the hydroengine - natel energy · power 150 - 500 kw enter the design head, ... it is critical to...
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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
Oakland
Alameda
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