Second of two stories. Read the first story here.
EPB, the city-owned utility in Chattanooga, Tenn., is not your garden-variety power company.
And that has suited it for a unique investigation of the technologies that experts predict will drive the electric power system of the future.
Created as the Electric Power Board of Chattanooga in 1935, EPB was selected last year by the Energy Department to partner with the Oak Ridge National Laboratory in the research project.
ORNL will provide its expertise in high-performance computer modeling, "big data" analysis, cybersecurity and control system operations. EPB’s high-tech network of advanced electricity meters, digital line switches, and private fiber-optic communications network makes it an ideal laboratory for real-world research by ORNL scientists, DOE says.
"For us, it is helping us understand what the future of the electrical system might look like, and trying to help us be ready for it," said Jim Glass, manager of smart grid development for EPB and its 170,000 business and residential customers.
"Our electric grid must deliver reliable, affordable and clean electricity to consumers," said Patricia Hoffman, DOE’s assistant secretary in the Office of Electricity Delivery and Energy Reliability, when the project was announced last October. "This new partnership will help improve our understanding of grid operations in valuable, new ways and represents another important step in moving the nation closer to the grid of the future."
The lessons learned in the project will illuminate the role of advanced technologies in reducing carbon emissions from power plants, the goal of U.S. EPA’s proposed Clean Power Plan.
The North American Electric Reliability Corp. projects that 18 gigawatts of coal-fired generation capacity will be retired by 2020 to meet the Clean Power Plan goals, followed by 18 GW more of capacity between 2020 and 2030, with another 14 to 22 GW that could retire or operate only part-time for economic reasons. There are more coal retirements due to EPA’s controls over toxic plant emissions. Together, the EPA actions could reduce coal-based generation capacity by one-fourth by 2030, some estimates predict.
Distributed solar power and sophisticated power controls within office buildings and homes will be part of the answer, to an extent that is debated today. At any level, they will require new grid hardware and software and operating procedures, which the EPB-ORNL partnership seeks to fathom.
"One of the projects we are pursuing with ORNL is a controller that would help manage solar, energy storage and demand response for equipment behind the customer meter," Glass said.
"If we have a target output, the battery or energy storage would be the balancing agent. There may be times when we are charging the battery, or times when we want to discharge the battery, to maintain a more consistent supply," Glass said.
"We are going to see more distributed, clean, variable systems like photovoltaics," said Thomas King Jr., ORNL’s director sustainable electricity.
"Imagine a cloud coming by in the summertime on an ungodly hot day," he continued. The power output from the solar units suddenly falls, and the temperature dips. A next-generation grid controller could interrelate those events, instantaneously responding to the drop in power by shutting off an air conditioner compressor and perhaps drawing power from a backup or storage energy system, with a customer’s advance approval, King said.
It’s one thing to demonstrate such a quick response capability on one building. But, he asked, how do you make it work for an entire part of a city, controlling the variable solar power and dealing with the situation’s uncertainty?
The solution requires complex calculations that start with a way to throttle down air conditioning in an acceptable way to office building or household occupants, he said. "It means defining in math terms what comfort is," King said. "Maybe that’s temperature and humidity." The number will be different for different buildings. It can be related to weather forecasts and actual conditions, power supply data and other operations benchmarks.
"Whether it’s a building or a microgrid, you are doing the sophisticated math that allows you to optimize the system. When you have multiple buildings and customers in an area, the math becomes very complex," he said. And that is one thing the project aims to do.
A prime research goal for the project is looking at the entirety of the operating data that EPB’s technology generates, King said. "There is a tremendous amount of data. Being able to understand that and do advanced analytics on it" is a top priority, he said.
Room to roam
Like some of its sister publicly owned utilities, EPB has had more running room to develop its utility network than an investor-owned utility may enjoy.
Aided by a $111.5 million smart grid matching grant from DOE’s share of the American Recovery and Reinvestment Act, EPB installed smart meters throughout its service area. It has also installed about 1,200 IntelliRupter automated power line switches that allow operators to speed up recovery from storms. If a tree takes down a line, the switches can send out a signal that pinpoints the location of the damaged area, isolating it and restoring power to neighboring lines that were unscathed.
EPB runs its network on a control system developed by Minneapolis-based Open Systems International, which includes SCADA (supervisory control and data acquisition) and EMS (energy management systems) technologies. The system manages advanced smart grid modeling, analysis and controls, including the power line diagnostic and recovery application used to recover from storm damage.
Because EPB is the city’s communication provider, it has its own fiber optic communications network that it can use to transmit vital data between key points on the system and the control center, lessening the risks of a cyberattack aimed at operating data traveling over a commercial telecommunications network.
Beyond its integrated smart grid, EPB’s "progressive nature" also made it an ideal partner for DOE, said ORNL Director Thom Mason when the project was announced.
Jim Ingraham, EPB’s vice president for strategic research, seconds that idea.
"One of the reasons we have a partnership with DOE [is], I think, we do have a common vision, or the notion that the electricity sector’s business models, and the way we’ve operated our systems for the past 80 years, is in desperate need of modernization," Ingraham said.
"The average American doesn’t really value electricity all that much. It is a bill they pay every month, but they don’t know much about it," he said. The costs and benefits of electricity to consumers are becoming an increasingly complex equation as a utility’s capital spending rises, and as consumers gain more control over their power supplies and face higher if uncertain risks of damaging power outages from human or natural causes.
"DOE is very interested in us as a test bed not only to prove what technologies work, but what is the economics of that, and the impact on daily lives," Ingraham said.