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Duke Energy Learns From Drought: Increasing Water Efficiency in NC

Cowan's Ford Hydro Station created Lake Norman and generates electricity for Duke Energy.
Cowan’s Ford Hydro Station created Lake Norman and generates electricity for Duke Energy. (Photo via Duke Energy)

When you hear about a power outage, what causes spring to mind? Maybe a thunderstorm during the summer, possibly an ice storm in the winter months. In these cases damaged power lines likely prevented electricity from getting to your home. You may not have thought about how a lack of water could prevent your electricity from ever being generated.

Many don’t realize that water plays a vital role in generating electricity. On average, more water is used to generate your home’s electricity than you use to shower, flush the toilet, and do other daily tasks.

As the largest electric power holding company in the U.S., Duke Energy uses billions of gallons of water every year. Below, we’ll learn more about how Duke uses water and how it is working to conserve water in your state.


How much water does Duke Energy use every year?

According to Duke Energy spokesperson Randy Wheeless, Duke withdrew 6,250 billion gallons of water in 2015 and consumed 79 billion gallons of that.

Water withdrawn is water taken out of a reservoir. Most of this water, over 98%, is returned to the source. Water consumed is the amount of water removed and not returned due to evaporation. Water consumed decreased from 93 billion gallons in 2014.

What is this water used for?

Most of Duke’s water use comes from cooling its power plants. Duke’s thermal generation plants convert heat energy to electricity. Such systems generate heat during the electricity-making process and must be cooled to remain functional.

What is Duke doing that reduces the amount of water withdrawn?

Duke has recently retired many old coal power plants and replaced them with natural gas plants.

“When they do that, when they switch from these older coal plants to these newer natural gas plants, they are implicitly switching what type of cooling system they use,” says Dr. Jordan Kern, a research assistant professor at UNC who studies energy and water.

Most natural gas plants generate some of their electricity directly from force created by combustion, rather than relying entirely on steam processes like most coal plants. This means that natural gas plants have less need for cooling than coal plants.

Gas fired plants use about 50 percent less water for cooling than a similar coal plant, according to Wheeless. “As we retire coal plants and replace with natural gas, our overall consumption goes down,” Wheeless says.

Why is it important for Duke to be able to function with less water?

At 800,000 people and counting, Charlotte’s 8.4 percent growth rate poses a risk for Duke. With growing municipalities competing for water and demanding more energy, Duke needs to be able to generate electricity with less water available.

Though Duke’s cooling systems return most of the water to the basin, coal and nuclear plants could be at risk because they require so much withdrawn water. Duke has two major nuclear plants near Charlotte in the Catawba River basin.

“If you’re sucking up a lot of water through a straw and then returning 97% of it back downstream, you still have to have it there in the first place in order to operate the power plants,” says Kern.

Kern says that Duke, like many utilities, is increasingly susceptible to water shortages. “Part of that’s climate, part of that’s growth in that part of the state.”

As climate change continues, scientists expect more extreme weather patterns. This includes more severe droughts.

During the 2007 and 2008 drought, Duke had to make major changes to its energy mix. This included reducing hydroelectric generation by 67% at some points during the drought.

Kern says that the drought was a wake-up call for Duke and that since then the utility has improved on collaborating with municipalities to better manage water. “Compared to many water systems and utilities, I think that group has been pretty progressive in terms of accounting for climate change and uncertainty in the availability of water in the future,”he says.


Do Students Know Where Their Water Flows?

Living like the average American requires about 2,000 gallons of water a day. But what is all of that water used for? Five UNC students guessed at which parts of their lifestyles require the most water, then used National Geographic’s Water Footprint Calculator to find out. Check out their reactions below.



Katie Otto, a communications and women’s studies major at UNC, thought that she used the most water through her dishes being washed in the dining hall. She also guessed that showering and the manufacturing of her computer were at the top of the list.


Otto said that seeing her water footprint calculated was an eye-opener.  “I am very surprised that me as just one single person uses so much water,” she said.

Her water footprint for the food section was the most unexpected. “You know you’re using water when you’re showering but you don’t think that a lot of water goes into your dinner,” she said.



Przemyslaw Pudelko thought he used the most water showering and gardening.


Pudelko expressed surprise at how much the average water footprints were, especially in the meat and clothes categories. His footprint was highest in the transportation section, which he said was unexpected.

Pudelko suggested he could buy more local food to reduce the miles his meals travel. He also said he could take shorter showers and use more energy efficient appliances.



Teva Smith, a freshman biology major, thought that he used the most water when flushing the toilet and taking a shower. He also said he eats a lot of meat and knows that it takes a lot of water to produce animal products.


Smith noted that though he eats a lot of meat, he wasn’t very far above the average water footprint for that section. He usually only eats chicken, which has a lower water footprint than beef or pork.

Smith said he would consider down more on beef consumption since it’s unhealthy and worse for the environment. “I’ll keep up with the chicken, it’s healthy,” he said. “Healthy for me in that sense, not for the world.”

Though Smith said he wasn’t surprised by his diet’s water footprint, he said he didn’t realize how much energy he uses and how much water is used to generate it.

“I never thought that I used a lot of energy but I am always on my computer, phone, or technology so not too surprising,” he said



Dia Brown, a Spanish major at UNC, thought she used the most water while showering. She said needing to rinse out conditioner contributed to that water use.


Brown was most surprised by “Just how much, like the quantity of water that it takes for just one serving of food.”

She also said that the water footprint calculator helped her learn about ways to save water she was unaware of. “I didn’t know you could get a totally water efficient kitchen. I didn’t know that was an option,” she said.

She pointed out that such a project would probably be expensive and not available to many people. “So I don’t know how much of an option that would actually be. But that they exist is cool.”



“A lot of the foods that I eat require a lot of water,” said Emma Szczesiul, a UNC first year. “Meat takes a lot because you have to feed the animals.”

“And as Americans, our showers and toilets and other things use a lot more water than other places in the world,” she said.


Though Emma knew that it takes a lot of water to produce meat, she was still surprised by that section of her water footprint. She was impressed by how much diet water footprint decreases with a vegetarian or vegan diet.

She was also surprised that driving her energy efficient car still had such a large effect on her water footprint. “I drive a Honda Civic and I was expecting that to make a difference, but it still uses a lot.”

How Much Energy Is In Your Drink?

Move over, Red Bull. There’s a new energy drink in town.

When you think about how your city uses energy, transportation, lighting, and air conditioning probably come to mind.

But according to the EPA, water utilities are usually the largest energy users in a municipality, often using 30-40% of the municipality’s total energy consumed. Here in Orange County, the Orange Water and Sewer Authority (OWASA) works to lower that number through efficiency projects.

Let’s take a look at how energy was used to bring you your last glass of water and check out ways OWASA works to use that energy more efficiently.

Reservoir To Tap

Step One

The utility first pumps raw water from a reservoir to a water treatment plant. OWASA’s treatment plant is on Jones Ferry Road, less than two miles from UNC’s campus.

OWASA recently changed their pumping strategy at the reservoirs according to Mary Tiger, OWASA’s sustainability manager. This allows the utility to better match water need to water removed and avoid extracting excess.

Step Two

Next the water is pumped from tank to tank while being cleaned and processed.

Step Three

Once the water is clean, the utility pumps water out into the distribution system at high pressure.

Why is having high pressure so important? “To ensure clean drinking water, we want to make sure that there’s pressure in that distribution system so that if anything happens with the pipe the water’s coming out and nothing is coming in,” says Tiger.

Some water is pumped directly to homes and some is pumped up into elevated storage tanks, also known as water towers. The towers then use gravity to give the water the pressure it needs to move through distribution lines and fill your water glass.

“We are able to utilize the tanks to pump at off-peak times,” says Tiger. This means OWASA lets water down from towers during the day when energy demand is high. Then they pump water up into the towers at night when fewer people need energy.

If you thought that sounded like a lot of pumping, you’d be correct. “For water treatment the energy use goes back to pumps moving water around,” says Tiger. Finished water pumping accounts for 70% of energy use at the Jones Ferry Road plant.

Wastewater Treatment

It’s a few hours after that glass of water and your waste leaves your home and makes its way to OWASA’s Mason Farm wastewater treatment plant. We’ll look at the top three energy-using processes that help make your wastewater safe.

Number One

At the Mason Farm wastewater treatment plant, the aeration requires the largest percentage of energy. During aeration, air is added to the wastewater while microorganisms consume waste particles. According to OWASA, this aeration is the most important step of the cleaning process. It also requires the most energy, accounting for 27.6% of energy use at OWASA’s Mason Farm wastewater treatment plant.


Processing waste solids removed during wastewater treatment takes 25.6% of energy used at the plant. Once treated, waste solids can be used as fertilizers.

Second Runner-Up

Pumping water requires a lot of energy during wastewater treatment as well, accounting for 15.7% of energy consumed.

Improving the System

Now once treated wastewater, known as reclaimed water, leaves the plant, UNC uses some of it for irrigation, cooling, and flushing toilets. The university funded OWASA’s reclaimed water system, finished in 2009, and now uses reclaimed water for 27% of its water needs. OWASA estimates that it takes 35% less energy to use reclaimed water than potable drinking water.

OWASA also recently finished a renovation of the Mason Farm wastewater treatment plant that has led to a 30-35% reduction in energy use, according to Tiger.

Energy Efficiency Financing Options in North Carolina

A home energy efficiency project can help reduce energy use, on average, by 12 to 17 percent. And this translates to a lower electricity bill.

Your options for financing such a project in North Carolina currently depend on your electricity provider. Let’s explore some of your energy efficiency financing options here in North Carolina.

Using Personal Credit

To fund an energy efficiency project for your home in most places in North Carolina, you would take out a personal consumer loan. This is a loan issued without collateral. The bank simply extends credit and you repay it on a fixed schedule.

A personal consumer loan can vary in how many years you have to repay it, the interest rate and the amount. All of these variables are based on your ability to repay the loan.

Melissa Malkin-Weber, Sustainability Director at Self-Help Credit Union, explained how this works.

“A bank would look at somebody’s credit score, usually a FICO score, and go ‘based on this FICO score does that indicate that they’re a good risk or not’,” Weber said.

Personal consumer loans are available at almost any bank, but pose problems when used for energy efficiency projects.

“The deal with energy efficiency is that you want to stretch out your loan-repayment as long as possible,” she said. “But that personal loans tend to be around 5 to 7 years, so there’s a mismatch.”

In addition, consumers with low credit scores who could benefit from energy efficiency projects usually cannot qualify for this type of loan. The Department of Energy does offer home weatherization programs that can increase efficiency for very low-income people, but many people do not qualify for either of these options.

On-Bill Tariff

The Roanoke Electric Cooperative, based in Aulander, NC, an example of an electricity company that allows ratepayers to fund home energy efficiency projects through an on-bill tariff. This is a type of on-bill financing method. With this method, loan repayment is tied to the electricity meter, not an individual.

The loan’s association with the meter means that lenders look at the bill-payment history of that meter rather than personal credit. This opens up energy efficiency project financing to those who pay their electricity bill on time but have poor credit.

Tying the loan to the meter also allows people who may move in the near future to improve their home’s efficiency. The on-bill tariff payment stays with the resident benefitting from increased efficiency rather than following the person who initiated the loan.

This method forces the utility to assume the risk of default, or to potentially lose money when the resident cannot repay the loan. However, this is not as large of a risk with energy efficiency loans as with other loan types.

“Default rates on loans for energy efficiency are much lower than the default rates for other types of loans,” Carol Rosenfeld, senior finance analyst at UNC’s Environmental Finance Center, said.

In fact, default rates on energy efficiency rates are between zero and three percent.

Jennifer Weiss, energy efficiency policy manager at the Southern Alliance for Clean Energy, warned it will take time to tell more definitively how safe of an investment efficiency loans are for banks and utilities.

“Default rates have been really low in what we’ve seen so far with the on-bill programs,” Weiss said. “But it’s still new.”

The on-bill tariff is currently only offered in a few areas in North Carolina serviced by smaller electricity providers. Most North Carolina electricity consumers need to use personal credit for home energy efficiency projects.

Weiss brought up the possibility that Duke Energy might offer an on-bill financing program such as the on-bill tariff in the future. She said that the Southern Alliance for Clean Energy is working with Duke on an on-bill finance proposal.

She clarified that work with Duke on on-bill financing is really in preliminary stages.


Carolina Students Consider Closeby Wind Turbines

Most people would support something that could keep air cleaner, improve rural economies, and reduce dependence on foreign oil. Wind turbines can do all three, but often run into roadblocks because of complaints that they are ugly. Many citizens support the technology in theory but don’t want wind turbines to mar local landscapes. I asked five UNC students how they would feel about being able to see a wind turbine from their bedroom windows.

Energy Deregulation in North Carolina

Energy Deregulation in North Carolina


Today in the United States, sixteen states have deregulated electricity and twenty-two have deregulated natural gas. This map by Quantum Gas shows deregulation by state. As states continue to vote to enact or repeal deregulation, it remains a controversial issue nationwide.


Why was energy regulated in the first place?

In a regulated electricity market, only the utility can sell electricity directly to the consumer. Consumers who want to buy electricity can only buy from the local utility. There is no competitive pricing because a regulatory body sets the electricity rates.

Energy regulation began soon after electricity and gas started becoming available to consumers. The necessary infrastructure to create and transport energy was not well formed yet. Lots of companies building small pieces of infrastructure meant that electricity service was spotty and unreliable.

The government granted utilities monopolies in their areas in response to these coverage issues. The catch? The utilities were legally obligated to provide energy to all consumers at all times.

Now that the transmission infrastructure exists, some states are voting to deregulate their electricity markets.


What is a deregulated electricity market?

In a deregulated electricity market, approved providers can sell energy to consumers. These approved providers are called Retail Electricity Providers, or REPs. Consumers can choose from which REP they buy electricity.

There is no set price for electricity, so in theory a deregulated system functions as a free market. Deregulation allows competition between energy suppliers, but keeps the utility’s transmission and delivery infrastructure. Though the local utility does not have guaranteed returns, it is still responsible for maintaining that infrastructure.


What’s going on with deregulation in North Carolina?

North Carolina has not deregulated electricity or gas and deregulation in the immediate future seems unlikely. The North Carolina legislature has not been receptive to recent proposals to allow non-utility companies to sell energy.

Last year the legislature voted down House Bill 245, the Energy Freedom Act. The bill would have allowed companies to install solar panels on homes and sell the electricity directly to the residents.

North Carolina has debt from building expensive nuclear plants, which could prove problematic for deregulation legislation. Michael Walden, an NC State researcher, says that debt would make electricity rates initially rise under deregulation.

Walden also predicts that energy prices would later fall by 15 to 20%. However, paying off the debt in a free market would put Duke Energy at a disadvantage. Debt issues aside, existing monopolies like Duke are likely to use their political power to keep the regulated system and their monopolies.


So which one is better for me?

Ah, this is where it gets tricky. Proponents of deregulation maintain that the resulting competition will drive down prices. They also argue that deregulation will pave the way for increased renewable energy use.

Those against deregulation cite a lack of responsibility for long-term energy projects. Since no company is legally accountable for providing electricity, they are likely to operate with short-term gains in mind. Additionally, companies want to make the most profit possible and may focus on more lucrative big electricity users.

So your opinion might depend on how well you think the free market works for smaller energy consumers. Competition could potentially bring your electricity prices down and increase use of renewables. But with no responsibility for providing energy, companies could also focus on the more profitable large customers instead of average consumers.



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  • “How Electric Choice Works,” AEP Energy, 2016
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  • “AEP, Sierra Club Back Profit-Plan Guarantee,” The Columbus Dispatch, 2016
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