extreme. Just like water, most rocks resist being heated up and cooled down, especially the limestone that a typical city like the kind Mr. Wheaton lives in is made of. A power plant capable of putting out some 50 megawatts, the energy used by an entire block of Mr. Wheaton's city, would be required to keep the lasers firing, the vacuum pulling, and the other safety systems containing the mess. If we just plugged this in, brownouts would be likely, and portable power systems are unlikely to keep up with the load. At least, not without being louder than the original jackhammers were.
Lastly, this system might not be quieter. While the sound would likely be less irritating than the repetitive, machine-gun-esque thumping of a jackhammer, it would almost certainly make a loud whirring noise while in operation. The vacuum pump that pulls the heated rock away makes noise. The power use makes a loud hum. The rock makes sounds as it heats up, and chemically disintegrates, plus if any water hits the rock, it vaporizes with a loud hiss. The noise would be continuous, and almost certainly distracting.
As irritating as the construction is, the jackhammer is unfortunately a better solution for the moment. As one possible improvement though, many jackhammers are gasoline fired, making them unnecessarily loud. Instead, we will replace the gas motor with an electric one, which makes no sound by itself. The jackhammer's only sound is now the metal hammer striking the rock, making a tapping sound as it does so. If we then insulate the office buildings a little better, the sound will become unnoticeable to the people working above.