ON THE GRID
Changing electricity generation mix raises reliability concerns
LITTLE ROCK, ARK. — An unassuming building nestled on a wooded hillside next to the Southwest Power Pool headquarters is key to keeping the lights on for electricity customers in Oklahoma and parts of 13 other states.
What goes on inside the SPP’s operations and data center isn’t top secret, although security is tight and employees have to follow strict reliability, critical infrastructure and electricity market protocols and guidelines. The 36,000-square-foot building itself is designed to withstand a tornado with winds up to 261 miles per hour.
In the windowless grid operations center, a large bank of screens covers one wall, tuned to a couple of news and weather channels. Adjacent screens have color-coded alerts and updates showing which of the region’s 790 power plants are running at that particular moment. Others show maps of the 65,000 miles of transmission lines and realtime electricity prices in the SPP region.
Smaller banks of monitors, desks and computers are arranged around the room, with those operators looking over everything from reliability to transmission service and balancing electricity supply and demand.
The data and operations center
runs around the clock, and every function is mirrored by a redundant data and operations center across the Arkansas River in nearby Maumelle. That allows the Maumelle center to take over the grid oversight roles if something goes wrong at the main center.
Ken Quimby, a senior operations functional specialist for SPP, last week explained to visitors the main goal of the operations and data center.
“We’re here to coordinate the flow of energy within the system,” Quimby said before deadpanning, “Without burning the system down.”
That coordination means keeping careful watch of the voltage and frequency of the electricity on the grid, with only small deviations allowed from the 60-hertz frequency required in North America. It also means making sure SPP members — which include utilities and independent power generators — are following through with their commitments to generate power into the region’s electricity markets.
SPP doesn’t own any generating or transmission assets, but it functions like the air traffic controller for the regional electric grid. The organization doesn’t control the more localized electric distribution systems that lead to customer homes and businesses. Those are still operated by local utilities, cooperatives or municipal systems.
Continuing the airline analogy, Quimby said reserving time on an SPP transmission line is like buying an airplane ticket. A tag, or boarding pass, is created, and getting the transmission service is like taking a seat on the plane.
Other desks in the operations center, like the reliability coordinators, protect the integrity of the system, regardless of costs. Quimby said they’re like sky marshals for the grid, making sure all the parts work together to protect the power grid infrastructure.
Grid reliability
With the rapid rise of wind and solar generation in the past decade, concerns remain about how to best integrate those renewable, intermittent resources into the grid. Secretary of Energy Rick Perry in April ordered a review of how renewables are affecting grid reliability as aging coal and nuclear units continue to get retired.
It’s unclear when that Energy Department report will be publicly released, but several renewable energy groups have already issued “pre-rebuttal” reports. They think the review will try to find justifications for additional coal and nuclear generation. Most coal and nuclear units, and some types of natural gas units, operate around the clock to provide what’s called baseload generation.
The American Wind Energy Association and Advanced Energy Economy released a report earlier this week concluding that the rise of renewables has not endangered power system reliability.
The report, conducted by Analysis Group, a consulting firm, found new natural gas-fired units have become the technology of choice when utilities decide to replace older, coal-fired units. Lower electricity demand, lower costs for renewable energy and higher natural gas production from shale formations have all put market pressures on independent coal plants in regions with competitive electricity markets. The end result is lower electricity prices at the wholesale level, the report found.
“Fundamental market factors are causing everyone to earn lower revenues,” said Paul Hibbard, one of the report’s authors, in a conference call with reporters. “The less economic and less efficient generators are being hit the hardest.”
For its part, SPP has joined with other independent system operators and regional transmission organizations across the country to offer information to Energy Department officials for the reliability review, said SPP spokesman Derek Wingfield.
Wind generated 17 percent of the electricity in the SPP region last year, behind coal at 47.5 percent and natural gas at 22 percent. The rest came from nuclear, hydropower and other sources.
At various times in the past couple of years — mostly in the early morning hours — wind has provided more than 45 percent of the electricity in SPP. On March 19, wind penetration hit 54 percent for a short time.
SPP has more than 16,000 megawatts of wind capacity in its region, which covers a wide swath of the central United States. That represents 19 percent of the generating capacity available in the region.
“We’re able to manage wind generation more effectively than other, smallersystemscanbecause we’ve got a huge pool of resources to draw from,” Bruce Rew, SPP’s vice president of operations, said in February. “With a footprint as broad as ours, even if the wind stops blowing in the upper Great Plains, we can deploy resources waiting in the Midwest and Southwest to make up any sudden deficits.”
SPP released a study last year to show how additional wind in the region could be reliably integrated into the regional grid. Additional transmission planned for the region will help future renewable integration.