Instream is developing a complete hydrokinetic power solution consisting of groupings (or "arrays") of vertical axis hydrokinetic turbines (VAHTs), simple, low-cost devices that convert the kinetic energy in moving water into electricity. The modular nature of the system means it has the potential to offer a low-cost renewable energy solution that can be scaled to the physical characteristics of a waterway and to individual customer requirements. Instreamís pilot project provided valuable insight into the interactions between multiple turbines. The data obtained will allow Instream to optimize multi-turbine installations.
How it Works
Hydrokinetic power relies simply on the velocity of water. Generation systems placed in moving water will produce power without the need for dams, diversions, or reservoirs, and with minimal infrastructure or environmental impact.
VAHTs have blades rotating around a central shaft and a generator which converts the torque generated by the rotor into electricity. The shaft and generator are positioned above the waterline for system longevity and ease of maintenance, and to allow a plug-in approach to grid connection. Each turbine has its own generator and is independent of the other turbines, so there is little effect to power output if repairs or maintenance are required on an individual turbine. Each turbine can be taken offline, removed, serviced, and replaced, without consequence to other turbines.
VAHTs capture between 35 and 40 percent of the energy in moving water. The turbine rotates at a very low speed, between two and two and a half times the speed of the water (40 - 60RPM), and is able to capture energy from the water irrespective of the direction of the current. The turbine can operate at fixed or variable speed to adapt to the flow characteristics of individual sites. As the turbine is in constant motion, rather than stopping and starting and changing direction, wear and tear is reduced.