Hyper-Chute

Rivers, streams, canals, tidal channels, ocean currents and hydroelectric discharge flows quietly move enormous volumes of water every day. Yet most of these resources receive little attention because they move too slowly for the turbine-based in-stream energy technologies currently under development.

While navigating his boat through the five-mile-per-hour zone of California's Berkeley Marina, Joseph Santos lowered a one-gallon bucket into the water to wet his bait. When it nearly pulled away from his hand, he realized that a larger bucket would have been impossible to hold, and he wondered, "Can this pull force be used to drive a generator?"

As a parent who has been concerned about climate change since childhood, Santos recognized the profound implications of that question if the answer proved to be yes. Drawing on more than 45 years of experience working on diesel, turbine, gas, electric, hydraulic and pneumatic power systems, he bootstrapped and self-funded a project that he knew could prove impossible. He built a proprietary laboratory and 3,500-gallon flow bench and developed several prototypes that led to the world’s first operating water piston engine. His research resulted in the patented HydroChute Water Piston Engine (WPE), patented directional power-conversion concepts, an AIAA publication and recognition by Energy Tech Review as its Top In-Stream Energy Extraction Technology of 2026.

Unlike turbine-based in-stream energy technologies, which largely rely on velocity and typically require a 2-foot vertical drop, 6 to 9 feet of vertical head, or water velocities above approximately 6 ft/sec, HydroChute's development is focused on shallow waterways with flow velocities of 3 to 6 ft/sec and coastal tidal ranges as low as 6 feet, where channelized flows can produce several inches of velocity head and significant dynamic pressure. Field measurements at California's Brisbane Lagoon recorded water velocities exceeding 4 ft/sec for more than 4 of 7 hours through two 10 × 10-foot tidal flows during a 3.5-foot tidal change in San Francisco Bay. These observations support further investigation of low-range coastal tidal lagoons as a renewable energy resource. Currently, the prototype extracts power from approximately 1 inch of velocity head under laboratory conditions.

At the heart of the WPE is a lightweight, framed, flexible, Marine-grade drogue enclosed within a cylinder. Flowing water repeatedly expands and collapses the drogue, creating power strokes that are converted into mechanical power.

When laboratory weight-lifting experiments produced greater mechanical work than anticipated, they raised new questions about how the system concentrates and transfers energy. When the drogue expands, a near-stationary pressure field forms ahead of it, and measurable hydraulic head develops in the pen area leading into the cylinder.

“Combined with a 10–20 percent flow bypass with increased velocity and lower pressure behind the drogue, these observations suggest a three-dimensional flow field shaped by the actual behavior of water rather than assumptions drawn from airflow simulations,” says Dr. Yuanyuan Xie at CSU Fresno.

Limited by the capabilities of his current test facility, Santos' 2-cylinder prototype has repeatedly demonstrated self-reciprocation while driving an electrical generator and hydraulic pump under varying loads and velocities, despite being built largely from repurposed off-the-shelf components. Like the earliest combustion engines, the WPE is only beginning its engineering evolution. Continued refinement of transition control, piston-to-cylinder fit and alignment, intake geometry, helical water flow and tuned exhaust are expected to improve performance.

Designed for surface deployments where energy is highest, HydroChute emphasizes mechanical simplicity, modular construction, fish-safe operation and minimal supporting infrastructure to reduce costs and simplify installation, maintenance and deployment to make renewable energy extraction practical in waterways not previously considered for development.

If successful, these design characteristics, combined with durable, recyclable materials and environmentally responsible engineering where practical, could offer a holistic approach to developing what may be one of our planet's largest overlooked renewable energy resources.

The next phase moves into natural waterways using a mobile research platform to evaluate performance, scalability and deployment while demonstrating the concept as a Mobile Renewable Energy Backup Unit (MORBUG). Hyper-Chute Systems is actively seeking partners to advance field trials.

One simple observation led to a fundamental question: Can ultra-low-speed, high-volume water flows—potentially Earth’s largest overlooked renewable resource—become practical sources of energy?

If the answer proves to be yes, the implications extend far beyond tidal lagoons and a single technology. Additional potential applications include hydroelectric dam discharge flows, rivers, irrigation canals, open-ocean tidal currents and other managed waterways where large volumes of water move continuously at modest velocities.

If the answer is no, the research will still have contributed valuable knowledge about flowing-water behavior. Either outcome advances our understanding of fluid dynamics.

With patents in multiple countries, Hyper-Chute Systems hopes to encourage international collaboration so this new renewable energy resource can be evaluated, refined and, if successful, deployed quickly to help combat climate change.