As summer swings into high gear, the North American Electric Reliability Corp. says energy resources appear sufficient across the electric grid, although areas heavy with wind and solar power could experience brief reliability challenges.

NERC’s 2017 Summer Reliability Assessment said most areas will have adequate energy supplies to meet demand. But it projected a shortfall in reserve margins in New England that could test operations in that region during extreme weather.

Reserve margin levels in Texas, the highest wind-energy producing state, also might be tighter than usual this summer.

In reviewing the assessment, Paul McCurley, chief engineer at NRECA, said high penetrations of wind continue to be the biggest challenge for maintaining reliability in the Electric Reliability Council of Texas, which oversees the state’s grid. Adverse wind conditions could introduce short-term reliability challenges.

“These situations are not expected to be extensive given the operating history to date, but there could be some short-term operating interventions required should wind output fall below certain target output levels,” McCurley said.

McCurley pointed out that very few areas across the grid have high enough levels of inverter-based resources, such as wind and solar energy, to raise concern, but that situation is increasing.

In its assessment, NERC found that, in certain situations, high levels of both utility and consumer-owned solar resources continue to challenge the California ISO, where the “first known major loss of utility-scale resources” occurred last August, triggered in part by a transmission disturbance and a fire-induced fault.

“Issues arising from a contingency situation involving these inverter-based resources show that we have a lot more to learn about operating a power system with significant levels of these types of resources,” said McCurley.

“Electric system planners and operators should be fully aware of the operational risks posed by high levels of these types of resources, and take appropriate actions to counter these risks.”