Customers across Duke Energy’s service territories felt the chill of winter in early January as snow fell in north Florida, ice accumulated in coastal South Carolina, temperatures fell to record-breaking lows across the Midwest, and the Carolinas were below freezing for nine straight days.
As people huddled inside, they bumped up thermostats to keep their homes toasty, which is an understandable, but energy-guzzling act.
The demand to heat homes and businesses led to all-time highs in use for Duke Energy Carolinas, an all-time winter high for Duke Energy Indiana, and a record for natural gas use in Duke Energy Florida and Duke Energy Indiana. The U.S. Energy Information Association reported that more natural gas was withdrawn from storage facilities around the country than at any other point in history.
The demand was similar to the 2014 Polar Vortex when temperatures shocked utilities across the country and particularly in the Southeast. In 2014, there was a shortage of natural gas, and temperatures were so much lower than usual that they caused some power plant equipment to freeze.
But, according to Sammy Roberts, Duke Energy director of system operations, thanks to planning and response based on the lessons learned in 2014, the company was able to meet demand this January with few equipment-related outages. Here are a few of the things that happen behind the thermostat to ensure that the heat stays on when temperatures drop.
Diverse fuel mix
Because electricity can’t be stored on a large scale, grid operators must match energy supply with energy demand at any moment. During extreme temperatures when demand is at its peak, every type of generation possible – nuclear, coal, hydro, renewables, natural gas – is running. Some sources, like nuclear, aren’t affected by the weather as much as others, like natural gas, which is not typically stored on-site and depends heavily on real-time availability.
Some natural gas plants are able to run on natural gas or oil, so when natural gas isn’t available or economical, operators have an alternate fuel available on-site. Before the coldest part of winter, teams prepare for high demand by filling fuel oil and coal inventories. When steep drops in temperatures approach, plant and grid operators and fuel managers from all of Duke Energy’s states coordinate daily to review plant availability, market conditions, fuel reserves, expected demand, etc. They then develop a plan that ensures reliability for the duration of the cold spell at the lowest cost possible.
Here are a few tips for managing your energy bill:
- Increase your home’s efficiency with these tips under $50.
- If you need assistance paying your bill, Duke Energy has a few options for customers who qualify.
If you do experience an outage, here's how you can report it:
- Text OUT to 57801 (standard text and data charges may apply).
- Report or view current outages online at duke-energy.com/winterstorm.
- Call the automated outage reporting system. Click here to see the number for your state.
Cold weather can be especially stressful on power plants for several reasons: most power plants rely on water for many processes making them susceptible to freezing in extremely cold temperatures. In addition to freezing, lubricants can thicken, fuels like oil that are stored in tanks for long periods of time can become sludgy, and running equipment at maximum capacity for extended stretches causes strain. During the 2014 Polar Vortex, these issues caused significant shortages in electricity. The North American Electric Reliability Corporation estimated that of the roughly 19,500 megawatts of power unavailable because of cold weather across the nation, more than 17,700 was because of frozen equipment. At the peak of the 2014 event, Duke Energy was able to meet an all-time high demand with voltage management processes and asking customers to conserve energy.
After that storm, utilities – particularly those in the Southeast -- developed a plan to avoid freezing. Now, as part of routine winter maintenance, operators are making sure that plants have the appropriate freeze protection, equipment and materials to manage the sub-freezing temperatures.
In recent years, Roberts said, winter-use records have become more common at Duke Energy. Energy-use records were most commonly set in summer, but with a combination of extended cold periods, inefficiency of strip heating and availability of space heaters, winter has taken the lead. Regardless of season, teams across Duke Energy are working together to make sure electricity is as reliable and affordable as possible.