Oak Ridge National Lab Focuses on Modular Hydropower Designs, Material Sciences

Scott DeNeale, a Water Resources Engineer at Oak Ridge National Laboratory, spoke with Turbomachinery International about the lab’s current research projects in hydropower and how there’s been a shift toward retrofitting dams and modular designs: The era of building large new dams is largely over. The focus is now on improving existing infrastructure with modular, low-head hydropower solutions that can be more easily integrated and deployed. The lab is also exploring the use of metal additive manufacturing to create standardized and efficient Francis turbines, potentially reducing costs and lead times compared to traditional custom-built turbines.

TURBO: Can you tell us a little about Oak Ridge National Lab?

DeNeale: Oak Ridge National Laboratory is the largest multi-program science and technology laboratory in the United States. It's managed by UT Battelle but is owned by the U.S. Department of Energy (DOE). As part of my research, I do a lot of work for hydropower. The research and development that I do touch on a lot of different things. We look at grid integration, markets, reliability, performance, hydrology and hydraulics, water management, biodiversity and ecosystem science. We look at technological advancement as well.

TURBO: What recent advancements have you seen in turbomachinery used in hydropower technology and pumped storage hydropower technology?

DeNeale: Conventional hydropower—what we would speak to is the age of the big dams is over, so a lot of what we're looking at is retrofitting existing dams, replacing units, or adding new units to existing dams. And there's an area looking at canals and conduits as well. So, some of the advancements I've seen are geared toward the existing infrastructure, which has largely low-head or low-pressure potential. It’s a slightly different design used to capture that design point. Another area is modular technologies and standard technologies. Conventionally, many turbines are custom-built, so the ability to have a standard design that could be plug-and-play has been of interest. We've had some research related to that over the past 10 years, working with industry on advancing their concepts as well.

For pumped storage … I would refer you to a report from some of my friends at Argonne National Laboratory. They have done some great documentation of innovations—a lot of it's conceptual for pumped storage but some cool innovations there. However, there has been no new pumped storage since 2012. And, even with that, that was a very small project. So, since the mid-nineties, there really hasn’t been much of anything in terms of new pumped storage, but there is a great demand for it.

Credit: Adobe Stock

TURBO: You mentioned two technological advancements: modular technology and low head. Can you elaborate on those and any industry trends you’re seeing overall?

DeNeale: A lot of existing and older hydropower plants used higher head technology. Low head is a different type of turbine—a bulb or Kaplan design works better for those low heads than a Francis or Pelton turbine. Those are relatively established technologies, but getting below 20 feet of head is a challenge, so a lot of smaller companies are trying to innovate in that space.

From the modular standpoint, the idea is to capitalize on the existing infrastructure. There are over 90,000 dams in the United States that are documented, and only 3% of those are hydropower dams, so there's an incredible number of existing dams that could be tapped for hydro. All may not be suitable, but we've seen thousands that really could be easily tapped; many are even at federal facilities. Some damn designs are standard where even a single design could plug in with the existing water conveyances—pipes or spillways or different water conveyances that could be tapped to convey that water through a turbine. As such, modular designs are of interest.

We’ve worked with four different companies on our standard modular hydropower project to advance modular concepts. Of those, two were related to fish passage, and one was related to sediment passage. Natel Energy is focused on fish-friendly technology for generating hydropower, for example. It’s called the FishSafe Hydropower Turbine, and the idea is they can pass fish through a high-speed, high-rotation turbomachine without mortality and safely pass the fish through 98 - 100% of the time. It’s a game changer in the industry and an exciting opportunity to work with them.

TURBO: What are you most excited about in this space?

DeNeale: Hydropower has been around for roughly 150 years, so it’s an old industry. The preconception is that it's mature and we already know everything, but that's not true. There are a lot of opportunities to complement new generation with environmental compatibility to make sure we’re sustainably doing things. It’s exciting watching the next generation of the workforce. I've worked with students, teachers, and interns here at the lab, and it's cool to see them learn about hydropower for the first time. This is an engineering discipline that sits in between two really important resources: water and electricity. Both of those are essential to civilization as a whole and advanced societies. Just working at Oak Ridge National Lab, we have somewhere around 7,000 employees with wide-spanning capabilities. We touch on 24 of the 25 core capabilities that the DOE defines.

Material science is a legacy capability that we've had at the lab. We've been able to work heavily leveraging the DOE’s manufacturing demonstration facility. It's a user facility here in Knoxville, just outside of the Oak Ridge area, but the Oak Ridge National Laboratory manages it. We’ve collaborated with the Manufacturing Demonstration Facility staff, who are experts in advanced manufacturing materials. This is an evolving space where technology continues to advance. Through this, our hydropower technical collaboration program largely targets technology developers who can come to us at the lab and say, “Hey, we have this concept, and we'd like to see if there are opportunities to advance the concept—speed up development or make it more cost-effective or both by using advanced manufacturing or new materials.”

Another program we’re working on is Rapid RUNNERS, in collaboration with numerous people, including Voith—one of the largest turbine manufacturers for hydropower—the Tennessee Valley Authority, and other entities. It uses metal additive manufacturing to manufacture Francis turbines that are inherently very complex. Basically, we 3D print using metal to build sophisticated turbomachines, starting with a 0.4-meter diameter design and then increasing to 1.5 meters and then eventually 4.3 meters, so you’re talking about a ton of metals that are being deposited to build these machines. The goal is to do it quicker to demonstrate this can be done cost-effectively.

To hear the full interview with Scott DeNeale, click here.