By Nancy Spring, Senior Editor
A new generation of resources, technologies and devices are being deployed to build what’s called the smart grid. More than just a new super transmission system, the smart grid will transform how electricity providers operate their systems.
“We’re at a point where there are advanced technologies that are becoming more cost-effective,” said Wade Malcolm, smart grid leads, Accenture. “Utilities have been evaluating how they can use these technologies instead of conventional mechanical technologies.”
The smart grid emphasizes interoperability, renewable generation, distributed generation and storage options, including dispersed energy storage with electric vehicles. It’s envisioned as a nationwide network that uses information technology to deliver electricity efficiently, reliably and securely. The lines between generation, transmission, distribution and the consumer will blur.
Sounds like a good thing, but what is it and how will it change the way power is generated and delivered?
What is the Smart Grid?
“Smart grid is a marketing term that is devoid of technical definition,” said Brian Seal, senior project manager, power delivery and utilization, Electric Power Research Institute (EPRI).
For clarity, Seal’s preference would be to use a collection of separate terms to define the four areas he said are discussed most often in relation to the smart grid: the transmission grid, advanced metering infrastructure (AMI), distributed generation and customer engagement.
Common smart grid themes are improved efficiency, improved reliability and engagement of the customer “and just about everyone would say that a smart grid will accommodate the integration of widespread renewables or widespread distributed energy sources,” said Seal.
The smart grid is a modernized, self-monitoring system, based on industry-wide standards, crossing international borders and participating in wholesale energy trading, providing a stable, secure, efficient and environmentally sustainable network—that’s ABB’s vision, said Gary Rackliffe, vice president, smart grids.
“The characteristics of the smart grid are interconnection of renewables, automation, customer participation, self-healing and monitoring, system efficiency and reliability,” said Rackliffe. “The implementation of controllable devices, that’s the smart grid.”
For power generators, the smart grid means managing distributed resources, absorbing energy storage and renewables and getting ready for plug-in hybrid electric vehicles.
Managing Distributed Resources
Distributed generation (DG) is in the forefront of a lot of thought, said Seal. If DG—which includes energy storage, microturbines, fuel cells, electric vehicles, solar energy and to a lesser extent microwind—emerges significantly, it will present a major challenge for the traditional sources of generation.
 Beacon Power is developing a 20 MW flywheel-based energy storage plant in New York. Illustration courtesy Beacon Power. |
EPRI will be involved for the next five years in smart grid demonstrations that focus on the integration of distributed resources by enabling communications that make them controllable and dispatchable.
Who has the best skill set for managing this kind of network?
“When we take generation out of the central hub and spread it out over the countryside, ultimately those resources are best managed with the same type of knowledge and information that people had in the centralized location when they were managing the larger resources,” said Seal.
Second to DG in its impact on the generator would be demand response or load management. ABB’s Rackliffe said demand response has the potential to change load profile and decrease the need for peaking power, which could shift the energy markets.
Generators could soon be managing DG and demand-side resources (loads) in addition to traditional power sources. Smart grid technologies are automated and enable two-way communications, giving power generators the ability to monitor a number of plants and implement control strategies in a fraction of a second. A utility could have much more precise control over its grid, which is what is needed to accommodate some of these new sources of power generation.
“It looks like you’re adding hundreds or thousands of little generators all across the grid and that requires a much different control strategy,” said Accenture’s Malcolm. “When that happens, it changes the role for traditional generation.”
Storage, Power’s Holy Grail
Energy storage could change the nature of how electricity is generated and redefine the way the markets operate.
“Storage has always been the holy grail,” said Chris Hickman, senior vice president, utility solutions, Ice Energy. “If someone can do it cost-effectively, it will change everything.”
The smart grid can use energy storage to levelize load curves for generators because the focus for efficiency is shifted.
“The smart grid creates efficiencies for the grid, not just the site,” said Hickman.
When the search for greater efficiencies is focused on the site, there are a few unintended consequences, said Hickman. The middle part of the load duration curve has been driven to stay flat or go down but there has been no effect on the “peakiness” of the grid. In California, for instance, Hickman said there’s been 15,000 MW of peak load growth for roughly 400 hours a year. “Even at $2,000 a kW installed in California, that’s $30 billion worth of generation assets on the ground for less than 400 hours a year.”
Energy storage can also address the challenge caused by the rapid installation of renewables.
“We’re seeing more investment in storage technologies, which could bring the cost down and at a very large scale with wind and solar, compensate for intermittency,” said Malcolm.
Hickman said there is another compelling reason for wind farms to embrace storage: transmission ratings. Wind projects are rated as if they were delivering all their energy on peak, but 90 percent is actually delivered off peak. Wind should be putting power on the grid at night, not at times of more stress on transmission lines.
In some regions of the country, rapid installation of wind power has created over-generation scenarios. High winds at night during times of low load create more energy than needed. Energy storage could provide an answer.
And Hickman said if wind energy is stored with technologies that are close to the load, that’s even better.
“If you do storage at the site with wind, you don’t solve any of the issues, you make them worse,” said Hickman. “With compressed air energy storage right by a wind farm, for instance, you don’t unload the transmission lines at all.”
In that case, power would be delivered on peak when there’s no capacity to deliver it. But if the wind’s power is produced and transmitted into the distribution network at night for storage closer to the load, it could be delivered on peak from there, without stressing the grid.
Frequency Regulation: Flywheels
As the grid incorporates more renewables and distributed resources, the base load supply will fluctuate more and additional regulation will be needed to keep things in balance. That’s what flywheel plants are designed to do. When there is excess electricity on the grid, it is taken in by the flywheels, ready to release as needed.
“There’s a motor in the flywheel and electricity drives the motor and spins the flywheel’s rim up to its top speed and holds it,” said Gene Hunt, Beacon Power director of corporate communications. “When the grid operator needs some electricity back to keep things in balance, the motor turns into a generator instantly and the generator is powered by the spinning movement. It’s just recycling electricity.”
The Department of Energy is very supportive of flywheel systems for frequency regulation, and has set aside $40 million to $50 million of the money earmarked for energy storage in its grant program for flywheels. Beacon Power Corp. received a conditional commitment from the DOE for a loan guarantee of approximately $43 million to finance more than 60 percent of its planned 20 MW flywheel-based energy storage plant in the New York Independent System Operator’s territory.
Flywheels can react in a few seconds to the system operator’s signal and flywheels are clean and have a low carbon footprint, Hunt said, “but at the end of the day it has to be cheaper.” He said DOE-sponsored studies have shown that flywheels perform regulation for less than fossil fuel plants.
Lithium ion batteries are being demonstrated for frequency regulation, too. Hunt said one of the main differences between batteries and flywheels—which are essentially mechanical kinetic batteries, based on movement not chemicals—is cyclic life, the ability to charge and discharge tens of thousands of times.
The PHEV Wild Card
Plug-in hybrid electric vehicles (PHEVs) will probably be more of a load than a generation source until second- or third-generation technology, when they could serve as localized storage and generation.
FERC has addressed electricity-powered vehicles and their potential affect on the grid and power generators. Large numbers of plug-in vehicles have the potential to provide some ancillary services like distributed energy storage or regulation services when aggregated, said FERC, but maintaining reliable operation of the bulk power system will require some level of control over when and how electric cars draw electricity off of the system.
Charging millions of PHEVs at times of peak electricity usage like hot summer afternoons when electricity is generally more expensive and transmission lines are at capacity is not a good idea.
“It’s important for the utility that the charging be off-peak when possible,” said Joe Barra, director of customer energy resources, Portland General Electric (PGE). “We’re looking at rate structures to encourage that and smart charging to make sure to the degree possible that charging is taking place when it’s most advantageous to the utility and the customer from a cost standpoint.”
In August, PGE’s home town was named one of five test markets for the largest rollout of electric vehicles and an associated charging station network in United States history.
PGE was selected by Electric Transportation Engineering Corp., a unit of ECOtality Inc. The venture received almost $100 million in federal funds to test and analyze electric vehicle usage and charging infrastructure.
One of the most difficult questions to answer is when PHEVs will have an impact. Some utilities think it’s important to prepare for them sooner rather than later.
“We need to focus on what we’re going to do about these PHEVs,” said Dan Hayes, manager of renewable energy and agency communications at Southern Minnesota Municipal Power Agency. “It’s a tsunami coming and it’s going to hit the grid and we need to manage it.”
The impact of PHEVs will be felt first at the utility’s distribution level, said John Clark, electric vehicle management at GridPoint. “This isn’t going to be a problem of generating enough electricity immediately, but it will be a challenge for the distribution network,” he said.
Barra said PGE looked 10 years out and assumed an electric vehicle penetration rate of 10 percent to estimate what kind of generation resources would be needed to provide for electric vehicle charging.
“If we assume that 10 percent of the vehicles were plug-ins by 2020, we’re predicting 50 average MW and if we can get 90 percent of that off peak, we don’t look to be building a lot of generation infrastructure to support it,” said Barra.
Using PHEVs for load shaping can be friendly to the grid and even a benefit. “A plug-in vehicle is a battery on wheels,” said Clark. “Its primary purpose for consumers is transportation and for utilities, storage.”
More Information, More Integration
For some analysts, the outlook for power generation is unambiguous.
“Clearly, we are on a path to zero-carbon energy sources,” said Jon Arnold, managing director, worldwide power and utilities industry, Microsoft Corp. “Generation companies will have to build portfolios that are low-carbon and that means dealing with variable resources like wind.”
As demand grows—in five years, for instance, “when millions of PHEVs come home and plug in,” said Arnold—demand elasticity will be needed. Information technology (IT) becomes key to managing all the gathered data.
“There will be more integration between the grid companies and the generation companies,” said Arnold. “The next challenge is integration of the grid as more of a holistic system, all through IT.”
At the distribution level, ABB’s Gary Rackliffe said distribution management systems are being combined with SCADA and AMI communications for efficiency and reliability.
Increasing the level of automation will enable smarter grids as will the use of power electronics such as high voltage direct current (HVDC) transmission lines for long distances, HVDC light underground/undersea transmission cable lines and static VAR (volt amperes reactive) compensators (SVCs).
“SVCs increase the amount of power you can move across existing transmission lines without adding additional transmission lines by addressing the stability limitations and voltage limitations of transmission lines,” said Rackliffe.
Generators’ Reality Check
There are things the smart grid can and cannot do. From the generator’s standpoint, looking at the timeframe of the control area under consideration is one way to make sense out of it all. Are we talking seconds, minutes or years?
“A dialogue needs to be started about the timing of generation control, from the standpoint of whether it’s moment to moment performance or long-term planning,” said Kiah Harris, principal consultant, Burns and McDonnell.
For frequency and load control, most SCADA systems pull data back every four seconds. To affect that level of generation control with smart meters out at the end-customer’s location is prohibitively expensive and will not likely happen soon, said Harris.
Harris is skeptical about frequency control, too.
“I thought in the beginning that smart grid could be pulled into that space but I don’t think that will ever really come about,” he said.
At the five-to-10-minute reserve level timeframe, Harris said the smart grid is believable. There, demand response can impact generation operations. Money could be saved on reserves, for instance.
The U.S. requires roughly 3 percent of reserves to be in the ready standby, non-spin area. Based on a countrywide total of 800 GW, that’s about 24 GW in capacity in reserve status.
“To the degree we can bring demand response into that timeframe, we can release some of the generation to meet operations or load growth, so that’s a direct benefit,” said Harris.
“What the smart grid essentially is trying to do is extend the control area concept out to the individual customer meter,” said Harris. “It’s difficult just to process all that stuff. I’m not saying it’s impossible, but it won’t be in the next five to 10 years for sure.”
Smart grid technologies will strengthen the grid and change the way we produce and use power. With “smart” technologies, intermittent or distributed sources of power will be absorbed into the mix and a new generation of electric vehicles charged. The lines between generation, transmission, distribution and the consumer will blur. But change will be incremental and—as in almost all chapters of the U.S. electric system’s history—the bulk power system will be reliable, safe and efficient.
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