EPB, the public utility in Chattanooga, Tenn., has built a GPON network for voice, video and data, and has also built a smart-grid to better manage power consumption. For more, see the feature story about EPB from November’s print issue of Communications Technology.
The general purpose of a smart grid is to monitor electricity consumption and to manage its delivery to avoid blackouts or brownouts. Smart grids also reduce costs for the utility and for the consumer, and they’re environmentally friendly as well, given the fact that producing electricity via fossil-fuel power stations is a major cause of greenhouse gases in the world.
"From the utility’s perspective, if they can have the end consumer manage their consumption and shift their load so it’s not happening at the peak demand, it allows the utility to not have to put additional capacity on," says Sanket Amberkar, senior manager at Cisco’s smart-grid unit. "For the end consumer, they’re able to operate at a lower price point."
As far as the cost savings of the smart grid are concerned, users often don’t realize that it costs several times more at certain times of day to generate electricity than it does at others, says EPB COO David Wade.
"We as end users all pay for that lack of information," Wade says. "The smart-grid can provide information to users and (help) to develop ways to store energy and use energy at different times when it doesn’t cost as much."
Communications Critical to Smart Grids
In order for the consumer to manage their power, they must have some type of dashboard in their house, says Amberkar. The dashboard ties to different appliances – the furnace, the air conditioner, the clothes dryer and the hot-water heater – in near real time. The dashboard might be connected via a wireless link to a programmable thermostat capable of powering appliances down based on time of day or price signals.
Richard Loveland, director of marketing for wireline networks at Alcatel-Lucent, says this about the EPB project in Chattanooga: "As we went forward with the smart grid, the first thing we had to do was get the communications infrastructure in place in order to do the smart grid."
Amberkar agrees: "For a smart grid, you have to have an overall architecture that goes across all this; it requires a communications network based on Internet protocols."
As part of EPB’s smart grid, the utility is putting in automated switches all around the network so that when a car hits a pole or a tree falls on a line, instead of having to send a person, switches automatically will see the fault currents and will restore service to all but a small amount of customers in the immediate vicinity.
Smart Grid Business Opportunities
With communications being such a critical component of smart grids, it’s a natural for traditional communications suppliers like Alcatel-Lucent and Cisco to create new business units in the smart-grid space. In September, Cisco completed the acquisition of Arch Rock, a company that provides IP-based wireless mesh-network technology for smart-grid applications.
As such, Arch Rock’s technology is designed to enable utilities to connect smart meters and other distributed intelligent devices over a scalable, highly secure, multi-way wireless mesh network.
"Arch Rock’s wireless-mesh technology enhances Cisco’s IP-based, end-to-end smart-grid offerings," noted Laura Ipsen, senior vice president/GM of Cisco’s smart-grid business unit in a recent statement. "This acquisition further positions Cisco as a strategic partner to utilities working to better manage power supply and demand, improve the security and reliability of energy delivery and optimize operational costs."
Cisco’s Amberkar says wireless mesh (aka RF mesh) is one method for creating the communications infrastructure for a smart grid. In Europe, smart-grid communications have been done over the power lines themselves. The EPB project has the benefit of a GPON fiber network.
"With broadband you can send large amounts of data," says Amberkar. "If you’re just doing meter reading, it’s not latency-critical; you can do it once a day or even once an hour. But if you’re doing (energy management) controls, there’s a latency issue; it’s on-demand. After you aggregate a couple hundred homes, you require a bigger pipe. You’re accumulating data from quite a few locations and bringing it back."
– Linda Hardesty