The PNNL project ran for a year ending in March 2007. It updated residential, commercial and municipal customers every five minutes on energy consumption prices through their computers, and let them manage their energy consumption remotely through a grid-friendly appliance controller developed at PNLL. Residential users could set their thermostats, dryers and heaters to respond to certain price points. Municipalities with water-pumping plants had diesel backup generators that were programmed to kick in once grid power became too expensive.

The need for standards

According to PNNL, the controller -- which could be built into home appliances for $5 or less -- can recognize when the electrical grid is straining to meet demand by noting tell-tale fluctuations in current flowing into the host appliance. It then responds by commanding the consumer to briefly scale back power demand. The next big step is to entice appliance manufacturers to build-in such intelligent controllers and to induce the public to demand them.

Some of the fundamental underlying technologies for a smart grid are sketchy. In the U.S. alone the electrical grid comprises more than 14,000 transmission substations and 4,500 switching centers, operated by as many as 3,000 independent companies regulated by state and regional public utility commissions. There is no standard among these entities for how to store and control the flow of energy.

On that score, the National Institute of Standards and Technology (NIST) is working with the Electric Power Research institute (EPRI) toward developing national smart grid standards for energy flow. The Institute of Electrical and Electronics Engineers (IEEE) and the American National Standards Institute (ANSI) are presently working on standards as well.

IEEE P2030 is a case in point. It will tackle interoperability issues, with a goal of producing a high-level electronics guide for the smart grid. Similarly, the ANSI C12.22 open standard defines how to transmit standardized tables of meter data across wired or wireless networks using various transport schemes. Major meter and meter system manufacturers like Itron, Elster, and Trilliant have already said they'll support this ANSI standard.

EPRI is also collaborating with the ZigBee Alliance and the HomePlug Initiative to create a unified AMI and home-area-network (HAN) solution for the smart grid. They're developing a common language for HAN devices to use AMI technology. ZigBee is a global wireless communications language.

In anticipation of these standards, energy meter manufacturers have been working feverishly with hardware and software developers as well as utility companies to prepare for a smarter grid using AMR. Houston's CenterPoint Energy is just one of many utilities using advanced smart grid metering. It plans to deploy 2.4 million meters made by Itron over the next five years. It is working closely with General Electric Digital Energy, IBM, and numerous other companies for smart metering.

Here are a few examples of what's going on in smart metering equipment:

GE is using WiMax-based (36.5-GHz) radios in CenterPoint's system. “Our radios can operate over large distances - — up to tens of miles,” says Larry Sollecito, president and CEO of GE's Digital Energy Enterprise Solution Sector. “This lets us effectively send meter data to the utility's control center,” he adds. Sollecito cautions that to maximize efficiency in an AMR system, the control point (the grid interconnect) must sit close to the user's location. He also cautions, “The electricity system is most efficient operating in a steady state. However, user demand is not steady, so methods must be employed in an AMI that properly factor in these seemingly conflicting issues.”

CenterPoint is using eMeter's EnergyIP meter data management system which captures 15-minute usage data from smart meters and routs it over HANs. eMeter provides software that allows the use of smart gas, electric and water meters used by 300 of the largest utilities worldwide.

Figure 3

Some firms such as Yitran provide transceiver ICs for wireless AMR communications. Its IT700 system-on-chip (SoC) IC PowerLine communication controller is available in two versions: the Protocol Controller Architecture and the Open Solution Architecture. The former has a universal asynchronous receiver/transmitter (UART) and simple command language for a connection to an external host computer. The latter allows use of the IT700's microcontroller peripheral functions such as timers, interrupts, communications interfaces, analog-to-digital converters (ADCs), spare memory resources, and general-purpose I/Os to implement the application, thus eliminating the need for an external host controller.