Tuesday, May 06, 2008

Smart Grids Picking the Bones of BPL

Have you been waiting anxiously next to your electrical outlets for the day when they'll spring to life with broadband Internet service as well as AC power? That day may never come now. It looks like Broadband over Power Line or BPL is fading fast as a consumer or business high speed Internet connection. Much to the chagrin of Amateur Radio operators who have been buzz kills about trying to kill the buzz in their shortwave receivers, BPL isn't going away. It's morphing into a communications service of, by and for the utilities. Perhaps therein lies a compromise that everyone can live with.

The tipping point for BPL deployment may have come with the recent story in the Dallas Morning News that Current Communications is shutting down its BPL service in Dallas that was intended to serve 2 million homes. Well, shutting down isn't quite the right terminology. It's only the consumer Internet users who are going to be kicked off. The installed transmission networking equipment is being sold to Oncor, the Texas electric transmission and distribution company. The existing BPL, plus some planned expansion, will become the communications backbone of Oncor's Smart Grid.

What's a Smart Grid? You know that electric utility power plants are connected to one of several wide area power grids that blanket the nation. That's not exactly a dumb grid arrangement, but if you've been the victim of a power blackout or brownout you might just call it that. The power grids are heavily managed to make sure that electrons being pushed into the wires by thousands of generating stations are matched with an equal number of electrons flowing out of the grid to power homes, factories, businesses, hospitals and street lights. There's a lot of measuring and watching going on, but it's still a very operator intensive control system.

Most of this has to do with the nature of electrical equipment. Over the last century there's been lots of standardization imposed. But it's mostly copper wires, mechanical circuit breakers, electromechanical relays and contactors, and encapsulated transformers lovingly referred to as "pole pigs." Then there's the really big stuff that transports Megawatts at hundreds of thousands of volts across the countryside. Still, lots of copper, iron core transformers and electromechanical switching.

The idea behind a "smart" power grid is to add two-way communications and control to equipment on the electrical grid. That may start with residential and business utility meters that can be read remotely and be expanded to let the power company switch on and off certain customer owned equipment. Some utilities are doing this with air conditioners to reduce line loads so the system won't overload on hot summer days. You let them control your AC usage. They give you a break on your electric bill. Hot water heaters are also being eyed for load management.

Smart Grids can be enhanced with intelligent equipment that will help them manage the diversity of alternative energy generators that individuals and corporations are connecting to the grid. The consumer is becoming a producer. If this trend takes off as expected, management of all these new solar, wind and hydro micro power plants could become a challenge to power companies used to ramping a relative handful of large power generators up and down. With a Smart Grid, they can make sure that the right amount of electricity is coming from and going to the right places, and that the myriad of small scale producers are properly compensated for their contributions. Under computer monitoring and control, kWh rates can vary by day part or even minute by minute.

Ultimately, computer control over a grid communications network can let the electric grid become self-healing. When one circuit, switch or transformer fails, the system can absorb the blow and re-route currents so that consumers stay powered. Why, it's almost like the Internet. Only with lots and lots of power. If you've ever seen the armada of cherry picker trucks lining the roadway after a major storm, with guys in buckets switching connections using long insulated poles, you know how far we are from a truly self-healing grid.

Who's one of the big names in Smart Grid technology? Why, Current of course. If BPL does wind up getting shorted out by huge costs, interference complaints and rapidly advancing alternative DSL, wireless and fiber optic Internet services, Smart Grids can likely sop up all the power line communications capability that Current and others can provide.

But how do you make BPL a good spectrum neighbor? That might prove to be both contentious and tricky, although there is hope. BPL technology is based on OFDM or Orthogonal Frequency Division Multiplexing. That's a transmission technique that replaces one large carrier signal, like a TV or radio station, with dozens or hundreds of smaller carriers spaced up and down the spectrum. The FCC has said that BPL operators have to shut down individual carrier frequencies that cause interference to other services. But a Smart Grid that needs just enough bandwidth to monitor and control what needs controlling may not be as demanding as a consumer impatiently trying to download a full length movie. With clever spectrum management, it might just be possible to transmit utility signaling data on open wires without overpowering weak radio signals that others are listening to.

Follow Telexplainer on Twitter