From Scott Carlberg

Is everyone dried out from the heavy storms last week in the Carolinas? While you may have been hunkered down during the storms, power companies with hydro-electric plants were hard at work during and after those storms. They have to be fast and flexible during unusual rain events.

Meteorologist Brad Panovich

Last week’s weather was unusual, too, says Brand Panovich, Chief Meteorologist at WCNC-TV in Charlotte: ““The pattern over the past 2 weeks has been very un-summer-like. We typically don’t have this type of jetstream and upper-level pattern. You combine what would be typical jetstream for Spring or early Autumn with the really hot and humid airmass of summer and the storms were very efficient rain producers. So we ended up with not only some severe weather but slow-moving heavy rainfall producing storms day after day. The problem was you just didn’t know day to day where those storms would set up.”

Don Ligon, Duke Energy

Why does that matter to electric companies? They routinely have to manage lake levels and assess the electricity they can produce. Everyday. So, when there is an unusual rain event, they have to be especially vigilant about where rain is heavy and how it can affect lakes and their users and neighbors, and how the rain flows down stream.

Radar around Charlotte – August 2, 2018. Lots of rain to chase

“We were chasing raindrops a lot last week,” said Don Ligon, Manager Regulated Renewables Operations Center for Duke Energy. That’s a good way to put it, too, since they have to track the rain. “When there is an event with heavy rain in one lake area, it impacts the whole system.”

Duke manages more than 200 miles of rivers and lakes on the Catawba River system. These 13 hydro stations, spanning nine counties in N.C. and five in S.C., provide power and recreation along the entire river system.  That’s 11 lakes and 13 hydro stations on the Catawba system, from Lake James to Lake Wateree. 

One of the lakes and dams managed by Duke Energy

“Regardless of the electric demand, water has to move through the water shed,” says Rick Miller, a hydroelectric engineer with HDR Engineering, which has a major Charlotte base. “Water has to be managed on its way downstream, paying attention to the capacity of the hydro plants, how many days the water takes to travel, and what other rain might be expected.”

More than just electricity and recreation, Miller says our hydro facilities do something else for consumers. “Hydropower provides flexibility to the grid. It is the shock absorber for the grid; goes on-and-off fast to meet changing energy needs during the day. That is a big engineering benefit. The Carolinas are in a fortunate situation to have the hydro facilities they have.”

Our power companies may continue to get tested. The Associated Press said on August 2: “Rainfall records were set from the mountains to the coast in July, and the National Weather Service suggests August will bring more of the same.”

From Energy Consumers for the Carolinas, all this is to say that when you look up and see that it is raining, there are people with their heads down and hard at work to make sure that rain is managed well for our energy system.

Here are a few good references for hydropower:

National Geographic: Hydropower. Published almost ten years ago, but still a great overview.

U.S. Geological Survey: Hydroeletcric Power and Water.

Alternative Energy: Hydroelectric Power.

National Hydropower Association: Types of Hydropower

A portion of my personal front yard lake system following the rain