Wind generation is contributing to congestion in Illinois, Indiana and Ohio, affecting both the Midwest Independent Transmission System Operator (MISO) and the PJM Interconnection.

It is a problem that is only beginning to manifest on the electric grid, but may lead to significant congestion if not addressed, according to panelists at the U.S. Department of Energy’s (DOE) congestion study workshop held in Philadelphia on Dec. 6. The workshop is the first of four the DOE will hold to inform its 2012 national electric transmission congestion study.

“Illinois, Indiana and now northwestern Ohio are seeing a tremendous growth in wind integrations,” said Bob Bradish, head of American Electric Power’s (NYSE:AEP) transmission planning group. “A lot of that is now starting to show in the way of congestion on our system out there.”

There is a disconnect between the transmission planning perspective and resource planning perspective on what the impact of capacity will be on the transmission system, he said.
“Capacity is driven by the resource planning team,” he said. “They have a definition of capacity; they hand it to the transmission team, that team uses that in planning,” Bradish said.

The transmission team plans for peak hours, or when maximum demand will occur on the system. Incorporating assumptions about what the generation and load will be during peak hours in a transmission planner’s model runs into problems when, for example, 4,000 MW of wind power to which the resource planning team had given a capacity rating of 600 MW generates at full capacity.

“When I plan a transmission system that’s capable of 600 MW firm, what do I do with the other 3,400 MW if it shows up?” Bradish said. “It’s happening now and is causing issues on our transmission  grid.”

This is making planning that used to be relatively routine more complex, said Chuck Liebold, PJM’s manager of interregional planning.

“PJM is now recommending transmission upgrades due to light load criteria, which looks at a 50% peak load and is heavily influenced by renewables integration,” Liebold said.
Light load studies are actionable, and can drive new transmission, Bradish told

TransmissionHub on the sidelines of the workshop. PJM has also expanded its operational criteria, “so if there are things going on in your system to cause operational problems for you then that can be brought to PJM’s attention and they can look into possible solutions to deal with that.”

AEP could also build transmission and pay for it itself, he noted. But the nature of eastern demand is such that a congestion issue identified and addressed in the western part of the PJM system, for example, will lead to other points of congestion.

“East economics are so that they want to pull everything from the west; you fix something, they just pull more, so congestion comes back up again,” Bradish said.

AEP sits on the MISO/PJM seam, and while they look closely at their respective systems, there is not much coordination, Bradish said. He noted that due to the nature of the grid, if the wind shows up in MISO, it will flow into PJM, and vice versa.

“If this planning issue is not addressed, we’re going to see a whole bunch more congestion,” Bradish. “I don’t know how or what the DOE can do on this issue, I don’t know how you address it, but it certainly will drive congestion going forward.”

Rosy Lum is Chief Analyst for TransmissionHub, where this story first appeared: http://transmissionhub.com/2011/12/06/wind-power-causing-congestion-in-p... utm_medium=eNL&utm_campaign=THUB_DAILY&utm_term=Original-Member