Environmental solutions in hydropower machines

1Environmental solutions in hydro power machines | Schuol | 2011-12-07

Environmental solutions in hydro power machinesJürgen Schuol, Jason Foust, Daniel Christ

Phnom Penh, 2011-12-07


Voith Group and Voith Hydro Group Division

• Voith: family-owned from its onset in 1867

– Four divisions: Hydro, Paper, Turbo, and Industrial Services

– Worldwide presence for our customers (> 50 countries)

– FY 2009/10: Sales 5,191 Mio. €, Employees 39,132

• Voith Hydro: products and services of large and small hydro plants - turbines, generators, pumps and automation

Itaipu (Brazil) Three Gorges, San Xia (China)Kops II (Austria) Revelstoke (USA)


Hydro PowerSuccesses in Sustainability

We support the development of hydro power with a keen sense of responsibility, environmentally and socially.

Example: Hydropower Sustainability Assessment Protocol• Performance assessment tool• to produce a sustainability profile• for all types of hydro power projects • in four major life cycle stages

http://www.hydrosustainability.org/


Sustainability Topics


Fish Friendly Turbines

Bonneville Dam (USA)


Overview of damage mechanisms for fish

Third option (after spilling and fish collection) is to allow fish to pass through

turbines.


Fish Passage Development

In the early 1990’s, the US Department of Energy launched the

Advanced Hydro Turbine System (AHTS) program.

The program was subdivided into two main areas of focus:

- larger axial flow applications

- smaller radial flow applications

Conventional Radial

Conventional Axial


Reference Minimum Gap Runner (MGR):e.g. Bonneville – USA

The project includes replacement Kaplan turbines designed to enhance fish survival.

MGR DesignExisting Design


Alden Turbine Development

Turbine runner• Larger to meet fish passage

criteria (shear, min pressure, pressure change rates)

• Slower rotational speed and reduced number of turbine blades

• 6” diameter nose thickness

Distributor• Optimized stay vane to wicket gate

alignment to minimize gap • Reduced number of stay vanes

and wicket gates to minimize strike

Expected fish survival > 98%~13 mm gap


Fish Survivability

• Graph shows survivability considering blade strike for an ~20 cm fish

• Survivability rates assume all turbines can meet secondary fish survivability criteria (minimum pressures, pressure change rate, shear)

Power, [MW]

MGR

Alden Runner

Head, [m]


Auto-Venting Turbines

Conowingo Dam (USA)


Turbine Aeration for Water Quality Enhancement: Motivation

• Warmer temperatures can cause thermal stratification

• Reservoir separates into layers, preventing natural mixing

• Low dissolved oxygen (DO) levels in turbine discharges can harm fish and other aquatic life


Overview of Aeration Techniques: Auto-Venting Turbines (AVT)

In order to improve tailrace dissolved oxygen levels, air or oxygen gas can be introduced into the water passing through turbine.

3 primary AVT methods:

• Central aeration (blue) – air injected through deflector

• Peripheral (yellow) – air injected through continuous slot in discharge ring

• Distributed aeration (green) – air injected through hollow blade


Turbine Aeration for Water Quality Enhancement: Conclusions

Distributed aeration is most effective for 0.8 ≤ Q/Qopt ≤ 1.2

• largest potential for air flow and DO uptake

• lowest impact on turbine efficiency

If distributed not available, peripheral next alternative

• for Q/Qopt ≥ 0.8, air flows, DO uptakes and efficiency impacts more favorable than central

Central aeration third choice

• effective for Q/Qopt < 0.8

AVT combinations can be used to maximize uptake while minimizing performance impacts


Protective CoatingSystems


In hydro power plants located on rivers originating from mountainous regions (e.g. Mekong), hydro-abrasive erosion is a known phenomenon, but often lack of awareness!


Hydro-abrasive Erosion: Risks and Solutions

Hydro-abrasive erosion increases the economical risk of a hydro power project due to:

• Maintenance and repairs at short intervals

• Loss of efficiency

• Loss of productive time

Different approaches for sediment management:

• Civil works (e.g. desilting chambers, flushing facilities)

• Constructive means (e.g. type of machine, speed, hydraulic layout)

• Protective coatings


Protective coatings

Diaturb 532 Softurb 80

Hard Coating

• Carbides in a metallic matrix (WC + Co/Cr)

• Application by HVOF process

Soft Coating

• Polyurethane based

• Application by painting or spraying


Voith Hydro Coating SystemsCombined Approach

Diaturb 532(Hard

coating)

Softurb 80(Soft

coating)- Wearing rings (F)- Facing plates (F, K)- Guide vane end sides (F, K)- Guide vane closing edges (F, K)- Pelton equipment

- Narrow Francis water passages- Coatings applied on site

- Runners (F, K)- Guide vanes (F, K)- Other (e.g. shaft)

F ... FrancisK ... Kaplan

Combination

Partial hard coating

Soft coating on top


Summary


Possible Sustainability Profile - without and with Voith Hydro environmental solutions

Level 3: basic good practice

Level 5: proven best-practice


Contact:Dr. Jürgen SchuolManager Environmental EngineeringVoith Hydro Holding GmbH & Co. KGTel. +49 7321 37 [email protected]

Environmental solutions in hydropower machines

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