Despite higher-than-normal temperatures and severe storms, MISO’s grid remained stable over the months of April and May, Senior Manager of Dispatch Steve Swan told the Reliability Subcommittee last week.

Unit commitment was nearly perfect and there were no minimum or maximum generation events, Swan said in presenting the RTO’s monthly operations updates. April’s full report has already been posted, while May’s will be online by June 21.

April’s peak load was 79.5 GW, set on the 26th, while May’s was 95.4 GW, set on the last day of the month.

A 14% jump in natural gas prices at the Henry Hub drove April’s day-ahead energy prices up 16% to $22.49/MWh, but prices remained low because of MISO’s “very strong wind production and low spring-time load levels.”

Despite the uptick, MISO said natural gas costs were still 26% lower in a year-over-year comparison. Henry Hub prices averaged $1.91/MMBtu for April, up from March’s average of $1.67/MMBtu but still lower than the $2.58/MMBtu average a year ago.

Wind turbines produced 4,934 GWh of energy in April, the highest ever for MISO. Wind’s share of MISO electricity production was 10.9%, up from 8.8% in both March 2016 and April 2015.

Use of coal-fired resources continues to trend downward. Coal supplied 38.9% of April’s total energy, down from 40.5% in March and 48.3% in April 2015.

Gas-fired generation was down slightly to 25.3% in April from 26.5% in March. The number still surpasses April 2015’s 18.4% share.

MISO Wants More Response in Frequency Response

The RSC is concerned about the reliability of MISO’s frequency response under a changing resource mix.

The RTO said changes to the fleet, including the retirement of baseload generation, development of utility-scale wind and solar units and increased demand-side resources, could impact its performance.

MISO adviser Ed Skiba said a coordinated issues statement would be submitted to the Steering Committee for consideration in its issues review process.

“Frequency response is one of our key issues. The main thing is we’re trying to stay ahead of how the world evolves,” RSC Chair Tony Jankowski said.

Skiba said staff has seen “overall improved governor response from the fleet” although there were missing answers in most of the 18 governor surveys returned by balancing authorities.

Results showed the average frequency response of the generation fleet was a -0.35% of capacity/0.1-Hz frequency change. MISO said a figure closer to -1%/0.1 Hz is ideal.

In the near term, Skiba said MISO plans to send an abbreviated survey, requiring a limited amount of data.

Monitor: Changes Needed for Reliability

While the Independent Market Monitor’s State of the Market report for 2015 has not been released yet, Potomac Economics Vice President Michael Wander said the report will show that MISO needs market modifications to support reliability.

“Our State of the Market does reach a conclusion that changes are needed both for reliability and efficiency,” Wander told the RSC. “Our results show a significant amount of generator commitment that is missing is actually being scheduled in the look-ahead process.”

Wander said the appendix’s aggregate data sets will be presented to MISO staff for analysis.

— Amanda Durish Cook