Southern Company is one of the largest producers of electricity in the United States, with 42,000 megawatts (MW) of generating capacity. It has 9 million customers and businesses nationwide, with electric utilities in three states and natural gas distribution utilities in four. Approximately 2,800 MW of Southern Company’s power is generated by hydropower, making it one of the top hydropower producers in the nation. Over the next 10–15 years, Southern Company will be carrying out a complete overhaul of its 29 hydropower facilities. In this interview, we speak with Herbie Johnson, Southern Company’s hydro general manager, about how Southern Company is planning and carrying out this vital work. 

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Hydro Leader: Please tell us about your background and how you came to be in your current position. 

Herbie Johnson: I spent 6 years in the military, then used the GI Bill to attend Auburn University, where I obtained a bachelor of science in civil engineering. I interviewed with the Alabama Power Company and started working in hydropower right out of college in 1994. My first job was as a hydrologist, and I worked in the plants and helped support upgrades. I worked my way up to be the general manager of all the Southern Company hydro facilities. 

Hydro Leader: Please tell us about Southern Company. 

Herbie Johnson: Southern Company has three regulated utilities: Mississippi Power Company, Alabama Power Company, and Georgia Power Company. We also have a natural gas company and a competitive wholesale firm called Southern Power. We currently serve 9 million customers through these subcompanies. We also supply transmission and distribution, fiber optics, and network communication services. Our brand is focused on excellent customer service, high reliability, and affordable prices. For more than a century, we’ve been in business building the energy future. 

Hydro Leader: What role does hydropower play in Southern Company’s overall operations? 

Herbie Johnson: The company originally started with hydro, so our hydro operations have been around for 100 years. Today, we rely on hydro more than ever. It’s part of our plan to make our operations net zero carbon by 2050. It adds flexibility to how we can bring renewable energy sources into our market. Hydropower can be used to store and dispatch energy, so it saves our customers money on fuel costs. The Georgia and Alabama Power Companies have 2,800 MW of hydro generation across 102 units at 29 dams. The 2,800 MW of hydro generation makes up 5–7 percent of Southern Company’s total generation mix— the percentage varies depending on how much rainfall we get in a year. 

Hydro Leader: When did Southern Company realize that it needed to undertake a major rehabilitation of its hydropower infrastructure, and how did that planning get started? 

Unit 2 at Southern Company’s Terrora Dam, located near Lakemont, Georgia, was modernized in 2020.

Herbie Johnson: Several of our hydropower plants are over 100 years old. They were built well and have stood the test of time. Many others are 60–80 years old and are at the end of their design life. Components have worn out, the balance of plant equipment has worn out, and electronics and technology have to be modernized to keep up with changes in technology. We must maintain the structural integrity of the dams and spillway gates and ensure that they are adapting and will stand up to the elements for the long term. That’s part of our scope as well. Southern Company has always invested in hydro facilities when they hit the end of life, and simply because of the age of our fleet, a big wave of units is reaching the end of life all at one time. 

I already mentioned the services hydro facilities provide to our grid and their flexibility. But there’s another aspect of hydro that is important to us at Southern Company. A hundred years ago, where these hydro plants were built, they were out in the middle of nowhere. You had to build a village to support their construction. Over the last 100 years, what were once poor communities have become prosperous communities anchored by the reservoirs behind our dams. The houses, businesses, and recreational opportunities around our lakes draw people in. They spend money, it adds to the tax base, and that helps create better schools, hospitals, and roads. Reinvestment in hydro doesn’t just help us keep making energy and help keep these units generating for our customers, it also helps preserve the wonderful communities around our lakes and reservoirs. We need these communities to have confidence that we see our hydro facilities as forever assets. 

Hydro Leader: What does the rehab effort entail, and where are you in the process? 

Herbie Johnson: We’re just getting started with our 10‑year plan. Our plan remains flexible in the sense that we are spending capital dollars when appropriate and approved, so it could end up taking up to 15 years total. Overall, we expect more than $3 billion to go into Southern Company’s hydro fleet. We expect more than 70 new turbines to go into our plants. We expect more than 50 generators to be rewound. We will also be rehabilitating and replacing spillway gates, header gates, stop logs, balance of plant equipment, switch gears, transformers, and control systems. It’s a total reinvestment in these plants. Our goal is to have them running reliably for the next 80 years. 

So far, we have completed the modernization of two units: Lay unit 5 and Terrora unit 2 were completed in 2020. However, we have been planning for longer. We started thinking about the vendors we were going to use 10 years ago, recognizing that no one vendor can do all this work and that certain units would require specialized vendors. We started finding quality vendors and figuring out who would be the best to support certain types of work. 

Hydro Leader: What are the biggest challenges of a rehab effort like this? 

Herbie Johnson: The majority of the time it is not possible to disassemble one of our hydro units to inspect it prior to going out to bid the work. With that in mind, the biggest challenges are the unknown, discoverable items that you find as you carry out the total rehab of a unit. In some cases, you don’t have drawings of the unit at all. A lot of them are lost. Some of the plants have been there for 100 years, and we don’t have knowledge of what to expect on the inside because we’ve never taken the unit apart. A lot of the time, the first time you see the major components involved in the upgrade is during the disassembly. That’s when you find things that you didn’t expect. We’re good at creating flexibility in our contracting, schedules, and budgets to account for those unknowns and discoverable items. 

Hydro Leader: What kind of outage planning are you doing for this? 

Herbie Johnson: The majority of our plants have multiple units, but due to the fleet’s age and the way the units were designed, we can only work on one unit in a plant at a time. It’s important that we determine which unit is most at risk and in the worst shape, start with that, and then continue to the others. The scheduling of that is important. At different times of the year, plants and units must be operating to meet environmental and recreational needs. We’ve got to meet Federal Energy Regulatory Commission (FERC) guidelines. In some locations, we’ve got to manage flood control. All those aspects go into how we schedule and plan outages. Most of these outages last 10–12 months, starting from the time when we take a unit apart to the time we get our new components and take it through startup. 

From a fleet standpoint, as we get further into our modernization effort, we’re going to have a lot of work going on. We’re going to have multiple hydro vendors and craft workers at multiple plants. There will also be significant project management and supply chain tracking budgets. As that starts to stack up, it’s going to be quite a lot of work. If you don’t have everything planned in detail up front, you’ll get really overwhelmed. We feel that we have a great plan and that we have balanced all those priorities. We believe that we’re addressing the units with the highest risk first. We know how many people and the type of people we’re going to need and when we’re going to need their support. 

Hydro Leader: What kind of public outreach efforts have you done to prepare for this effort? 

Unit 2 at Southern Company’s Terrora Dam, located near Lakemont, Georgia, was modernized in 2020.

Herbie Johnson: Our regulated utilities in both Georgia and Alabama are regulated by the public service commission. Maintaining your business cases, communicating with your public service commission, and having timely and accurate information is critical to the outreach. It’s something we vow to do, and I think we do it well at Southern Company. From a customer standpoint, we partner with the land organizations that help manage our reservoirs and recreational opportunities. Quite often, outages or reservoir drawdowns, which may be necessary to support certain kinds of work, affect recreational events. That’s where you really have to make use of your public relations group and make sure that the customers understand the reasons for the interference and how long it will last. We communicate using a variety of media, including Instagram, Facebook, the normal distribution list in our local newspapers, and an app called SmartLakes. 

Hydro Leader: What economic effect will the rehab effort have on the areas where your hydro facilities are located? 

Herbie Johnson: We have made a focused effort to maximize the use of local suppliers, consultants, and contractors. We also make a strong effort to patronize diverse suppliers and small business owners. We try to bring as many of the small and diverse suppliers into these work efforts as we can. The majority of those are local, which means that there is a direct positive economic effect on our communities. When we need to send parts off for rehabilitation, we try to find shops in our local communities. If there’s an area where we can positively affect a community that needs it, we always try to give it priority and work with it. These are longer-duration jobs, and that can provide great benefit to these communities. This total plan will take 10–15 years, so there will be workers staying in the local hotels and eating at the local restaurants. That is also true of people who work for the suppliers and the transportation support, who also tend to be local. 

Hydro Leader: What is your message to the federal government? 

Herbie Johnson: I’ll speak directly to FERC, which governs the licensing process for our hydro plants. FERC recently made a move to a 40‑year license. I would like to thank FERC for that. It gives us some assurance that as we’re making these investments, we can make plans about how we’re going to run the units and what specifications we should build into our process. I think FERC made an excellent decision there. It has got an excellent template for licensing renewals. My message to FERC is to stay the course, keep the process efficient, and hold stakeholders accountable for timeliness and participation on the front end. 

I would also encourage FERC to support pumped storage facilities, especially closed-loop pumped storage, and to help keep the licensing and construction process efficient. 

Hydro Leader: Is there anything you would like to add? 

Herbie Johnson: We’re doing some great things in our effort to become carbon net zero by 2050. We have closed and converted a lot of coal plants and have added a lot of renewable energy. We are building two new nuclear units right now, the first in the United States in three decades; they’re getting close to their startup. As I mentioned earlier, hydro’s flexibility makes it as valuable today as it was 100 years ago, if not more so. In fact, all the stuff we’re doing right now really plays to hydro’s favor, especially in the area of pumped storage. Since the 1970s, Southern Company has been looking at local land features that could support additional pumped storage hydro. We designed and built Wallace Dam and the Rocky Mountain pumped storage facility. We brought Rocky Mountain online in the early 1980s and then sold majority ownership to Oglethorpe Power; now, we’re only a part owner. As we invest more and rely more on solar and wind and need more energy storage facilities, I think Southern Company is going to continue to keep pumped storage hydro in mind as a key part of the potential equation. Here at Southern Company, we use the phrase “Keep all arrows in the quiver,” and pumped storage hydro as a large-scale storage option is something we’re going to continue to look at. I think there are over 50 preliminary licenses for pumped storage hydro in the U.S. market right now. There’s a lot of opportunity there. 

Hydro Leader: What is your vision for the future? 

Herbie Johnson: I used the term forever asset, and that sums up my key vision. I want the new employees we’re hiring to support these plants to know, whether their job is in dam safety, operations at the plant level, or reservoir operations, that they’re walking into a plant that’s going to be modern and built with their safety in mind. It’s going to be built to have minimal maintenance requirements. I want them to have the confidence that they’re entering an area of work that’s going to be around for them for the long term and that will hopefully support their healthy and well-earned retirements. I want to project that same confidence to our communities. We need people to continue to buy houses around the lakes, to buy boats to fish in the lakes, and to enjoy the recreational opportunities. All of that adds to these communities. I want them to hear from us that these are forever assets and that that is reflected in how we’re treating them and the quality of work we put into them. 

Herbie Johnson is the general manager of hydro at Southern Company. He can be contacted at