In-Stream Hydrokinetic Turbines

Detailed overview of innovation with sample startups and prominent university research

What it is

In-stream hydrokinetic turbines are devices that capture energy from the movement of water in rivers, tidal currents, or ocean currents without the need for dams or barrages. These turbines are typically submerged or partially submerged in the water and generate electricity from the kinetic energy of flowing water.

Impact on climate action

In-Stream Hydrokinetic Turbines within the Hydropower sector bolster climate action by harnessing river currents to generate renewable energy. By tapping into continuous flow without damming rivers, these turbines minimize environmental disruption, reduce reliance on fossil fuels, and contribute to a cleaner, more sustainable energy mix, mitigating carbon emissions.


  • Turbine Types: Different types of in-stream hydrokinetic turbines exist, including:
    • Horizontal-axis turbines: These turbines resemble underwater wind turbines and are typically deployed in rivers or tidal currents with consistent flow directions.
    • Vertical-axis turbines: These turbines have a vertical axis of rotation and can capture energy from various flow directions, making them suitable for turbulent or unpredictable currents.
    • Oscillating hydrofoils: These devices use hydrofoils that oscillate up and down in the water flow to generate electricity.
  • Hydrodynamics: Hydrokinetic turbine design and performance are governed by the principles of hydrodynamics, which deal with the motion of fluids and the forces acting on objects immersed in fluids.
  • Power Conversion Systems: Hydrokinetic turbines use generators and power electronics to convert the mechanical energy from the rotating blades or oscillating hydrofoils into electricity.
  • Anchoring and Mooring Systems: In-stream turbines are typically anchored or moored to the riverbed or seabed to maintain their position in the current.
  • Environmental Considerations: Hydrokinetic turbines need to be designed and deployed in a way that minimizes their impact on aquatic ecosystems and marine life.

TRL : 5-7 (depending on the specific hydrokinetic turbine technology)

Prominent Innovation themes

  • Advanced Turbine Designs: Researchers and startups are developing in-stream hydrokinetic turbine designs with improved efficiency, durability, and environmental performance. This includes optimizing blade shapes, materials, and control systems to maximize energy capture while minimizing impacts on fish and other aquatic life.
  • Resource Assessment and Site Selection: Advanced modeling and data analytics techniques are being used to assess hydrokinetic energy resources and identify optimal sites for turbine deployment, considering factors such as water flow velocity, turbulence, and environmental sensitivity.
  • Hybrid Hydrokinetic Systems: Combining in-stream hydrokinetic turbines with other renewable energy sources, such as solar PV or wind power, can create hybrid systems that offer increased energy generation consistency and improved grid stability.
  • Environmental Monitoring and Mitigation: Technologies are being developed to monitor the environmental impacts of hydrokinetic turbines and mitigate potential risks to aquatic life. This includes using fish-friendly turbine designs, implementing fish passage solutions, and monitoring fish populations and behavior.

Sample Global Startups and Companies

  • Verdant Power:
    • Technology Enhancement: Verdant Power specializes in the development and deployment of underwater turbines for generating electricity from the kinetic energy of flowing water in rivers, tidal channels, and other water currents. Their turbines, known as Free Flow Systems, are designed to be installed in-stream without the need for dams or barrages, harnessing the continuous flow of water to generate renewable energy.
    • Uniqueness of the Startup: Verdant Power stands out for its focus on in-stream hydrokinetic turbines and its innovative approach to tidal and river energy generation. Their Free Flow Systems are designed to minimize environmental impact, protect aquatic life, and provide a reliable and cost-effective source of renewable energy from water currents.
    • End-User Segments Addressing: Verdant Power serves utilities, municipalities, and developers seeking clean and sustainable energy solutions from in-stream hydrokinetic sources. Their turbines are deployed in tidal energy projects, riverine applications, and off-grid microgrids, providing renewable electricity for communities, industries, and remote locations.
  • Orbital Marine Power:
    • Technology Enhancement: Orbital Marine Power specializes in the development of floating tidal energy systems, including the Orbital O2 turbine. This system features a floating platform with two horizontal axis turbines submerged beneath the surface, capturing energy from tidal currents. The turbines rotate to face the direction of the flow, maximizing energy capture and efficiency.
    • Uniqueness of the Startup: Orbital Marine Power stands out for its focus on floating tidal energy systems and its innovative turbine design optimized for marine environments. The Orbital O2 turbine is designed for easy installation, maintenance, and scalability, offering a flexible and reliable solution for harnessing tidal energy in coastal and estuarine areas.
    • End-User Segments Addressing: Orbital Marine Power serves coastal communities, utilities, and renewable energy developers seeking tidal energy solutions. Their floating tidal turbines are deployed in commercial tidal energy projects, grid-connected installations, and remote coastal regions, providing clean and predictable electricity from tidal currents.
  • Instream Energy Systems:
    • Technology Enhancement: Instream Energy Systems specializes in the development of in-stream hydrokinetic turbines for generating electricity from rivers and streams. Their turbine systems are designed to be installed directly in flowing water, utilizing the kinetic energy of the stream to drive electricity generators. These turbines are typically installed on fixed or floating platforms, depending on the specific site conditions.
    • Uniqueness of the Startup: Instream Energy Systems stands out for its focus on in-stream hydrokinetic turbines and its modular turbine designs suitable for various water environments. Their systems are designed for easy deployment and maintenance, allowing for rapid installation and scalability in riverine settings.
    • End-User Segments Addressing: Instream Energy Systems serves rural communities, off-grid installations, and water resource authorities seeking decentralized energy solutions from in-stream hydrokinetic sources. Their turbines are deployed in river-based microgrids, remote villages, and irrigation systems, providing reliable and sustainable electricity from local water resources.

Sample Research At Top-Tier Universities

  • University of Washington:
    • Research Focus: The University of Washington is at the forefront of research on In-Stream Hydrokinetic Turbines, focusing on developing novel turbine designs, hydrodynamic modeling techniques, and environmental monitoring tools for harnessing energy from flowing water in rivers, tidal channels, and marine currents.
    • Uniqueness: Their research involves designing low-impact turbine systems that can efficiently extract energy from water currents while minimizing adverse effects on aquatic ecosystems, sediment transport, and fish passage. They also investigate the integration of renewable energy storage technologies, grid interconnection strategies, and power electronics for optimizing energy conversion efficiency and grid stability.
    • End-use Applications: The outcomes of their work have applications in off-grid electrification, remote communities, and marine renewable energy parks. By harnessing the kinetic energy of flowing water, the University of Washington’s research contributes to reducing reliance on fossil fuels, mitigating climate change impacts, and promoting sustainable development of water resources.
  • University of Edinburgh:
    • Research Focus: The University of Edinburgh conducts pioneering research on In-Stream Hydrokinetic Turbines, leveraging its expertise in fluid dynamics, structural engineering, and renewable energy systems to develop innovative turbine technologies for capturing energy from rivers, estuaries, and tidal flows.
    • Uniqueness: Their research encompasses the design optimization, performance testing, and field deployment of hydrokinetic turbines in diverse hydrological environments, including shallow rivers, deep ocean currents, and coastal zones. They also explore advanced materials, coatings, and corrosion protection techniques to enhance turbine durability, reliability, and maintenance intervals.
    • End-use Applications: The outcomes of their work find applications in marine renewable energy projects, coastal protection schemes, and water resource management initiatives. By harnessing the power of in-stream hydrokinetic turbines, the University of Edinburgh’s research supports the transition to a low-carbon energy system, fosters innovation in marine engineering, and creates opportunities for sustainable economic development.
  • National Renewable Energy Laboratory (NREL):
    • Research Focus: NREL is engaged in cutting-edge research on In-Stream Hydrokinetic Turbines, leveraging its world-class facilities, numerical modeling capabilities, and field testing infrastructure to advance the development and commercialization of hydrokinetic energy technologies.
    • Uniqueness: Their research spans the entire technology innovation chain, from fundamental research on turbine aerodynamics and hydrodynamics to applied research on system integration, grid compatibility, and environmental impact assessment. They also collaborate with industry partners, regulatory agencies, and international organizations to address technical, economic, and policy challenges facing the deployment of in-stream hydrokinetic turbines.
    • End-use Applications: The outcomes of their work have applications in riverine energy projects, coastal infrastructure development, and renewable energy portfolio diversification. By supporting the development of in-stream hydrokinetic turbines, NREL’s research contributes to expanding renewable energy capacity, enhancing energy security, and reducing greenhouse gas emissions in a sustainable and environmentally responsible manner.

commercial_img Commercial Implementation

In-stream hydrokinetic turbine technology is still in the early stages of commercialization, but several pilot projects and demonstration installations have been deployed around the world. For example, Verdant Power has installed tidal turbines in the East River in New York City, demonstrating the potential of tidal energy in urban environments.