“Run-of-river” hydro power, gentler and smaller-scale than massive hydroelectric projects that irretrievably flood huge areas of land, may become a $1.4 billion-dollar industry in the next 10 years, according to Tocardo International BV, a Dutch turbine maker.
To many, run-of-river technology represents the most environmentally friendly hydropower because it lacks the enormous investment and impacts of traditional impoundment projects. Tocardo general director Hans van Breugel explains its appeal to companies and investors:
The advantages of river-turbine projects are you don’t need to build infrastructure, they’re easy to install and maintain, and they can be easily connected to the local grid. Within a year you can start installing these projects, whereas hydropower projects can take 12 to 15 years.
The projects also involve nearly zero greenhouse gas emissions and no mercury or particulate pollution.
Run-of-river is actually a diversion strategy that redirects part of a downward-flowing waterway through a pipe down the head (elevation change) to spin turbines and generate electricity at a lower powerhouse. From the powerhouse, the water then rejoins its source. Upstream storage (pondage) is minimal and used only on a daily or weekly basis. It’s an ideal generation scheme for remote, mountainous areas and has been used with much success in areas of the Pacific Northwest and Himalayan Asia.
The infographic above from greenenergyfutures.ca shows how the process works. Key to impact prevention is flow maintenance monitoring (i.e., ensuring that the waterway never drops below the level needed to protect ecological health of water and habitats, which are diverse because of the topography). Fish ladders can enable migration for species such as salmon and white sturgeon.
Tocardo says that its turbines are easily installed, reliable, and low-maintenance. River sites, inshore sites, and offshore sites can all use the same turbines, either on or off the grid. The facilities run from 500kWh to 1 MWh and the technology already is cost-competitive with fossil fuels, Van Breugel says.
The company first implemented its design to harness tidal streams at Den Oever, Holland. There it has been generating power for five years. Two years ago, Tocardo started working in Nepal, and it expects to expand soon to South America, particularly Chile, Brazil, and Argentina.