TEN YEARS AGO utility distribution systems faced the threat of aging equipment and the need to enable distributed resources—in this case, independent power producers borne out of deregulation—to connect to the larger grid. Today, utility distribution systems still face the threat of aging equipment and the need to enable a new set of distributed resources—now in the form of backup power, renewable-energy and cogeneration installations—to connect to the larger grid. As they say, the more things change, the more they stay the same.
However, while distribution systems’ current challenges may look similar to those faced a decade ago, both utilities and their customers have new tools for addressing potential problems. First, the experiences of the last 10 years have fostered a growing understanding of the need for standardized connection procedures. Second, manufacturers are now leveraging dramatically less expensive and more powerful microprocessors to give all players more power supply options and greater intelligence into, and control of, actual line and equipment conditions.
Interconnecting with the utility grid was one of the biggest hurdles independent power operators once faced. Utility and regulator requirements varied so widely that equipment manufacturers had difficulty determining what performance standards their products had to meet, so system designers could be left scrambling for options.
A broad spectrum of industry participants has sought to address this issue with a series of standards for interconnecting distributed resources up to 10 MW to the utility grid. The Institute of Electrical and Electronics Engineers (IEEE) Standard 1547, “Standard for Interconnecting Distributed Resources with Electric Power Systems,” was finalized in June 2003, after several years of discussions among a working group of more than 300 members.
“It was a happy day for me,” said Dick DeBlasio, technical manager at the National Renewable Energy Laboratory in Golden, Colo., and the chairman of the 1547 working group, speaking of the moment final consensus was reached. “The process was very arduous.”
But, he said, the working group’s efforts were critical to the continuing evolution of the U.S. electricity market. The need for a standard became obvious as electric utilities began selling off generating facilities and then drawing on new wind-farm, cogeneration and photovoltaic operations. As DeBlasio pointed out, the United States is home to some 3,000 electric utilities whose operations are regulated by 50 different state public utility commissions, and all of these entities had varying requirements for independent entities seeking grid connections.
“There were many, many agreements, many of which disagreed with each other,” he said.
Work has continued on extending 1547 into a family of related standards. The first of these, IEEE 1547.1, “Standard for Conformance Tests Procedures for Equipment Interconnecting Distributed Resources with Electric Power Systems,” was published last June. This document’s requirements, along with some additional safety parameters, formed the foundation for Underwriters Laboratories Standard 1741, “Standard for Inverters, Converters and Controllers for Use in Independent Power Systems,” against which connecting equipment can be tested.
Future 1547 series additions now in planning include an application guide and guidelines for monitoring and control of distributed resources.
The standard is now working its way through the adoption process. It was referenced in the text of the Energy Policy Act of 2005, along with UL 1741, and has been adopted under California’s Rule 21. The PJM Interconnection, a regional transmission organization serving all or part of 13 states also has adopted IEEE 1547. DeBlasio, whose primary interest is in fostering the development of renewable technologies, sees IEEE 1547 as crucial to a cleaner energy future.
“With this standard, we have a tool that we can use in negotiating interconnections with utilities on renewables,” DeBlasio said. “There’s tremendous opportunity here; the interconnection is something that could be a barrier.”
Energy closer to home
Getting past interconnection hurdles is crucial to greater adoption of distributed-generation strategies and potentially huge energy savings. Distributed generation does more than simply add more power to the grid. Bringing energy production closer to the point where it’s actually consumed is also, simply, a more efficient way of operating a power system. Up to 94 percent of available energy is lost through the process of generating, transmitting and distributing electricity under the present-day system, according to Volker Hartkopf, a professor and director of the Center for Building Technology at Carnegie Mellon University’s School of Architecture.
Hartkopf’s research focuses on integrating all aspects of a building’s design, including its mechanical and electrical systems, to maximize efficiency and minimize energy consumption. Generating electricity closer to where it is used can be one aspect of such plans, though Hartkopf warns against depending too heavily on a single technology or approach.
“In this country, everybody thinks there’s going to be some sort of magic bullet,” he said, arguing that current utility pricing structures offer the companies little incentive to explore the many varied technologies that, when combined, could make an impact on how Americans produce and use energy.
Photovoltaics are certainly one of those options, and Greg Brienza, vice president of the Plattsburg, N.Y.-based electrical contracting firm Triangle Electrical Systems Inc., has a firsthand understanding of the difficulties involved in connecting such equipment to the overall grid. His firm has completed numerous photovoltaic installations, and he said not having clearly outlined guidelines has sometimes made it difficult for equipment suppliers to meet utility requirements. Defined specifications, such as those the IEEE 1547 family is attempting to provide, he said, could be a boon to equipment manufacturers and give system installers more product options.
“It sounds like a good starting point,” he said. “I think it helps standardize the equipment, and I think it will give us more choices and probably give the inverter companies more of a chance to qualify their equipment.”
Brienza recently began working with a new product whose success may be built on the platform of uniform standards. GridPoint Connect, developed by Washington, D.C.-based GridPoint, offers a packaged battery-based storage system that is paired with all the connections and controls necessary to interconnect photovoltaic panels or other power-producing resources, including wind turbines or generators, with the incoming utility grid.
“It packages a lot of the components of a system into one location,” Brienza said, noting that installers don’t have to manipulate all the individual batteries, breakers and other parts and pieces such a connection requires. “It integrates all that stuff together and puts an intelligent front end on it, in the form of an OEM P.C.”
His first project with the system, completed recently, was an installation for a 2,500-square-foot residence. The homeowners now can export power back to the grid and have 10 kWh of backup power in the form of a gel-type battery pack, which can be used to keep well pumps, refrigerators and other crucial loads up during an outage. A sophisticated monitoring and control system keeps users informed as to the amount of power remaining at existing load levels.
GridPoint also recently began marketing their product to utilities interested in using all the connected ancillary generators as their own distributed resources, according to Karl Lewis, the company’s chief operating officer. The plan would enable utilities to buy and install the GridPoint units as customer-premise equipment, meaning utilities could depreciate their purchases. Customer agreements would enable the utility to both cut pre-determined loads and draw on individual power reserves. A large enough network—say 100,000 connected households—could offset the need for a new peak-period generating plant, Lewis said.
“The regulators are saying we need to stop building power plants,” Lewis said, adding that current bottlenecks in transmission-line approval and construction underscore the importance of bringing power closer to the people.
“The economic cost of the transmission is starting to exceed the cost of the plant.” EC
ROSS is a freelance writer located in Brewster, Mass. He can be reached at firstname.lastname@example.org