With large solar arrays and wind farms being proposed to connect to transmission and sub-transmission systems, are utility companies sufficiently prepared to handle the challenge of integrating...
Smart Grid, Smart Utility
The intelligent-grid vision is becoming clearer as utilities take incremental steps toward a brighter future.
SCE’s vice president of engineering and technical services. “The vision is an end-to-end process, integrating AMI with distribution automation, substation control, and bulk-transmission control.”
In addition to improving system reliability and efficiency, such capabilities also will allow the utility to provide a host of new services—not just time-of-use (TOU) pricing, but third-party applications that will help customers use electricity infrastructure and resources more efficiently. And such capabilities might allow California utilities to avert the kinds of crises that plagued their systems in 2000 and 2001—in ways that couldn’t happen without a smart grid.
“One can imagine a future in which California has a couple million plug-in hybrid vehicles,” Kelly says. “On a hot day the grid will draw upon those vehicles as distributed power sources. That’s the kind of exciting path that emerges if the grid becomes smarter” (see “ New Load or New Resource? ” December 2006).
CenterPoint Energy-Houston: Texas-Sized Bandwidth
California is not the only hotbed for intelligent-grid development in America. At least two large utilities in Texas—TXU and CenterPoint Energy-Houston—are moving forward with smart-grid projects using broadband-over-power line (BPL) communications technology.
The prospects for BPL got a boost in Texas in late 2005, when legislators enacted language in a cable-TV-related bill (S.B. 5) that cleared the way for utilities to use power lines for communications without running into onerous regulations or costs. A few months later, CenterPoint Energy-Houston announced its plan for a large-scale BPL demonstration in three neighborhoods, as part of a smart-grid strategy for its power system in the city.
CenterPoint teamed up with IBM Global Business Services to develop a hub-and-spoke architecture that uses substations as hubs, with BPL connections radiating out along medium-voltage distribution lines and connecting with Itron OpenWave meters. High-capacity broadband connections—using fiber optics, microwave, or other technology—will connect the substation hubs to a central MDM system.
Unlike a previous CenterPoint project that provided broadband Internet services to consumers, the CenterPoint project is planned strictly for communicating metering and distribution-network data.
“Just making the intelligent grid happen is a big enough challenge,” says Don Cortez, vice president of regulated operations support with CenterPoint Energy-Houston. “Selling broadband to consumers would make it a no-go business schedule.”
When CenterPoint removed the technical and business complexities of creating a new retail broadband service, BPL became an attractive platform for the intelligent grid. BPL is uniquely suited to smart-grid applications, because power lines already connect every device on the network. Additionally, BPL technology provides ample bandwidth—3 to 5 MB per second in CenterPoint’s case—to carry the massive quantities of data the intelligent grid will require.
“One of the major components of the intelligent grid is the communications layer,” Cortez says. “If you don’t have a robust communications layer, you probably can’t make the intelligent grid work very effectively.”
One reason is latency; without broadband connectivity, an intelligent grid must economize bandwidth, and that reduces its real-time functionality. “What really can make the market more efficient is the ability to exercise commands and get feedback immediately, not just for pricing but other things in the system, like air