Electronic Design

Smart-Grid Report Maps Opportunities For U.S. Engineers

In late June, the Electric Power Research Institute (EPRI) released its “Report to NIST on the Smart Grid Interoperability Standards Roadmap.” The National Institute of Standards and Technology (NIST) had engaged EPRI and other Smart Grid stakeholders to develop a draft interimstandards roadmap that NIST could use to begin developing standards. The document runs 291 pages, and the Smart Grid probably offers the potential for as much engineering work in the next few decades as the Internet or the Apollo program provided across a similarly broad range of technical disciplines.

The report comprises a general overview of the efforts to define the Smart Grid, a conceptual model for thinking about it, and its implementation. For example, section four introduces several application areas, such as an automated metering infrastructure (AMI), ways of handling demand response (DR), and an approach to plug-in electric vehicles (PEVs). Other issues covered include cyber security, wide-area situation awareness (WASA), market communications, and distributed generation and energy storage (DG).

The EPRI authors begin by acknowledging that, of the thousand or so people whose input shaped the report, most tended to focus on a subset of what the entity will ultimately be. Undaunted, they offer a definition: “The term ‘Smart Grid’ refers to a modernization of the electricity delivery system so it monitors, protects, and automatically optimizes the operation of its interconnected elements—from the central and distributed generator through the high-voltage network and distribution system, to industrial users and building automation systems, to energy storage installations and to end-use consumers and their thermostats, electric vehicles, appliances, and other household devices.

“The Smart Grid will be characterized by a two-way flow of electricity and information to create an automated, widely distributed energy delivery network. It incorporates into the grid the benefits of distributed computing and communications to deliver real-time information and enable the nearinstantaneous balance of supply and demand at the device level,” it continues.

There will be a host of benefits, but the more concrete ones come down to benefiting electric consumers, utilities, and society in general. Specifically, consumers will be able to “balance their energy consumption with the real-time supply of energy. Variable pricing will provide consumer incentives to install their own infrastructure that supports it. Smart Grid information infrastructure will sustain additional services not available today.”

Meanwhile, utilities “can provide more reliable energy, particularly during challenging emergency conditions, while managing their costs more effectively.” Then, society “benefits from more reliable power... increased efficiencies, and \\[plug-in hybrid vehicle (PHEV)\\] support will reduce environmental costs, including carbon footprint.”

That’s pretty much what I heard from an EPRI speaker at a conference last fall. In plain language, he said that utilities can’t get licenses to build new generating facilities, so they have to keep using what they have. Some of those plants have bigger carbon footprints than others (dams = small carbon footprint; coal plants = big), so they try to bring the dirtier ones online last.

It would be appealing if the utilities could improve on the deals they have with industrial consumers, in which the businesses agree to be subject to rolling brownouts and blackouts at times of high demand (hot summer afternoons) in return for lower rates per kilowatt-hour. The utilities are already doing something like this with residential consumers like me, who have grid-tied solar. A peak-time kilowatt-hour that I put onto the grid is worth about 28 cents. An off-peak kilowatt-hour that I take off to run my dishwasher is worth about seven cents.

At its most complex and comprehensive, the EPRI speaker said that the Smart Grid would turn that into a sort of auction, in which rates would change dynamically based on what generating plants the utility had to put online. Those rates would be continually fed over the power lines to industrial and residential users, whose electrical equipment would decide whether or not to turn on based on the cost per kilowatt-hour. The consumer or plant manager would set the toggle points and hysteresis, implementing overrides when necessary.

The report contains some arresting statements:

• “A Department of Energy study found that the idle capacity of today’s electric power grid could supply 70% of the energy needs of today’s cars and light trucks without adding to generation or transmission capacity—if the vehicles charged during off-peak times.”

• “While the transition to the Smart Grid may unfold over many years, incremental progress along the way can yield significant benefits. In the United States, electric-power generation accounts for about 40% of human-caused emissions of carbon dioxide… If the current power grid were just 5% more efficient, the resultant energy savings would be equivalent to permanently eliminating the fuel consumption and greenhouse gas emissions from 53 million cars.”

• “A critical goal of the Smart Grid is to enable new technologies and support new business models, just as the Internet generated new technologies and business models a decade ago, and just as it continues to do today.”

• “PEV will add significantly to the load that the power system will have to serve, and if no regulation, coordination, and/or incentives are included, then PEV could significantly increase the cost of peak power. \\[However\\] PEV, although still adding to the load, will help balance on- and off-peak loads through shifting when they are charged and also eventually by providing storage and discharging capacity.”

Much of the report addresses the Smart Grid Conceptual Model, a set of diagrams and descriptions that facilitate discussions of the characteristics, uses, behavior, interfaces, requirements, and standards of the Smart Grid; a tool for talking about developing an architecture; and a context in which to analyze interoperation and standards.

This is where the heart of the document lies, as the EPRI authors attempt to work out a first approximation of the actual impact on each of the stakeholders (who are more finely differentiated in the report than in this brief review). The information density is, in fact, quite dense (see the figure).

This is not the electrical power grid of Steinmetz, Tesla, and Westinghouse, but it is potentially more exciting because it does marry electrical power distribution with the technologies that have dominated electrical engineering since the Second World War. The EPRI report discusses microcontroller-based “smart equipment,” new communications protocols, scalable data management, cyber security, and data privacy along with new software applications that “range from low-level control algorithms to massive transaction processing.”

The report isn’t all “happy talk.” It notes, for instance, that whatever has been driving Smart Grid efforts to date, be it legislative and regulatory policies, operational efficiencies, or customer value, various pressures have “caused the industry to perform Smart Grid implementations in fragmented efforts with limited or no stakeholder coordination or agreed-upon standards. As the technology and interoperability standards mature and gain consensus, some early adopters may be faced with ‘sunk costs’ or, at the very least, some serious integration and interoperability issues going forward.”

Essentially, this is the core document that will lie at the heart of most business plans and design specifications affecting EEs for the next couple of decades.


NIST (EPRI REPORT)www.nist.gov/smartgrid/InterimSmartGridRoadmapNISTRestructure.pdf

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