Duke Energy Carolinas LLC burned 11.4 million tons of coal during the July 2011-June 2012 period, then followed that up with a slightly improved 11.5 million tons of coal burned in the July 2012-June 2013 period.
Those figures are included in monthly fuel consumption reports that this Duke Energy (NYSE: DUK) subsidiary filed on Aug. 9 (covering June 2013 and the prior inclusive 12-month period) and Aug. 15, 2012 (covering June 2012 and the prior inclusive 12-month period) at the North Carolina Utilities Commission.
In the July 2012-June 2013 period, the utility began the period with 4.7 million tons of coal in inventory, received 11.3 million tons, burned 11.5 million tons and ended the 12-month period with 4.5 million tons in inventory. So it was able to make progress in burning down a bloated coal inventory.
In the July 2011-June 2012 period, Duke Energy Carolinas began with an inventory of 3 million tons of coal, received 13.2 million tons, burned only 11.4 million tons, and ended the period with an inflated inventory of 4.7 million tons. So the burn-down of roughly 200,000 tons of coal in inventory in the latest 12-month period didn’t get the utility down to anywhere near where it began the prior twelve-month period.
As recently as calendar 2011, the utility burned 14.3 million tons of coal, so its coal burn lately has been depressed due to various factors like cheap natural gas, emissions control needs and coal unit shutdowns. Notable is that the new, coal-fired Cliffside Unit 6 was commercially available part-way through the July 2012-June 2013 period, but that unit apparently only ate into coal burn at older units and didn’t add to the total burn for the utility.
The fuel reports from both periods also break down various other data, like the capacity factors for the 12-month periods for the various coal units, which are classified as baseload, intermediate and cycling, which are categories based on the age, size, status of emissions controls and other factors that lead to units being used hard, or not so much.
For example, Belews Creek Units 1 and 2, which are baseload units of 1,110 MW apiece, had capacity factors of 76.8% and 63.5%, respectively, in the July 2012-June 2013 period, with the capacity factors for the prior 12-month period coming in at 80.4% and 74.4%, respectively. So each unit ran a bit less in the latest 12-month period. The 825-MW Cliffside Unit 6 had a capacity factor of 70.1% for the time during the July 2012-June 2013 period that it operated.