How NuSTREEM’s NuTECH Controller Is Making Intelligent Decisions to Run Your Hydro Site

NuSTREEM is a pioneering hydroelectric equipment manufacturer based in Mansfield, Connecticut. Its original founder recognized that future growth in the U.S. small hydropower sector would rely on modern, modular, and intelligent generation equipment and innovative deployment platforms. Building on that insight, NuSTREEM has developed an advanced control technology that works on Kaplan turbines of any size. Its modular small hydro units use the same tested, patented intelligence to optimize their performance and have demonstrated proven, measurable efficiency gains of up to 20 percent. Now, NuSTREEM’s mission is twofold: to increase the economic feasibility of new, sustainable, small hydropower development and to improve the efficiency of existing hydropower projects, both large and small. In this interview, NuSTREEM General Manager Juliann Blanford tells Hydro Leader about the advantages of the NuTECH controller and what the company hopes to learn from future applications. 

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Hydro Leader: Tell us about NuSTREEM’s mission and the products you manufacture. 

Juliann Blanford: NuSTREEM is an innovative manufacturer of modern small hydro turbine systems and equipment. We’re a team based out of Mansfield, Connecticut, within a platform of strong global companies specializing in high-tech engineering and manufacturing. Our founders started designing a modular and intelligent hydro turbine over a decade ago, when they saw a trend in the industry toward these types of systems. Our products are based on significant technological evolutions in a long-accepted hydropower turbine paradigm. In 2014, we completed two projects, a 500‑kilowatt (kW) project in Connecticut and a 100 kW project in Massachusetts, both of which have been successfully running ever since. The five 100 kW units installed in Connecticut actually power our manufacturing facility and office headquarters, which are located in a historic New England mill called the Kirby Mill. 

Our equipment is designed with the need for innovative deployment platforms in mind. Our technology allows customers to rapidly build a hydro site that is economically feasible based on average energy prices. We’ve developed a low-head Kaplan turbine called the NuTURBINE that operates at 8–40 feet of head. The brain behind this system is our patented NuTECH controller, which can be used independently on a Kaplan turbine of any size. Kaplan turbines, by means of their dual regulation, have the capability to provide high-efficiency output over wide ranges of flow and head. Our controller’s intelligence ensures optimal hydropower system output by maximizing efficiency, regardless of hydraulic or machine conditions. This means that any variable, whether it is changes in water level, impurities, wear on the turbine, blockages, or even flow variability, will be optimized to make sure the system is always running at peak efficiency.

The latest innovative system NuSTREEM has launched is called the NuCONTAINER. This is an industry-standard shipping container that can be used in place of a classic powerhouse and can house one to three turbines, depending on a site’s specifications. The turbines arrive on site inside their permanent housing, ready for installation. With the NuCONTAINER system, hydro sites can rapidly be put into operation, since they allow owners to bypass many of the costly and time-consuming geotechnical and civil efforts that traditional hydro sites require. 

Another big point of pride for us is that all our products are made in the United States. Our design team focuses on finding U.S.-based vendors, allowing us to deliver our hydroelectric equipment rapidly and bypass the difficulties caused by having a few nondomestic vendors. Our engineers and manufacturing team are dedicated to the products we make, and we offer rapidly deployed field support services; we can be on the ground anywhere in the world to support our customers’ needs. 

Hydro Leader: Please tell us about the development of the NuTECH controller and about its capabilities. 

Juliann Blanford: We were interested in continuing to innovate and in refining the automation of controls for dual-regulated turbines. We thought that there were steps to take to modernize systems beyond combination, or CAM, curves. We wanted to find a more efficient generation system that would increase return on investment at hydropower sites and make small hydro development economically feasible. The NuTECH controller is this next step forward in automated control systems: It offers upgrades to the performance of dual-regulated turbines by using transformative technology that has been proven to significantly increase efficiency. It essentially works by relying on a new-to-industry control algorithm that optimizes performance, efficiency, and reliability. 

The common method to optimize the output of a Kaplan turbine is to use CAM curves. CAM curves delivered by manufacturers are typically based either on scaled model tests; simulations, such as those based on computation fluid dynamics; or results from both types of modeling. These outdated methods can produce suboptimal results because of scaling effects, modeling uncertainty, and other factors. Index testing aims to improve manufacturer CAM curves by characterizing the turbine in operation. However, we’ve seen that this testing typically requires expensive consultants and downtime for the unit under test and optimizes for only one value of head. 

The innovative design concept of the NuTECH controller makes CAM curves and index testing a thing of the past by optimizing for each operating point. This approach eliminates any inefficiencies that would have arisen when operating under conditions different from those the CAM curve was generated under. The monetary benefits of this approach are twofold: it improves turbine efficiency over what is typically achievable via CAM curves and index testing and eliminates the expenses associated with index testing. The other innovation we’ve accomplished with the NuTECH controller is to perform the optimization without requiring a measurement of the flow through the turbine. Optimization without a flow meter has several advantages for site owners, including a significant reduction in cost, a significant reduction in installation effort and time, faster optimization convergence, and less wear and tear on actuation hardware. 

Our innovation is exciting because it enhances the system by maximizing performance and improving water use efficiency, resulting in a better economic bottom line for projects. The NuTECH controller puts intelligence behind decisions about how to move water through a turbine and is a new, superior method for optimization. It allows owners to generate more energy with less water. The NuTECH controller’s patented technology enables the active optimization of a turbine’s runner blades and wicket gates, regardless of variables and without the need for a CAM curve. The increase in efficiency allows owners to generate more power. 

The technology can be easily installed and integrated into existing turbines and control systems and has a wide variety of turbine applications. It’s a plug-and-play installation that sits on top of existing programmable logic controllers (PLCs) and that allows us to leverage current architecture. The controller won’t compromise safety, efficiency, or control. 

Hydro Leader: Have you been able to demonstrate and prove the effectiveness of this technology? 

Juliann Blanford: Yes. We established the value of the controller through simulation and empirical testing, both of which demonstrated significant improvements over existing methods. The data and results we gathered were published in our NuTECH controller case study. We found that, when operating with the NuTECH controller, the turbine achieved efficiency gains throughout the operating range, with the most statistically significant improvements at low flows. 

The site had an ultrasonic flow meter that measured the total flow in the penstock feeding the site. Testing was performed with only the one turbine generator unit controlled by the NuTECH controller in operation. In order to have a baseline for comparison, the performance of the unit was also evaluated with the original CAM curve. 

As it modernizes, the hydro industry is evaluating new approaches to recapture energy lost through inefficiency, squeezing out every last bit of available generation. What the NuTECH controller offers is a boost to the performance of existing systems, and it can integrate seamlessly into existing systems. We’re offering efficiency improvements for all turbines, from the smallest to the largest.

Hydro Leader: Why is bringing a product like the NuTECH controller to market so important? 

Juliann Blanford: As I mentioned before, one of our main goals as an organization is to improve the efficiency of existing hydro sites. With the NuTECH controller, we’ve unlocked a way to elevate the efficiency of our already installed baseload without having to install new turbines or generation capacity. Our controller is offered as an optimization upgrade to existing control systems and can be applied to current site infrastructure, providing for a better return on investment for site owners while also making hydropower a leader in our energy transition to a carbon-free grid. 

Our NuTECH controller can be thought of as an efficiency optimizer. It integrates with Kaplan turbines of any size and interfaces via multiple standard communication protocols with existing facility controls. Because of its flexibility, the NuTECH controller can be installed on a lot of existing hydropower infrastructure. We have a goal, which we’re working on implementing through our NuTECH controller partner program, of doing 500 installations with our proven efficiency lift of 0.25–20 percent. 

NuSTREEM’s hope is to use the NuTECH controller across a variety of hydropower applications, from retrofits to greenfield sites. We want to simultaneously maximize the power production our customers receive from their assets while making sure hydro is a clean, reliable, and efficient source of renewable energy. 

Hydro Leader: You recently launched the NuTECH controller partner program. What is the goal behind this project? 

Juliann Blanford: We were excited to observe during testing at our Connecticut site that the use of the NuTECH controller resulted in efficiency increases of over 20 percent at lower flows. Going into the test, we hypothesized we would see a lift of around 6 percent, since the site was already using a CAM curve to optimize for efficiency. We’d like to see how this carries over to other sites, and we felt that the best way to do this would be to offer NuTECH controllers at no charge to three sites with the agreement that we would be able to access the performance data and document the efficiency improvements achieved. The sites each receive a controller to increase efficiency, and NuSTREEM receives data to enhance our product research even further—it’s a win-win situation. 

Hydro Leader: Does the controller work on hydro turbines other than those manufactured by NuSTREEM? 

Juliann Blanford: Yes. The NuTECH controller works with any Kaplan turbine. We expect that dual-regulated turbines installed at sites with a high flow variability would see the largest efficiency increase. NuSTREEM provides expert support to site operators and engineers, making the setup and integration of the controller a low-risk undertaking. The system is designed to reduce installation effort by minimizing the extent of modifications to the facility PLC. Our approach is to provide additional performance while also addressing and prioritizing the site owners’ concerns. For example, the NuTECH controller offers customizable intervals and can make continuous program adjustments at an interval directed by the site operator to minimize the risk of overuse of the actuation hardware. 

Hydro Leader: What is the advantage of your controller system for owners with multiple hydro locations? 

Juliann Blanford: The NuTECH controller has cellular connectivity that allows for remote, real-time monitoring and operation. You’re able to see what’s going on in the turbine and control it from anywhere in the world. This feature can be turned completely on or off at the preference of the operator. The sensors can be used to monitor the health of the turbine. Remote monitoring is ideal for situations in which one operator handles multiple locations or in which sites and applications are isolated or otherwise not easily routinely accessible. 

Hydro Leader: How long does installation generally take? 

Juliann Blanford: The fact that the NuTECH controller interfaces with the owner’s controls and not directly with the turbine minimizes installation time. The actual installation time is site dependent. On an ideal site, installation could take as little as 1 day; we would then take another day to the demonstrate proper operation of the controller. 

Hydro Leader: Where can people go to learn more about the NuTECH controller, your other technology, and your company? 

Juliann Blanford: To find our case study, brochures, videos, and more, visit our website at or follow us on social media @NuSTREEM. We’ll be at a few conferences this year, including HydroVision and Clean Currents, so stop by to say hi and check out our booth! We’re always open to giving tours of our facility in Mansfield, Connecticut, whether in person or virtually, so reach out to us at to set something up. 

Juliann Blanford is the general manager of NuSTREEM. She can be contacted at