The U.S. Department of Energy’s (DOE) Water Power Technologies Office (WPTO) funds important hydropower, marine energy, and freshwater hydrokinetic research at U.S. national laboratories, private companies, and universities. Its hydropower portfolio covers new technology, hydropower’s relationship with the electric grid, fleet modernization, environmental mitigation, and data science. In this interview, WPTO Hydropower Program Manager Timothy Welch tells us about the focuses of the office’s research; some of its specific projects, including the development of modular hydropower projects in remote locations in Alaska; and the importance of pumped storage for the future of the grid. 

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

Timothy Welch: I’m the manager of the hydropower program at WPTO. I oversee the hydropower program research and development portfolio. I’m a fishery biologist by training and have been in the hydropower community for over 30 years. I’ve worked for the DOE for 6 years and previously worked for the Federal Energy Regulatory Commission in hydropower licensing for 25 years. 

Hydro Leader: What is WPTO and what does it do? 

Timothy Welch: WPTO covers a few major programming areas: the hydropower program, which is what I’m a part of; the marine energy program, which includes wave and tidal marine projects; and the freshwater hydrokinetic project, which covers projects that don’t need a dam to operate and operate strictly by flow. My part of the portfolio focuses on five major activity areas. The first one is innovation for low-impact hydro, which covers new technology. The second is Water Innovation for a Resilient Electricity System (HydroWIRES), our newest activity area, which focuses on hydropower’s relationship to the bigger electric grid and how it facilitates variable renewables like wind and solar. The third area is fleet modernization, which focuses specifically on the existing hydropower fleet and how we can use digitalization to bring it into the 21st century. The fourth area is environmental and hydrologic sciences, which looks at environmental mitigation strategies for hydropower and at fish tags and fish passage systems. In the hydrologic science area, we use new sensors to capture watershed data that enable us to get a handle on what hydrological regimes might look like in the future under different climate scenarios. The fifth area is data access, which covers all the types of data that are collected through the projects we fund. We’re in charge of the largest existing comprehensive hydropower database in the country, HydroSource, which is a project through Oak Ridge National Laboratory. 

Hydro Leader: Does WPTO do research in house, or do you mainly fund other people and programs? 

Timothy Welch: We mainly fund other people and programs. We have two major areas of funding. The first is the national laboratories, including Pacific Northwest National Laboratory, Oak Ridge National Laboratory, the National Renewable Energy Laboratory (NREL), Idaho National Laboratory, and Argonne National Laboratory. These laboratories do the bulk of the hydropower research. Our other area of funding is the private sector and universities. We provide them funding through a variety of mechanisms. The most noteworthy are our Funding Opportunity Announcements (FOAs), in which we announce specific topic areas in which the private sector can submit proposals for funding. We usually have one highly funded FOA a year. We develop these specific topic areas through our strategic planning. We have a lot of specialists in different research areas, including fish biologists like me and engineers, because we need to be able to approve the methodologies associated with different research projects and review the results and reports. We also develop our strategic plan based on conversations and workshops with the hydropower industry and partnering federal agencies. I currently have a staff of five federal employees and receive support from three contractor employees. 

Hydro Leader: What is the current state of hydro in the United States, and where do you see the biggest opportunities for advancement? 

The Village of Igiugig, Alaska, installed its first RivGen hydrokinetic turbine in 2019 as part of a multiyear effort launched in 2018 via a WPTO award.

Timothy Welch: I always start off by saying that the era of Hoover Dam and Grand Coulee Dam has ended. In the United States, we saw significant growth in the hydropower industry in the 1940s, 1950s, 1960s, and a little bit in the 1970s, but then it started tailing off. Today, we aren’t seeing much growth in the area of big dams, and when we talk about growth, most people still think of building new projects. What we’re talking about is using the existing fleet in a new and innovative way. 

The real growth in hydropower falls into two categories: new stream reach development and, most notably, the development of nonpowered dams. There are 90,000 dams in the United States, of which only 2,500—or less than 3 percent—currently generate electricity. We think there is the potential for at least 6–10 gigawatts (GW) of growth at nonpowered dams in the United States. Our research is focused on coming up with new, innovative ways of powering nonpowered dams. 

We’re looking at new stream reach development in a way that is totally different from how it has been done historically. Historically, the design paradigm for building a project in a new stream reach area was to build your project and then go through the regulatory process by asking resource agencies and environmental organizations what needed to be done to mitigate its effects. Our new design paradigm, which is called standard modular hydro, takes the approach of using modules, which will hopefully someday be standard, and arranging them in a manner that not only supports but enhances the functionality of the stream. In other words, you move into your design phase by first looking at the environmental attributes of the stream reach and then designing your project to mitigate or enhance those stream functions. It’s much easier to go into a conversation with a resource agency saying that your project is going to provide certain benefits for the stream reach and is going to generate electricity as well. It’s a real paradigm shift. We’re applying the same principles to nonpowered dam development. 

Hydro Leader: Would you tell us about your efforts to promote hydro development in remote communities and why it is important? 

Timothy Welch: We think that hydro has a huge role to play in remote communities. Hydropower can act as the foundation for something like a microgrid in remote communities and can help with intermittent outages because of its flexibility. In the city of Cordova, Alaska, we are cofunding a project called the RADIANCE Project with the DOE’s Office of Electricity. It is looking at hydropower and pumped storage as the cornerstone of a microgrid. 

The multifunctionality of a hydropower project can be key to community health, especially with respect to enhancing water quality, enabling groundwater recharge, creating recreational opportunities, and creating new fish habitats. Small hydropower plays a key role in remote communities, particularly in communities that depend on irrigation. Hydropower can play a huge role in providing a revenue stream for the modernization of irrigation systems in rural communities, including the replacement of open ditches with pressurized piping and the use of more precise and advanced technology in agriculture. 

Hydro Leader: Would you tell us about the project in Alaska that you are working on with Littoral? 

Timothy Welch: The Littoral project is one of our standard modular hydro projects, and it would be a new stream reach development. If there’s anywhere in the country where new stream reach development can help bolster real estate, it’s probably Alaska. There are many streams and sites without hydropower. Littoral partnered with Oak Ridge National Laboratory to design a standard modular hydropower facility in Fair Creek, Alaska. They are coming up with two different designs: a conventional design and a modular design that uses a form factor module, which looks something like a shipping container and can be used to put together a dam almost like Legos. Littoral is going to compare the costs of the conventional design and the standard modular design. Right now, we think that using the modular approach might reduce the cost of the facility by 15–30 percent. 

Hydro Leader: Is WPTO’s role in the project funding that research? 

Timothy Welch: Yes. Our role is funding, and Oak Ridge National Laboratory is providing technical assistance. 

Hydro Leader: How do you see pumped storage in the United States developing over the coming years? 

Timothy Welch: Pumped storage hydropower is the least expensive and the most used method of bulk energy storage in the world. It makes up 95 percent of all bulk energy storage worldwide. Energy storage in general has a huge role to play amid the increase in variable renewables like wind and solar. Pumped storage is reliable when the sun sets, the wind dies down, and demand increases. Pumped storage projects can pump water all day and then release it and generate power as it is needed. We think there’s going to be an uptick in pumped storage development. In fact, the hydropower vision report we did in 2016 projected, based on modeling by NREL, that there will be 35 GW of new pumped storage by 2050. 

However, there are some significant technical hurdles that we need to overcome, and this is where we’re focusing our efforts. The biggest one is the high capital cost of building these projects, which can be in the tens of millions of dollars. Argonne National Laboratory just came out with a guidebook for valuing pumped storage projects that demonstrates how these long-term assets can last for 50–100 years and pay dividends. We’ve developed a methodology for developers to show the facilities’ value and thus to get financing. 

We are also working on technical advances to help lower the costs of construction, particularly in new tunneling techniques. We’re also looking at a more modular approach to pumped storage that might involve a series of 5–10 megawatt pumped storage projects. We’re about ready to release a report drawn up by the Obermeyer Corporation about constructing a small, underground, modular pumped storage project that does not require an underground powerhouse. The pump and turbine facility are in a shaft that can be easily lifted for maintenance. That eliminates the need for tunneling underground or driving vehicles down to a powerhouse. We think there are big cost savings there. 

Oak Ridge National Laboratory is also looking at the concept of building a pumped storage project by using an existing lower reservoir and constructing a modular upper reservoir. To minimize environmental effects, a membrane in the lower reservoir would keep the water for the pumped storage project separate from the natural waters. There would be no mixing and no issues associated with water quality, temperature, or fish entrainment. It would be a closed-loop project in something like an open-loop situation. We’re testing different membrane concepts and working to enable the use of this concept on a greater scale. We need to do a lot more work on making pumped storage projects more flexible and able to react more quickly to changes in the grid as well. 

Hydro Leader: Are you doing any work that would help address water quantity issues related to climate change and how they might affect power production? 

Timothy Welch: DOE is preparing to issue our third 9505 Assessment, which is a technical report to Congress, next year. The 9505 Assessment looks at the effects of climate change on the federal hydropower system. We do a new version every 2 years. We’ve worked on taking global climate models and downsizing them to a watershed level to look at different climate scenarios and show how they affect hydropower generation in the federal fleet. Since our first report in 2013, we’ve made those models more granular and are coming up with more accurate answers. What we want to do next is to expand that analysis to the nonfederal fleet. 

We’re also looking at other areas. NREL is working on water risk with a changing hydrologic table and trying to identify the long-term risks that hydropower operators need to face. How do you model them and how do you predict them? We’re also investing in better forecasting techniques, because the key for long-term planning is better short- and long-term forecasts. 

Hydro Leader: What do we need to do to meet national emission-free goals? 

Timothy Welch: I can’t speak for all the energy sectors, but achieving 100 percent decarbonization will require a much greater deployment of wind, solar, and other renewables. We think that hydropower will play a huge role, too, just because it’s such a long-lived asset, it already exists, and its flexibility can allow for the variable nature of both wind and solar. We recently issued a report called the North American Renewable Integration Study, which we did in partnership with Canada. It shows that hydropower has a huge role to play with the increasing deployment of variable renewables. 


Timothy Welch is the hydropower program manager at the U.S. Department of Energy’s Water Power Technologies Office. He can be contacted at