In recent years, run-of-the-river hydropower projects have emerged as a viable, low-impact alternative to existing large-scale projects. Run-of-the-river facilities use conventional hydropower technology to produce electricity by diverting river flow through turbines that spin generators - before returning water back to the river downstream.
So what is the market potential of this type of small-scale technology and how best can governments and policy makers support its ongoing development?
Michael Cutter, Vice President of Engineering and Development - US Operations at Brookfield Renewable Energy Partners, explains that run-of the river projects are located on rivers that have sufficient head (drop) to make power.
"Run-of-the-river hydro avoids the need to build large dams to store water, allowing the project to generate as conditions, river flows and the license permits," he says.
According to Mark Stover, Vice President of Corporate Affairs at Illinois-based Hydro Green Energy, the greatest advantage of the run-of-river sites they are developing is the capacity factor. Because the company is taking advantage of sites that have strong head and flow duration curves, its projects will operate anywhere between 65% to 90% of the time in any given year. From an installed capacity perspective, this means that even a small project will generate a lot of kilowatt-hours.
"When utilities start comparing our output with that of small wind or medium sized solar projects, their eyes open wide and they become quite interested because they realize that we are generating much more power, and power that is reliable and predictable," says Stover.
Hydro Green is a privately-held project development company with proprietary hydropower technology that is focused on developing new, low-impact hydropower generation at existing non-powered dams. Stover explains that, although the company began as a developer of hydrokinetic power projects, management soon realized that they could modify that technology to work at non-powered dams with head of less than 30 feet - in the belief that this was a more interesting and potentially more lucrative path to pursue.
At hydropower sites that have less than 30 feet of head, Hydro Green deploys 'plug-and-play' technology that minimizes the civil work and the costly, time-consuming installation process of conventional hydropower. Stover explains that the company's technology is modular in nature and can be mostly fabricated off-site while the management 'navigates' the regulatory process.
"Our focus at the present time is on non-powered dams on larger U.S. river systems. Depending on the site, our installation process will vary, but our goal is to always install new hydro at these dams with as little modification to the existing dam as possible," he says.
So, how best can governments and policy makers help in the promotion of run-of-the-river projects? Stover explains that HydroGreen's focus is very specific – to power non-powered dams with a low-impact technology and to operate in a run-of-river fashion. He argues that because these projects are typically smaller in nature, and tend to have little to no impacts from an environmental perspective, they are often the preferred option of environmental agencies and NGOs.
"For these types of projects, we believe that policy makers need to ensure an extension, or expansion, of existing tax incentives, and work to create a shortened, more efficient regulatory process," he says.
"We need a development process that is comparable to wind and solar projects. The process as it stands today is hindering the development of smart, responsible new hydropower projects and limiting the interest in projects and new technologies from the investment community," he adds.
His view is that if the investment community understood that the regulatory process and green energy incentives for new small hydro were the same as those for wind and solar, we’d see an explosion of hydropower growth in the U.S.
Cutter agrees, pointing out that, in the broadest sense, hydropower is a 'proven renewable generation resource' that should be recognized in state and federal policy as equal to other renewable resources.
According to the National Hydropower Association, Hydropower in all its forms accounts for around two thirds of all renewable energy generation in the U.S. As far as the run-of-the-river sub-sector is concerned, Stover explains that, for the time being, Hydro Green Energy is focused on the U.S. market which, according to a number of government and private resource assessments, could be as large as 60,000 MW. At present, the company developing a total of 28 sites across 14 states and has permits pending on another 21 sites in the United States.
"We are continuously looking for new sites or looking to acquire sites from other developers. In short, we are very busy and will have a full plate for the next decade or more," he adds.
"If we are able to successfully execute on even a small portion of the potential new low-head projects in the U.S., we will be a highly successful company," he says.
Hydro Green is also aware that there are “substantial” low-head hydro opportunities outside of the U.S., and fully intends to enter those markets “over time.” One approach that the company is taking to better understand and potentially capitalize on foreign hydro opportunities is to formally align itself with experienced, well respected companies like Engevix, a Brazilian engineering and project development firm that has participated in over 60,000 MW of hydropower development worldwide.
"Engevix sees us a way to capitalize on new U.S. hydro growth opportunities. We see Engevix as a partner to help us achieve success in the U.S. and as a great partner to potentially help us grow abroad," says Stover.
Meanwhile, Cutter explains that Brookfield believes in the future of hydropower both as an existing resource that can be enhanced and maintained - as well as new sites, both run of river and pumped storage sites, that can be developed.
"Hydropower can and should be an important part of the future energy mix," he says.
"We are completing a new project in Minneapolis and renovating another in West Virginia. We continue to look for opportunities throughout the U.S., Canada and Brazil," he adds.
In summary, the prospects for the future development of run-of-the-river projects seem relatively bright. As the renewable energy sector continues to grow, this form of hydro power looks set to emerge as an increasingly important resource.
Andrew Williams is a freelance journalist based in Cardiff, Wales, UK. His work has been published in a wide range of publications including The Guardian, The Ecologist, Green Futures, 24 Housing, Professional Broking and Strategic Risk. As well as writing for Renewable Energy World, he also writes regular articles on renewable energy for Wind Energy Update and CSP Today.
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