Turbines for hydropower plants

A water turbine is a turbine which makes the hydropower available. The energy of the water is converted into rotational energy by means of the water turbine, which causes rotation of the turbine shaft. This rotation is used to drive a generator to produce electrical energy. To achieve optimum efficiency, the turbine must be adapted to the specific demands of the hydropower plant such as different heads and flow rates.

ANDRITZ Hydro provides a wide variety of different turbine types - from Pelton turbines for high head applications and large output over Francis turbines for the medium net head range and large output up to 800 MW per unit to Kaplan turbines for low head operation with small unit output. For very low head and low unit output ANDRITZ Hydro offers also bulb turbines.

ANDRITZ Hydro is known for technology applications for special purpose such as pump turbines or tidal current turbines, generating power from water speeds.

ANDRITZ Hydro is famous for its very own invention – the HYDROMATRIX – for low head operations up to 19m that can be installed in existing dams and gate structures.

Bulb turbines

The solution for very low head and low output

ANDRITZ Hydro is the worldwide leader in bulb turbine units with a total installed capacity of approximately 6,500 MW, covering a market share of more than 70%.

Nowadays, very low heads can be used for power generation in a way that is economically feasible. So far, ANDRITZ Hydro has supplied more than 300 units, ranging from heads from 0.5 m up to 30 m, with a maximum runner diameter of 7,700 mm and outputs up to 76.5 MW.

The most important feature of a bulb turbine is the horizontal positioning of the shaft, which results in a reduced size compared to a vertical shaft arrangement.

After the intake, the water passes through the moveable wicket gates, which are another device besides the runner for adjusting the water discharge and, as a result, the turbine output. Levers and links connect the wicket gates to the regulating ring, which is moved by two double acting servomotors. After passing the runner, the water exits from the turbine through the draft tube.

The generator is located in a watertight housing called the “bulb”.

For hydropower stations with very low heads, it is sometimes more economical to use a pit turbine/generator concept by ANDRITZ Hydro. A step-up gearbox increases the speed of the generator to make this component more compact and, therefore, less expensive. This increases the feasibility of these projects. ANDRITZ Hydro teams have extensive experience in bulb turbine technology.

Francis turbines

The ideal choiice for medium head and large unit output.

ANDRITZ Hydro Francis turbines are available in varying configurations, horizontal or vertical, with flexibility in design to ensure best efficiency and reliability of operation under the most extreme conditions.

ANDRITZ Hydro Francis turbines are characterized by incomparable longevity, durability, reliability, and robustness. Extensive research and development activities ensure best efficiency and maximum output, feasible over a wide range of operation, both in multiple and single unit configurations.

ANDRITZ Hydro Francis turbines are ideally suited for energy applications with a medium head of up to 700m and an output of up to 800 MW per unit. It has a very high degree of efficiency of more than 96 % and is an ubiquitously applicable turbine type.

The ANDRITZ Hydro Francis turbine is available as a stand-alone unit with integrated shut-off ring gate, separate upstream butterfly valve, or spherical valve with an excellent operational life cycle.

Kaplan turbines

The solution for low head and medium output

ANDRITZ Hydro has installed about 3,200 Kaplan units worldwide with a total installed capacity of approximately 50,000 MW.

The ANDRITZ Hydro Kaplan turbine is utilized on a low head application with up to 90 m and a unit output of up to more than 230 MW. The degree of efficiency is very high with more than 95 %.
The Kaplan turbine is a propeller type water turbine with 4 to 7 adjustable blades. It is an outward reaction turbine, resulting in a changed water pressure as the water moves through the turbine and gives up its energy.

The runner consists of the stainless steel runner blades mounted on the runner hub and the runner cap at the lower side of the hub, enhancing the optimized hydraulic shape. ANDRITZ Hydro has experience with runner diameters up to 10,000 mm. The runner blades are moveable, allowing to adjust the water discharge and turbine output. Due to these moveable blades, the Kaplan turbines show a high efficiency level. In some applications, where a more or less constant water flow can be guaranteed, the Kaplan turbine can be designed with fixed runner blades.

The ANDRITZ Hydro Kaplan turbine is often used for run-of-river projects, thus recent design development has been geared towards environmental topics – e.g. the oil-free hub, where the runner hub oil is replaced by water.

Pelton turbines

ANDRITZ Hydro Pelton turbine the solution for high heads

ANDRITZ Hydro has supplied more than 1,300 large Pelton turbines with a total capacity of approx. 65,000 MW worldwide.

The Pelton wheel is an impulse type water turbine, extracting energy from the impulse of the moving water. The water is directed with high speed through nozzles against the buckets, arranged around the circumferential rim of a drive wheel – the runner. The shaft design can be either in horizontal position in combination with one or two nozzles per runner, or in vertical position with up to six nozzles per runner.

ANDRITZ Hydro Pelton turbines are used on high head applications of up to 1,800 m and a unit output of up to more than 400 MW. It is mostly installed in storage power plants, has a degree of efficiency of more than 92 % and is almost not susceptible to cavitation.

ANDRITZ Hydro has invented various manufacturing methods for Pelton runners - tailor-made to meet the customers’ needs.

• Fully forged: The buckets are manufactured out of the runner disk.
• HIWELDTM: Cast or forged bucket parts are welded onto the disk.
• MicroGussTM: The buckets are overlay-welded onto the forged disk.

Pump turbines

Best solution for pump storage hydropower plants

ANDRITZ Hydro pump turbines are able to reverse the water flow and operate as a pump to fill a higher located reservoir in off-peak periods and then revert to a classical water turbine for power generation during peak demand.

ANDRITZ Hydro provides the technology and proven expertise in design, manufacturing, supply, installation, commissioning and service of complex pump turbines, mostly based on the Francis turbine design. The multitude of configurations available include horizontal or vertical, single or multiple stage, fixed or variable speed, with or without cylindrical ring gate, and individual or combined actuation of guide vanes, all custom designed and built to meet the most demanding customer requirements and environmental criteria in pump storage applications worldwide.

Unique in their dual mode of operation, ANDRITZ Hydro pump turbines with their ability to master rapid mode changes are ideally suited for generation as well as storage of energy, predestined to stabilize electrical grid fluctuations.

ANDRITZ Hydro pump turbines are characterized by their incomparable performance and the highest of standards.

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