Houston — Spot power prices and peakload in the Electric Reliability Council of Texas footprint reached multiyear highs for the month of September, boosted by weather-driven higher demand, but prices were down from August levels.
ERCOT North Hub day-ahead on-peak averaged around $112.75/MWh, the highest price for the month of September since at least 2013 and 265% higher than the five-year average price for September. A day-ahead price record of $973/MWh was set September 5. Month on month, ERCOT North Hub fell 39%.
The biggest year-on-year jump occurred in ERCOT West Hub, where spot prices jumped 272% to average near $110.25/MWh. Month on month, ERCOT West Hub fell 40%, the largest month-on-month decline.
Houston Hub rose 255% to average around $110/MWh, which was the smallest year-on-year gain among the ERCOT hubs.
Gas and power prices moved in opposite directions in September. Houston Ship Channel spot gas averaged $2.449/MMBtu during September, 17% higher than the average price in August, but 18% lower year on year.
During September, ERCOT demand peaked at 68,959 MW, a monthly record, according to the grid operator.
ERCOT's monthly peakload was up 7% from September 2018 but was 8% lower than in August, when an all-time record of 74,666 MW was set.
Average temperatures across the ERCOT region were 4 to 7 degrees higher than normal and 3 to 7 degrees higher than last September, according to data from the US National Weather Service.
Accordingly, cooling degree days also exceeded both normal values and last September's values. West Texas, in particular, had a dramatic increase in cooling degree days. In the Midland-Odessa area, there were 80% more cooling degree days than normal in September and 62% more than the same month a year ago.
Throughout the rest of the ERCOT footprint, there were between 39% and 66% more heating degree days than normal. Year on year, cooling degree days increased between 21% and 44%.
After falling for four consecutive months, the wind share of the ERCOT generation mix rose during September. Wind accounted for 16% of ERCOT generation, up from 14% in August and 12% last September. Overall, wind was the third-largest source of ERCOT power generation, behind natural gas and coal.
Natural gas made up 53% of the fuel mix during September, down from 57% in August but up from 49% in September 2018.
Coal generation also ticked up month on month, rising from 18% of the fuel mix in August to 20% in September. Last September, however, coal accounted for 27% of the ERCOT fuel mix.
October forward contracts for power and gas strengthened month on month in September. The ERCOT North Hub October on-peak contract rose 21% month on month to average $32.50/MWh, according to Platts M2MS data. Similarly, the Houston Ship Channel October natural gas contract gained 19% month on month and averaged around $2.463/MMBtu.
Year on year, the ERCOT North Hub October on-peak contract gained 3%. In contrast, the Houston Ship Channel October contract was down 17% year on year.
The latest National Weather Service seasonal outlook, issued September 19, indicated a 40% to 50% probability of above-normal temperatures in the region from October through December.
-- Kelli Ainsworth, firstname.lastname@example.org
-- Edited by Bill Montgomery, email@example.com