A decade ago, the fade for home builders who wanted to be at the cutting edge of the information age was to prewire the house with network cables for your home's computers and peripherals. In retrospect, they got it wrong. The rat's nest of wires associated with your typical computer system is on its way out.
The Demise of Talking Wires
Your keyboard and mouse may be wireless, with a blue tooth wireless connection to the unit that contains your CPU. The connection between your printer and your computer no longer needs a wire. Many people have replaced their fax machine with a number at some anonymous service center that converts a fax into an e-mail attachment and sends it to you over the Internet, and a scanner (which can also be wirelessly attached to your computer and is often part of your printer/copier/fax machine).
There is a good chance that as you read this post over the Internet that you are doing so over a local area wireless connection, and if you are in Cherry Creek North or the 16th Street Mall in Denver, you may even be doing so over a neighborhood wireless connection. Cell phones are, of course, wireless, and even if you still have a landline phone (many college dormitories are considering given up landlines as a standard feature of student rooms), the handset is probably cordless. There are speakers and headphones with wireless connections to your stereo. You might watch cable television, which is, of course, wired, but you might instead watch comparable satellite television, which is, of course, wireless.
Even my bedroom clock has wireless connections. It reads the outdoor temperature from a wireless transmitter in the backyard, and sets itself daily using a radio signal from an atomic clock in Fort Collins.
The basic trend is clear. Information transfer is overwhelmingly moving to a wireless standard. Even the holdouts from the wirless trend, like USB connections and "firewire" connections, prove the rule. They have held out largely because they transfer power as well as information.
Rethinking Power Outlets
Alternating current power systems won the "War of the Currents" back in the late 1800s, because it is easier to transform to high voltages for efficient transmission of power over long distances. But, some recent developments may lead to a direct current counter-revolution a century later.
Change Driving Developments
First, lots of things we power with electricity are becoming more efficient. Compact florescent bulbs and light emitting diodes use much less electricity to produce than same amount of light than traditional incandescent bulbs.
This impact isn't limited to light bulbs either. My cathode ray tube television from thirteen years ago draws 130 watts. My newest computer monitor, a flat screen LCD, draws just 18 watts and isn't all that different in size or function from the television. Computers are also growing less power hungry.
Second, lots of household electrical devices run on low voltage direct current, and require bulky converters to turn household 110 volt alternating current into something it can use. Almost every home computer, ever cordless razor, every cordless drill, every mini-vacuum cleaner runs on DC power. Your phone also runs on DC power transmitted through the phone lines. Everything electrical but the alternator in your car also runs on DC power, and there is a move on to switch car batteries from 12 volts to 36 volts to handle increased power loads in cars. And, every conversion from AC to DC results in lost energy, which is why recharging units get hot (and also a major reason that computers need fans).
In most homes the only electrical devices that still run on AC without converting it to DC power first are the kitchen appliances, the laundry appliances, the fans and the air conditioner.
Third, many of the DC powered electrical items need to be protected from power outs, brownouts and power surges, which are a fact of life if your power comes directly from the power grid. Thus, computer owners routinely purchase surge protectors and uninterruptable power supplies for their computers and peripherals.
In contrast, most of the AC powered electrical items in a typical house, which also tend to be the real power hogs, like ovens and dryers and air conditioners, are not nearly so sensitive to brief power interruptions and irregularities. If the power to your computer goes out for a minute and you don't have some form of battery backup, you lose all your work. If the power to your air conditioner goes out for a minute, you still receive 98% of the cooling you would have otherwise that hour, maybe more because thermostats keep air conditioners from working continuously anyway and it may just adjust the thermostat timing without changing the total cooling.
Fourth, as decades of gradual improvements in consumer and workplace safety have accrued, the danger associated with using high voltage household current AC outlets, instead of low voltage DC power connections, looms larger than it did a century ago when life in general was far more dangerous. Risk apply both to electricians and do it yourselfers working on the systems, and to children and fools at risk of electrocuting themselves through an unholy combination of household power outlets, conductors and water.
Fifth, wireless power supplies at anything more than a few millimeters distance (e.g. inductive heating elements) are pie in the sky technology.
Taken together these facts suggest that it might make sense to rethink how homes, offices and retail businesses are wired.
The Case For AC/DC dual power systems
Instead of a single AC household current system, most homes and businesses might benefit from a dual AC/DC power system. In this system, a couple of rooms, like the kitchen and utility room, would continue to have traditional AC power outlets. But, the rest of the house, would not.
A central household rectifer would convert AC power from the grid (or DC power from local solar panels or fuel cells or windmills or what have you), into DC power which would feed into an uninterruptable power supply for the entire household DC power system. Bedrooms, living rooms, dining rooms, and bathrooms would then have low voltage DC power outlets that would power computers, low watt lights, televisions, stereos, alarm clocks, shavers, mini-vacuum cleaners, electronic ignition systems for natural gas appliances, and the like.
The DC powered gadgets could be smaller, since they would no longer have to have AC to DC power converters or uninterruptable power supplies. The safety risk at DC outlets would be smaller, making child proofing easier. And, energy loss from AC to DC conversion would be eliminated. Yet, since the distances involved from the rectifier to the DC power outlets would be small and take place after local transformers had converted high voltage AC power to low voltage AC power, the transmission effiicency benefits associated with AC power would be largely irrelevant.
The Buried Wire Trend
The hottest issue before the city council in Denver this week was a fight over whether Xcel Energy, the local power company, should bury new lines in the Ruby Hill neighborhood, are put in new overhead lines at greater cost.
As population density increases (reudcing the cost per customer of buried lines), and new subdivisions mandate buried lines, the buried line camp is gaining ground. Overhead power lines are cheaper to put up in the first place (by almost an order of magnitude), but they are much more expensive to maintain through tree trimming and repairs required by weather conditions, and when overhead lines go down in storms, they put lives at risk and disrupt the power grid.
The X Factors
One development could dramatically impact the future of power lines. The holy grail for inventors these days is not a better mousetrap, but a better battery.
Better batteries are the key technology necessary to create competitive electric car, to allow ephemeral renewable power sources like wind and solar power to be useful for meeting base power needs, and to allow the easy development of off the grid homes. Better batteries would eliminate the need for many rooms in a home to be wired at all. Already, you can buy wireless lightbulbs that are battery powered -- you replace the battery when you replace the burnt out bulb.
A second development that could dramatically impact the future of power lines is the evolution of the high temperature superconductor.
Room temperature superconductors will probably never be developed. But, even the highest temperature superconductors today, with a well insulated cooling system, could allow utilities to generate power for the grid much further from the places where it will be used, with less energy loss in transmission, allowing utilities to engage in such tricks as turning solar power into a 24 hour a day energy source. Superconducting loops could also act as a form of energy storage. And, by eliminating the raison d'etre of AC transmission lines, which is low power loss during transmission through the use of easy transformations to high voltage, superconductors could even fundamentally upset the status quo in the war of the currents, making DC power more attractive in a wide range of applications.
Wired magazine may soon find that its name no longer captures the leading edge of technology. The only real question is how far the wireless trend will go.