Fuel procurement and environmental limitations are the top obstacles to increasing the flexibility of PJM’s generating fleet, according to survey results released last week.

About 83% of generator operators responding to the survey said they are operating to the limits of their plants’ flexibility. Of the remaining 17%, most cited fuel and emissions limits, with insufficient compensation “a distant third,” PJM said.

The survey was developed in response to what Adam Keech, manager of wholesale market operations, said was a decline in generation flexibility over the last decade.

PJM’s Eric Hsia told the Market Implementation Committee last week 20% of those who said their units were being offered as flexibly as possible reported their flexibility has decreased over time. Among the reasons cited were compensation rules that discourage investment in aging plants, lack of fuel, emission limits and “additional risk of tripping.”

PJM’s next step will be one-on-one meetings with companies to get more details. Hsia said some of the fuel issues are already being addressed by the Gas-Electric Senior Task Force.