For years, many of the country’s low-head river systems have gone undeveloped due to several reasons, including economic viability, utility value, and limitations of conventional hydropower technologies. Conventional hydropower systems utilize fixed-speed turbines designed for high-speed, constant flow rate environments, such as those found behind large dams. However, when it comes to the rapidly changing, variable flow rates associated with low-head rivers, these systems are generally unable to meet their requirements.
Natel Energy takes a different approach than other companies
Unlike many other companies that develop low-impact hydroelectric technologies, Natel Energy takes a completely different approach to designing its hydroelectric systems. The core idea behind Natel Energy’s hydroelectric system is that it must be flexible.
All machine components must be able to adjust to changing conditions. The use of variable-speed turbine designs makes Natel Energy’s hydroelectric system adaptable to the constantly changing conditions found at most low-head river sites.
These designs are based on Natel’s Restoration Hydro concept
In contrast to traditional hydroelectric development methods that attempt to make rivers behave like ideal engineering inputs, Natel’s hydroelectric systems are designed to adapt to the actual conditions present in the river.
Adaptability and flexibility are key components of variable-speed turbine designs
One key benefit of variable-speed turbine designs is that they enable turbines to generate electricity at a consistent level across a wide range of flow rates. This is particularly beneficial for low-head applications where electricity can be produced continuously without having to store large quantities of water upstream or aggressively controlling flow downstream.
Additionally, since these turbines produce electricity at a relatively consistent level under a wide variety of flow conditions, the amount of mechanical stress placed on the turbine is significantly reduced compared to what would occur with traditional fixed-speed turbines. In practical terms, the turbines adapt to the river conditions – not the other way around.
In addition to producing electricity consistently at a given site, Natel Energy’s modular system design allows for the simultaneous production of power and restoration efforts within the watershed. Rather than displacing watershed restoration activities, Natel Energy’s hydroelectric system allows for the simultaneous completion of both activities. Within the context of Natel’s Restoration Hydro framework, sites such as alluvial pocket areas are identified where ecological restoration and low-head generation can occur together.
Compatibility with the environment is central to expanding hydropower into new contexts via flexibility
The ability to replicate the same type of modular system design throughout diverse sites presents another opportunity for expanding hydropower into new locations. Standardized component parts used in Natel Energy’s turbine systems reduce engineering costs and shorten project development times for subsequent projects utilizing similar hydraulic characteristics.
Research funded by the Department of Energy has established criteria and design guidelines for identifying optimal locations for generating electricity via low-head hydroelectric systems. Consequently, low-head hydroelectric development has transitioned from custom-designed projects to repeatable infrastructure – a necessary prerequisite for scaling adoption of distributed hydropower throughout the U.S.
Why does flexibility matter now?
While no one anticipates replacing large dams with low-head hydroelectric facilities in terms of overall capacity, their value lies elsewhere. As discussed earlier, flexible variable-speed systems can address gaps created by intermittent solar and wind outputs, provide localized grid resilience with respect to renewable energy sources featuring varying output profiles, and accomplish this with virtually no impact on existing landscapes.
As highlighted by Natel Energy’s advances, there exists a growing consensus – the future of hydropower growth will depend far less on finding additional large rivers and more on implementing better technology. By synchronizing turbine performance with nature’s variability, low-head sites may now be capable of producing electricity without negatively impacting ecological objectives.
