How it works

The hydroEngine employs a unique linear drivetrain with two parallel shafts and carbon fiber belts between the shafts to make a horizontal loop. Cups analogous to Pelton turbine cups are mounted by cross bars on the belts so that the cups make two parallel rows outboard of the belt. A unique, flat nozzle projects flow from the center out to the two rows of cups. Flow is converted to force in the belts much like Pelton cups react with the water stream. This achieves Pelton performance profiles for low head, high flow sites as many Pelton-like cups are simultaneously impacted by the flow projected in the flat stream. Either shaft drives a conventional generator.

Watch the video below to see how the hydroEngine works.

Operations of the hydroEngine

Advantages

The hydroEngine delivers high performance and low cost for high flow, low head sites. It is more compact and less expensive than conventional lower head Kaplan or Archimedes turbines, while delivering similar power.

In addition, because it is an impulse turbine, it does not cavitate, enabling simpler civil works and reducing excavation by as much as 80% compared to the conventional bulb, Kaplan, or other reaction-type turbines, allowing for higher flexibility and lower cost.

Modular, mass produced

15% to 20% less expensive turbine

Simple plant, minimal excavation

30% to 50% lower installed cost

Compact, high performance

3 to 5 cents per kWh

Moderate operating pressure

Fish friendly operation

Competitive Advantages

	hydroEngine	Kaplan	Propellers	Archimedes Screw	Crossflow
Turbine Size	Compact	Moderate	Large	Large	Large
Cavitation	No	Yes	Yes	No	No
Civil Works & Excavation	Low	Substantial	Moderate	Moderate	Moderate
Flow Range	Wide	Wide	Narrow	Wide	Wide
Fish Friendly	Yes	No	No	Yes	Maybe
Cost	Low	Med to High	High	High	Med to High

The reduced excavation, shorter penstock, and simpler configuration of the hydroEngine allows 30% to 50% cost savings in civil works, compared to conventional reaction turbines.

Performance & testing

Natel has extensively verified both generation output and durability of hydroEngine through field-verified hydraulic scale testing and a rigorous component fatigue testing program.

Hydraulic Test Facility

To support ongoing hydroEngine R&D efforts, Natel built a fully instrumented hydraulic test facility at its headquarters in Alameda. The facility can test a production scale hydroEngine at 0.3 cms at 10 m of head and was built to the PTC-18 standards for hydro turbine performance testing.

The in-house facility provides data to validate computational fluid dynamics models for both design verification and for optimizing site configurations. The facility utilizes a recirculating variable-rate pump-driven loop, with high precision flow, pressure, torque, speed measurements.

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Fatigue testing

Natel’s Fatigue Lab has the ability to life-cycle test all wear components of the hydroEngine. Dedicated test rigs put components through high-cycle fatigue tests at full scale.

The testers are designed to go through high loads and tens of millions of cycles to verify life of core components. Focus has been primarily on long running fatigue testing, and on exploring new materials and methods of fabrications. The test is also a great way to see the hydroEngine in operation at our Alameda facilities.