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The hydroEngineDelivering utility-scale,reliable, renewable energy.

®

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Table of contents01. Operations ...................................................................... p.3

02. Product Lines ................................................................. p.4

03. Operating Range .......................................................... p.5

04. Installation ...................................................................... p.6

Turbine Placement Guidelines

05. Water to Wire Package ............................................. p.8

06. Plant Safety ..................................................................p.10

Control Panel

Flow Control

Runaway/Overspeed Prevention

Avoiding Water Hammer

07. Monitoring and Maintenance ...............................p.12

Materials of Construction

Debris Management and Water Quality

Maintenance

Cavitation

Temperature Changes

Monitoring/SCADA

08. Fish Passage ...............................................................p.15

Fish Friendly

Watershed Friendly

OperationsThe hydroEngine® combines the simplicity, low cost,

and freedom from cavitation of impulse turbines

such as Crossflow or Pelton turbines and is delivered

in a compact, easy-to-install package comparable

in size and power output to more costly to install

Kaplan-type turbines.

The device is well suited to low head hydropower

applications because, due to its unique mechanical

configuration, it can generate from large flows at

low heads, while maintaining high shaft speed and

efficiency.

The hydroEngine uses a unique 2-stage axial-

flow pattern optimized for low-head large-flow

hydroelectric generation. Water, after passing

through a screened intake, is conveyed through a

pipe or penstock and enters the engine through a set

of wicket gate-like guide vanes or a flow-controlling

nozzle. Flow enters the hydroEngine and is directed

through a cassette formed by two shafts with belts

running between the shafts and blades fixed to belts.

After imparting energy to the moving blades on the

first side of the cassette, the water flows through

a cascade of guidevanes fixed between the moving

belt and blade runs, and finally, imparts energy

to the second cascade of moving blades.

The flow angle and/or rate is adjusted

automatically, allowing for direct

control of flow rate and power,

while keeping the machine’s

efficiency high across a wide range

of flows. The drivetrains’ modular

cassette format makes maintenance

simple, inexpensive, and fast.

Figure 2

Figure 1

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BLADES

BELTS

SHAFTS

GUIDEVANES

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Product linesThe hydroEngine comes in two families, defined

by the orientation of the drivetrain. In the Fully

Flooded hydroEngine (FF), the blades move vertically.

In the Free Jet hydroEngine (FJ), the blades move

horizontally. The FF allows for significant tailwater

variation and utilizes a draft tube. The FJ has a higher

head and flow range and does not require a draft tube.

HydroEngines are currently available for low to

medium head and flows with ratings from 10’s of kW

to over a MW. Please see pages 6 and 7 for details.

Free Jet Fully Flooded

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Side profile Side profile

IsometricIsometric

To calculate the estimated capacity and generation

for a hydroEngine installation, refer to the operating

envelope, head-flow-capacity, and efficiency tables

on our website. Generation output can also be

calculated for multi-engine setups where the desired

plant flow exceeds the design flow for an individual

hydroEngine. We recommend contacting Natel for

an optimized generation output calculation using our

internal model which incorporates more details of

the potential project. Find our project capacity

and generation calculator online at:

www.natelenergy.com/turbines/#proj-calc

Operating range

Project Calculator

CALCULATE

Plant Design Head

m cms %your site flowyour site head

Plant Design Flow

50TE

Capacity Factor? ?

Free Jet Fully Flooded

HEAD

6 - 20 meters

FLOW

1 - 200 cms

POWER

25 - 1,400 kW

HEAD

2 - 6 meters

FLOW

1 - 200 cms

POWER

150 - 500 kW

Enter the design head, design flow, and capacity factor for your project. The project calculator will suggest one possible combination of hydroEngines for your site.

InstallationInstallation options for the hydroEngine expand on

layouts similar to conventional Kaplan and Crossflow

turbines, but with greater flexibility in the civil works

design and opportunities for reduced civil works.

The hydroEngine allows for reduction in civil works

cost because it is not at risk for cavitation. In most

cases the hydroEngine can be situated above the

lower pool, reducing the need for excavation. In

addition, the hydroEngine can be placed in a small

vault, with all control and electrical equipment on

a higher floor, further reducing civil works costs

(figure 4).

The hydroEngine can be integrated into any kind of

low head hydropower setting, including in-conduit,

run-of-river, in-dam, and directly in pipelines.

Where possible, the run-of-river approach is

favored, as it provides inherently more protection

from debris, allows straightforward maintenance,

and has less impact on the main water channel

during construction. For any application except for

in-pipe flows, it is critical to properly design the

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plant trashrack to screen debris, while minimizing

maintenance and head losses. Placing the trashrack

at an angle to the mainstream flow, as illustrated in

Figure 3, can allow most floating debris to passively

bypass the plant. The trashrack can be additionally

protected by an upstream float or boom.

In dam or weir hydroEngine

dam

Over canal hydroEngine

drop

Run of river hydroEngine

drop

Figure 3

Figure 4: Comparing excavation and submergence requirements for Bulb turbines vs. a Natel FF and FJ. The Natel turbines sit above lower pool elevation requiring much less excavation.

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Water-to-wire package

Fully Flooded

Free Jet

PTO options

COMPACT BELT DRIVE

Equipment Included

Hydro-mechanical equipment hydroEngine Intake adapter Inlet nozzle Inlet guidevanes (wicket gates) Hydraulic power unit and pressure supply system Design guidance for outlet or plinth Design guidance for draft tube Speed increaser (gearbox or belt drive) Special assembly tools

Electrical equipment Generator Power Factor Correction (if required, and as specified, by customer) Generator protection relay (as specified by customer) Grid protection relay (as specified by customer)

Instrumentation and control equipment Unit SCADA control system (hardware and software) Integrated Sensors: - hydroEngine shaft speed - Nozzle flow control - Inlet guidevane control - Powertrain health - Generator output - Water levels (upper and lower pools)

BasehydroEngine

FREE JET FULLY FLOODED

BasehydroEngine

Water-to-wirePackage

Water-to-wirePackage

*some system components will change depending on project specifications

Gearbox and direct drive configurations available. Figure 5

Figure 6

Figure 7

Turbine Placement Guidelines

The hydroEngine is delivered to the project site as

a compact unit, fully assembled and factory tested.

In most gravity-head situations (run-of-river or in-

dam), the following guidelines are recommended:

• For the FJ, where desired, machine design allows

for the capture of some head below the turbine.

To accomplish this, the exit of the plinth, or

outlet, must be below plant afterbay water level.

• For the FF, the draft tube outlet must be

submerged at all times of expected operation.

It is recommended to submerge the upper edge

of the draft tube outlet a minimum of 12 inches,

or 1/4 draft tube outlet height, below the lower

pool surface. No draft tube is required for the FJ.

• For both the FJ and the FF machines, the top of

the intake should be submerged below the upper

pool in accordance with best practices to avoid

formation of air vortices.

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Plant safetyControl panel

Natel’s UL listed control panels provide autonomous

turbine or plant level operation through on site or

remote user interfaces. Turbine fault detection and

failsafe design are built in. More advanced condition

monitoring packages are available which can

automatically collect and store frequency spectrum

data from numerous sensors for more detailed

diagnostics. Both the turbine and control system

have extended temperature operation packages for

Flow control

Fully Flooded

The Fully Flooded hydroEngine controls flow

rate using its adjustable guidevanes. If required,

the guidevanes can close to a point almost, but

not completely, reducing the flow rate to zero.

In addition to the internal guidevanes, Natel

recommends installing a separate gate near

the plant intake, capable of dewatering

the entire plant for maintenance purposes.

Free Jet

Free Jet hydroEngines utilize a nozzle to control flow

and create optimum jet shapes across a wide range

of flow conditions. In the case of a grid fault or other

rapid shut down, a jet deflector nearly instantly

redirects flow away from the drivetrain with no

change in plant flow. In figure 8, the jet deflector is

shown on the left in the open position, allowing flow

across the blades. On the right, the jet deflector is

redirecting flow around the drivetrain.

use in cold or semi outdoor conditions. The control

system scales to multiple hydroEngines in a site and

can integrate under an existing plant level controller,

or can optionally handle plant level control of

different bypass gates, intake gates, and trash racks

itself.

The control panel can optionally be fitted with

a touchscreen or serve the HMI to an existing

computer on the local control network.

Runaway/Overspeed Prevention

If the generator is disconnected from the grid while

generating power, it is possible that the hydroEngine

shaft speed will increase up to 2-2.4X normal

operating speed, depending on the guidevane setting

when the runaway initiates. Natel’s control system

will instantly detect the initiation of runaway and

shut down the hydroEngine gracefully.

Eliminating water hammer

In Free Jet hydroEngines, a jet deflector enables

near instant depowering without any water hammer.

Given a grid outage or machine trip event, the jet

deflector diverts 100% of water around the runner

in <1 sec, allowing for full generator depowering

within 3 seconds, with penstock pressures rising less

than 5% over normal static pressures.

Figure 8

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the individual components such as the blades and

guidevanes can be lifted out and moved by one

or two technicians. All heavier components have

multiple forklift and winch lift points.

Natel recommends a combination of routine

(annual) inspection and periodic overhauls. Annual

inspections center around checking sprockets,

bearings, and hydraulic systems. These systems are

designed to last the life of the system. Lubricants

and fluids may need to be replenished. Periodic

overhauls center around replacing the belts and

potentially some bearing seals. These replacements

can be completed quickly and inexpensively and are

planned into the O&M budget.

Annual inspections should include a review of the

cassette (check belt and sprocket condition, check

guidevane bushings, inspect shaft seals), power

takeoff system (check gearbox lubricant level and

Monitoring & MaintenanceMaterials of construction

Submersible components in the hydroEngine are

composed of galvanically compatible, corrosion

resistant materials with high fatigue strength.

For example, most structural components are

manufactured from 304, 316, or 17-4PH stainless

steels.

Debris maintenance and water quality

Large, rigid debris should be passively bypassed

with good plant design, or screened out of the intake

with a trashrack. Abrasive particulates should be

settled prior to the hydroEngine intake. In the event

that debris is entrained within the hydroEngine, the

upstream cascade of guidevanes are kept clean by

an automatic cleaning rake module, which physically

removes any foreign objects which might become

entrained on the leading edges. The moving blades

within the hydroEngine are self-cleaning, as the

blades’ leading edges become their trailing edges

once per revolution. The hydroEngine is capable of

operating in brackish water.

The hydroEngine is designed to accommodate

sediment and debris up to 3/4” diameter. Larger

material is filtered through a standard trash rack

system.

Maintenance

The hydroEngine is an exceptionally easy and

accessible hydroelectric generator. It is designed

from the ground up to be serviceable with common

tools and with basic mechanical skills. The Fully

Flooded model’s cassette can be extracted for

easy access to all the power train components.

The Free Jet model’s cassette can be serviced

simply by opening the housing top and performing

maintenance in situ or after removal. Many of

condition, check any belts, check shaft alignment,

check seals), hydraulic power system, if applicable,

(replace filters, check hoses and fittings for leaks or

other symptoms requiring replacement, check fluid

and replenish or replace as necessary), electrical

equipment (inspect wiring and sensors; ensure

leads, cables, terminations are in good condition),

and balance of plant (inspect flanges for leakage;

inspect fasteners, flow control gates or valves,

inspect all surfaces for fouling and clean or apply

countermeasures as necessary, ensure plant

ingress and egress in good condition, ensure plant

maintenance equipment such as hoists are in good

operating condition).

The main power transmission belts inside the

hydroEngine, along with the wear faces of the main

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shaft seals, are designed for a 15,000 hour life at

full load. For a plant with a 50% capacity factor

and running at full rated head, this works out to

a overhaul interval of about 3.5 years. Moving

components in the hydroEngine are contained in

an easily-removed cassette module. To access the

cassette module, the hydroEngine’s side plates or

cover plate are removed. A chainfall or similar type

of hoist can be utilized to remove the cassette for

maintenance that cannot be performed in-situ.

The hydroEngine is designed for a 20-25 year

project life and beyond with regularly scheduled

maintenance. Maintenance cycle on the belts and

minor parts of the powertrain is every 3 to 5 years,

depending on project capacity factor.

Fish passageFish friendly

In the hydroEngine, due to the low rate of flow

relative to blade speeds, the low overall blade

speeds, and high static pressures, the hydroEngine

can coexist peacefully with fish and other

aquatic organisms. Specifically, the hydroEngine

accommodates downstream fish passage of

anadromous fish smolts. Upstream passage of

spawning adult fish can be accomplished with

conventional fish ladders, at the low head drop

or diversion. Natel is compiling test data on fish

passage to document these advantages.

Watershed friendly

Natel’s low-head hydroEngine enables a new type

of hydropower development designed explicitly for

watershed friendliness, safe fish passage, and for

low environmental footprint. We call this approach

EcoSmartHydro®. Fundamentally, a hydro project is

also a water project, and where appropriate, we work

with clients to design projects for not only impact

mitigation, but also water and ecosystem co-benefit

creation. Water co-benefits that are created range

from distributed groundwater recharge to reduced

stream temperatures; ecosystem co-benefits range

from wetland and fish habitat creation to sediment

management.

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Cavitation

The hydroEngine is not at risk of cavitation when

applied in its normal range of operation. As

described above, this opens up many additional

site layout options. This also improves long term

maintenance and operation and provides good

environmental performance.

Temperature changes

The hydroEngine has been designed to

accommodate a wide range of temperature

fluctuations. Water temperatures can range from

freezing up to 80F (27C) with no deleterious impact

on operations. Plants can be designed for ambient

temperatures as low as -30C (-22F).

Monitoring & SCADA

Natel’s proprietary software analytics platform,

watershedOS, serves as a secure online tool for

managers and owners to remotely monitor system

status and operation metrics of all their hydroEngine

assets. This platform allows for access to real-

time data on plant generation, flow, and plant

health information, and is used to optimize plant

performance and plan for predictive maintenance to

maximize uptime.

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Figure 10

FREE JET

FULLY FLOODED

Figure 11

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Natel Energy2401 Monarch Street

Alameda, CA 94501P: 510.342.5269

info@natelenergy.com

Oakland

Alameda

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