Duke Energy Florida, a subsidiary of Duke Energy, saw its coal generation mix jump to 27.2% in October, up from 26% expected for the month and also up from 22.6% in September, the utility said in a regulatory filing made public Tuesday.
The regulated utility burned 400,000 st of coal in October, or 27.2% of the total burn, up from 372,764 st st projected to be burned in October and 381,792 st burned in September. The monthly burn was also up from 380,566 st burned in the year-ago month, which made up 23.2% of the mix.
The coal generation mix was the second highest month in 2018, only behind 29.5% in February.
Natural gas burn was at 18.45 Bcf in October, or 72.6% of the generation mix, up from 18.32 Bcf, or 73.9% estimated for the month, but down from 23.44 Bcf, or 77.3%, in September, according to the filing published by the Florida Public Service Commission.
In October, Florida city-gate gas prices averaged $3.725/MMBtu, up 9.2% from $3.41/MMBtu in September and up 18.5% from $3.143/MMBtu in the year-ago month, according to S&P Global Platts.
Duke Energy Florida's Crystal River coal-fired plant generated 912,995 MWh of power in October, up 7.2% from its forecast for the month. The plant's Unit 4 generated 440,456 MWh in October, with a capacity factor at 82%, while Unit 5 generated 394,687 MWh at a 74% capacity factor. Unit 2 generated 77,852 MWh of power with a capacity factor of 23%.
Total coal burn this year through October is at 3.29 million st, down 7.2% from 3.54 million st estimated for the period and down 13.4% from 3.8 million st burned in the first 10 months of 2017. Generation mix for coal is at 23.1% through October, down from 26.5% a year ago.
Average fuel cost for coal was at $3.22/MMBtu in October, up from $3.21/MMBtu in September but lower than gas' average cost of $4.61/MMBtu. Through October, average fuel cost for coal averaged $3.23/MMBtu, while gas was at $4.37/MMBtu, compared with $3.44/MMBtu and $4.28/MMBtu, respectively, a year ago.
Coal purchases for the month totaled 364,955 st, down from 372,764 st estimated and also down from 321,638 st purchased in September. The utility has purchased 3.07 million st of coal this year, down 13.1% from 3.54 million st expected for the period and down 21% from 3.89 million st purchased in the first 10 months of 2017.
Delivered coal cost on a unit basis averaged $73.65/st in October, down from $75.81/st expected for the month but up from $73.60/st in September. For the first 10 months of the year, delivered costs are at $74.24/st, down from $75.68/st estimated for the period and $77.65/st in the same period a year ago.
Average heat content was at 11,450 Btu/lb in October, down from 11,463 Btu/lb averaged in September. Through October, cumulative average heat content is at 11,490 Btu/lb, up from 11,270 Btu/lb averaged in the same period a year ago.
At the end of October, Duke Energy Florida's coal inventory was at 676,234 st, or 52 days of supply, compared with 711,279 st, or 56 days, after September. In the year-ago month, stockpiles were at 855,222 st, or 70 days.
In 2017, the utility took deliveries of 1.07 million st of coal from mines in Colorado, Indiana and Kentucky with an average heat content of 11,609 Btu/lb, according to data from the US Energy Information Administration. The sulfur content of the coal averaged 3 lb SO2/MMBtu and cost roughly $69.50/st last year.
