ISOs, RTOs Outline Winterization Efforts

In presentations to the Federal Energy Regulatory Commission (FERC), the nation’s regional transmission organizations (RTOs) and independent system operators (ISOs) on Sept. 17 outlined measures they are taking to prevent issues if faced with extreme weather this winter. 

The measures are to prevent widespread generation outages as occurred during the Jan. 6–7, 2014, polar vortex. The North American Electric Reliability Corp. (NERC) last year reported that the extreme cold weather event that engulfed most the nation caused the loss of 19,500 MW of capacity, more than 17,700 MW of which was due to frozen equipment.

While only one balancing authority—South Carolina Electric and Gas—was forced to shed firm load, the event exposed the power sector’s vulnerability to various challenges with natural gas fuel supply and delivery.  NERC issued recommendations on how generators can update power plant weatherization programs. (For more winter planning tips, see POWER‘s October 2014 issue, which includes a collection of stories designed to help power generators prepare their coal, gas, nuclear, and renewable plants for cold weather operations.)

On Sept. 17, the California ISO (CAISO) said completion of key transmission projects should increase flexibility and transfer capability on the CAISO grid, and that drought conditions are not expected to result in local congestion issues this winter. The ISO has also enhanced procedures so that it will provide timely intrastate gas pipelines burn forecasts, and automate information regarding pipeline capacity constraints to monitor generation demand within a constrained gas zone.

The Southwest Power Pool (SPP), which already has an emergency operating plan that allows market participants to notify the balancing authority when fuel could be restricted below certain thresholds, said it had a new weather alert procedure to coordinate communication between SPP and gas pipelines based on weather evaluations of the SPP footprint.

Midcontinent ISO (MISO) said it has also implemented market enhancements since the polar vortex to include gas-electric coordination, enhanced fuel assurance transparency, and market performance.

Meanwhile, PJM Interconnection highlighted that hundreds of megawatts had been retired since last winter, but it did not expect reliability problems. To prepare for winter, it has several studies and drills planned, along with gas/electric coordination meetings.

Noting that 55% of its generating capacity is gas, the New York ISO (NYISO) said it has performed onsite visits of generating stations with a total capacity of 14 GW to discuss winter operations and urge preparedness. In particular, it called for “increased generation testing, cold-weather preventative maintenance, fuel capabilities, and fuel-switching capabilities.” To address transmission constraints, upgrades and preventative maintenance work is scheduled over the next eight months, it said. Significantly, it also said it will increase its total operating reserve requirement from 1,965 MW to 2,620 MW in the day ahead market and real-time dispatch on Nov. 1, 2015.

Yet, NYISO will continue to see winter challenges, it warned, owing to gas availability, and environmental challenges. “Generator switching from gas to oil in some instances result in capacity limitations due to newer, more restrictive NOx emission limitations,” it said. Generators are also reluctant to switch to oil in the face of constraints due to less Northeast refinery capability and upcoming Clean Power Plan carbon targets.

ISO-New England said that its dependence on natural gas soared to 44% in 2014 compared to 15% in 2000 as a result of economic and environmental factors. The region that has been plagued by gas supply bottlenecks said it has worked with stakeholders to develop market enhancements to improve generator performance and strengthen grid reliability.

“ISO-NE is reasonably confident that it can achieve reliable winter operations,” it said. “That said, loss of any major non-gas unit or significant disruptions in gas supply or pipeline capability will create major challenges for ISO operations.”

Sonal Patel, associate editor (@POWERmagazine, @sonalcpatel)



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