The U.S. Army Corps of Engineers has many crucial roles: It maintains the nation’s navigable waterways, it works to reduce flood risk, it engages in civil engineering projects both at home and abroad, and it helps rebuild war-torn areas. Less known to many is that the Army Corps is also the largest single owner-operator of hydropower and clean energy plants in the United States, with 75 hydropower stations. The entity in charge of maintaining the engineering and design of this hydropower fleet is the Hydroelectric Design Center (HDC) in Portland, Oregon, the professionals of which provide hydropower planning, engineering, and design services and also serve as the “Maytag repairmen and women” of the Army Corps. In this interview, HDC Deputy Director John Etzel tells Hydro Leader about the Army Corps’ role in supporting the national energy grid and how the HDC helps enable it. 

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

John Etzel: I have a bachelor’s degree in civil engineering from Oregon State University and a master’s in public administration from the University of Colorado. I worked in private industry for about a year before beginning to work for the Army Corps in 1986. My first position at the Army Corps was as a structural engineer in Portland, Oregon. I have also held other positions within the Army Corps, including technical lead and project manager. In 2004, I started working for the HDC in Portland as its first project management branch chief. In 2010, I was selected to serve as the deputy director of the HDC, the role I currently hold. I work with a team of 170 professionals who support the hydropower planning, engineering, and design for the Army Corps’ 75 hydro power plants across the nation. I’ve been humbled to serve such amazing professionals in my 34 years of public service, tackling some of the nation’s toughest water resource challenges. 

Hydro Leader: Would you give a general introduction to the history of the Army Corps and its relation to the rest of the Army? 

John Etzel: The Army Corps’ history dates back to 1775, when General George Washington needed engineering support to design and construct military fortifications. The Army Corps’ fortifications were instrumental in defending the new nation. I think the Army Corps’ best-known modern-day legacy is the civil works mission we carry out on the nation’s rivers. Rivers were identified as a strategic highway of our new nation from both a military and a commercial perspective, and the Army Corps was commissioned to keep the nation’s waterways free from snags and sandbars. 

As the dam-building era began in the early 1900s with the dream of harnessing hydropower, Congress asked the Army Corps to maintain the balance of damming up the nation’s waterways while assuring that they remained navigable. The Army Corps was put in charge of providing approval to individuals who wanted to dam rivers. The Army Corps also designed and built two small hydropower plants in the early 1900s on the Mississippi and Tennessee Rivers. 

Under the New Deal, President Franklin Roosevelt charged the Army Corps with developing three large federal hydropower projects with the goal of providing consumers with low-cost energy. This is the beginning of the era when the Army Corps began to include hydropower as one of the missions of our many multiple-use water projects, along with things like navigation, flood risk management, recreation, and water supply. 

Hydro Leader: Does the Army Corps fall under the normal command structure of the Army? 

John Etzel: Right now, the Army Corps has 34,000 employees worldwide; less than 1,000 of them are army officers. The vast majority of the team is made up of civilians. The Army Corps is led by a chief of engineers, Lieutenant General Scott Spellmon, who works out of our headquarters in Washington, DC. There are also 9 division offices and 44 district offices located throughout the United States. These offices and their missions are led by military officers and senior civilians under the general Army command structure. 

Our chief of engineers works directly with the Pentagon on the military side for military missions. We also have civil works missions, in which we work with the assistant secretaries of the Army and civil works. We serve at the direction of the administration. Of course, we need appropriations, and those appropriations come from Congress. We don’t work on anything on our own accord. We are essentially directed by the executive branch and funded by Congress. 

An exception to the congressional funding piece, particularly in the hydropower world, is the use of customer funding. Recently, customers have provided funding directly to the Army Corps for use in capital hydropower improvements. 

Hydro Leader: Do civil works projects make up the majority of the Army Corps’ activities today? 

John Etzel: In my world, yes, but there are large military missions that the Army Corps participates in that are related to defense. We build defense facilities like barracks and air bases, for instance, both domestically and abroad. 

Hydro Leader: Is there anything else you wanted to add about its size and the scope of the Army Corps’ work? 

John Etzel: The Army Corps is the steward of the nation’s water resources. Water particles know no boundaries, including state boundaries, so Army Corps missions are most often attached to water on the civil works side of the spectrum. Our nation’s waterways serve multiple purposes, and the Corps is charged with facilitating all those purposes, including flood risk management, navigation, environmental stewardship, irrigation, drinking water, recreation, and hydropower. 

Within the Army Corps, subject-matter experts and their teams in each of these business lines come together to collectively develop holistic solutions. We are, of course, the Army’s engineers, which means we also provide military design support and aid in the nation’s toughest natural disaster and recovery missions and engineering challenges. Most recently, we were asked by the Federal Emergency Management Agency to support it by building hospitals for the COVID‑19 pandemic. We worked to do that in short order by converting other buildings to hospitals. 

Hydro Leader: How many dams does the Army Corps operate and maintain, and where are most of those located? 

John Etzel: The Army Corps owns, operates, and maintains approximately 700 dams across the nation. Seventy-five of those facilities include powerhouses that operate a total of 376 power units. Roughly speaking, about one-third of our 75 hydropower plants are located in the Northwest, and two-thirds are located in the Southeast. Since the Northwest plants are the larger plants, that one-third of our plants represents roughly two-thirds of the Army Corps’ generation capacity. The remaining two-thirds of the plants in the Southeast represent one-third of the capacity. The Army Corps’ plants produce over 21,000 megawatts of energy a year, which is enough to supply 5.4 million homes with clean, zero-carbon, renewable energy, making the Army Corps the largest single owner-operator of hydropower and clean energy plants in the United States. 

Hydro Leader: Tell us about the HDC. 

John Etzel: The HDC is the Army Corps’ hydropower mandatory center of expertise. It is made up of 170 professionals whose work consists of performing hydropower planning, engineering, and design on a day-to-day basis. The vast majority of the HDC’s staff are located in Portland, Oregon, but we have a handful of employees stationed in other parts of the country, including in Mobile, Alabama, and Washington, DC. As I mentioned, we provide services across the United States. We also provide hydropower engineering services to other agencies, including the U.S. Department of Energy and the Bureau of Reclamation. We have also supported hydropower engineering needs outside the United States, including in places like Iraq and Afghanistan. 

Hydro Leader: Would you tell us about how the HDC supports the national grid? 

John Etzel: Our role in supporting the national grid relates to the grid’s generation supply. The HDC’s focus is limited to hydropower planning, engineering, and design services. The Army Corps’ local operations departments operate and maintain its hydropower plants. Power marketing administrations (PMAs) and local utilities market and transmit the power to the customers. The Army Corps’ role in supporting the national grid is to operate and maintain its generating assets to assure the highest level of reliability and stability and to ensure that it can deliver power on demand. Many of our systems are equipped with automated generation control, which automatically ramps up or down power generation to meet real-time power demand. 

Hydro Leader: Would you tell us about the HDC’s role in rapid response to failures and mechanical issues at the various Army Corps dams and hydroelectric facilities? 

John Etzel: I like to say that the HDC are the Maytag repairman and women of the Army Corps’ hydropower fleet. The HDC is on call 24 hours a day, 7 days a week, to immediately assist our project operators to identify what is causing a problem and what the solutions are. In many cases, we can troubleshoot the problems virtually with our subject-matter experts on generators and turbines and controls. In other cases, the HDC deploys a field crew for on-site troubleshooting, forensic testing, and resolution of the problem. 

Hydro Leader: Does the HDC respond only to issues at Army Corps–owned facilities? Are you ever tasked with giving aid to non–Army Corps facilities? 

John Etzel: As I mentioned earlier, our primary funding today comes through direct customer funding tied directly to specific projects. We do work for other agencies— Reclamation, for example—including the design of controls and monitoring for operation at Grand Coulee Dam. We also support the reconstruction of war-damaged facilities in countries like Iraq and Afghanistan. We are open to support other agencies and other causes. 

Hydro Leader: Would you tell us about hydropower’s role in supporting other renewable energy resources? 

John Etzel: I believe that one of the world’s best-kept secrets is hydropower’s role supporting and enabling other renewable energy resources in their ability to supply the power grid. Hydropower is reliable and predictable. It can pick up and drop off power generation instantaneously as necessary to meet both supply and demand. Our team of subject-matter experts design automated generation controls that provide the right voltage and frequency to consumers 24/7. With a predictable power source, namely flowing water, hydropower can immediately accommodate the unpredictable start and stop times of less-predictable renewable resources, including wind and solar power, and thus maintain a constant power source for the grid. 

Hydro Leader: Is the role of hydropower changing as the prices of energy from other renewable sources fall? 

John Etzel: Hydropower provides not only power, but also critical ancillary services for regional grid stability. What this means in layman’s terms is that it’s not enough to provide an electrical current that must be coming to the end user at 240 volts and 60 hertz on demand. Hydropower generating equipment provides proper power spinning reserves and adjustments to power output to ensure that consumers won’t receive too much power coming into their households, which would burn up their electrical equipment, but enough power to keep things like clocks running at just the right speed to accurately tell the time. It’s not enough to be the cheapest power source on the block. Other energy sources, such as wind and solar, cannot provide the constant power output that consumers need on their own. 

Hydro Leader: How do you see the Army Corps’ role in hydropower changing in coming years? 

John Etzel: There’s a lot of interest in doing things better at a lower cost. One item we’re working on with the PMAs is setting our equipment up to enter the Energy Imbalance Markets. This step would allow energy balancing authorities to expand outside of constrained local markets to provide stabilized power to larger regional markets. This change would allow for greater opportunities to balance power from regions that have a surplus of energy to those that are in need. That’s a new and powerful thing in the hydropower world. More project remoting—that is, the virtual operation of our powerhouses from a central location—is also something that may allow us to be more efficient as an agency. 

Hydro Leader: What is your vision for the future? 

John Etzel: Many people think of hydro power as an old technology. In some ways, it is. However, I think of hydropower as the future of energy. It’s an exciting time to be working in hydropower. We’re moving from old, mechanical, analog systems to new, digital, reliable ones. Equipment efficiency continues to squeeze out more megawatts from the same amount of water with each generation of design. We are focused on mitigating environmental impacts in rivers, designing more fish-friendly turbines to improve juvenile fish survival, and removing oils where we are able to. The HDC will continue in its quest to be a leader in hydropower and engineering and to be a steward of the nation’s water resources. 

John Etzel is the deputy director of the U.S. Army Corps of Engineers’ Hydropower Design Center. He can be contacted by e-mail at