Higher natural gas prices boosted Midcontinent Independent System Operator power prices from June to July, and heavier loads pushed this July's prices above those of July 2015, stakeholders learned Tuesday.
MISO's real-time locational marginal prices averaged $29.73/MWh this July, up from $27.42/MWh in June and $28.87/MWh in July 2015, according to a written report presented by Shawn McFarlane, MISO executive director for strategy and enterprise risk management.
Spot natural gas prices at the Henry Hub averaged $2.79/MMBtu in July, up from $2.43/MMBtu in June and "similar" to the July 2015 average of $2.83/MMBtu, McFarlane said during Tuesday's MISO Informational Forum.
MISO's load totaled 65.4 TWh in July, compared with 59.9 TWh in June and 64.9 TWh in July 2015.
"Temperatures averaged near normal for the month," McFarlane said. "However, as those of us who live in the Midwest realize, above-normal temperatures and severe weather prompted several hot and severe weather alert declarations."
The highest average real-time on-peak LMP was in Michigan this July, at $41.12/MWh, compared with the overall MISO average of $37.10/MWh and the low of $30.24/MWh in MISO's Arkansas area.
Overall, coal-fired generation was on the margin 85.5% of the time, natural gas turbines were marginal 61.8%, natural gas combined-cycle units were marginal 51.1%, wind power was marginal 12.7%, and hydroelectric power was marginal 3.9%. Binding transmission constraints can produce periods when more than one type of unit is marginal in the overall system, so the percentages above exceed 100%.
Wind power provided 4.3% of MISO energy in July, down from 5.9% in June but up from July 2015's 3.3%.
McFarlane did not report systemwide fuel mix for other generation types, but he did provide a fuel mix report for each region.
Coal-fired generation increased its share from June to July in each of MISO's three major regions, from 64.6% to 65% in the Central Region, from 51.7% to 56.3% in the North Region and from 17.2% to 19.7% in the South Region.
Natural gas-fired generation also increased its share or held steady from June to July in each region, moving from 18.3% to 19.1% in the Central Region and from 9.4% to 11.5% in the North Region, with natural gas in the South Region holding steady at 57.3%.
In contrast, nuclear power's share fell or held steady from June to July, moving from 14.1% to 13.3% in the Central Region and from 20.8% to 18.8% in the South Region, and holding steady in the North Region at 13.5%.
Wind's share fell from June to July from 2.1% to 1.6% in the Central Region and from 22.8% to 16.6% in the North Region, while wind contributed no power in the South Region in either period.
