Customisable applications solve specialised problems faced by hydro power plants

Customisable applications solve specialised problems faced by hydro power plants

Through the Hydro and Industrial Services offerings, Wärtsilä is able to offer customised applications to solve the unique and specific problems faced by hydro power plants. While the solutions may vary plant-to-plant, the end result is always increased efficiency, decreased turbine downtime, and increased environmental sustainability.

Text: Harald Brodmann Photo: Wärtsilä

The world is changing rapidly. Populations are growing and consuming more and more energy and demanding clean, renewable, and reliable sources of energy. Nations are working hard to reduce their carbon and environmental footprints, and global agreements require greenhouse gas emission reductions and cleaner technology that reduces the threat to the environment.

The Hydro and Industrial services provided by Wärtsilä help to meet these demands in a truly competitive way. Wärtsilä serves as an independent service and product supplier to the hydro and industrial market. On the industrial side of the offering, Wärtsilä provides standardized seals and bearings to the original equipment manufacturers. The products provided for the hydro market, however, are customized applications for the specific needs of the hydro power plants. The products are not standardized, nor are they tied to any specific brand of equipment, meaning that the service is flexible, customisable, and available to any type of customer with any type of problem.

The technology and materials used are state of the art and backed by decades of industry experience – Wärtsilä boasts 125 years of experience for bearings and more than 30 years of experience for seals. Wärtsilä also has the ability to test and validate applications and systems on our own rigs, giving customers the opportunity to witness the solutions. And as a truly global company, Wärtsilä is able to offer fast and reliable technical service regardless of where the plant is located.

Another big advantage that Wärtsilä offers is a package deal of water lubricated seals and bearings and a water quality system, something that few, if any, of our competitors offer. Beyond the convenience of being able to buy several products as a package rather than as separate products, the superior technology and quality of service provided by Wärtsilä ensures that any downtime in energy production is minimised. This includes downtime due to scheduled maintenance breaks. The water lubricated seals and bearings offered by Wärtsilä are available as composite units – that is, they are offered as a single system rather than two separate products. They are very lightweight and do not require any lifting equipment in order to install. This makes the process very fast and easy and requires little downtime for the turbine while the systems are put in place. Wärtsilä’s extremely high operational reliability in water lubricated seal and bearing system also minimises risk of unexpected downtime due to equipment failure. This is why the Loup River Public Power District chose to refurbish and install this technology in their hydro power turbines. Figure 1.

Fig. 1 - Wärtsilä REsafe/Pumpsafe unique water lubricated composite bearing, with composite overwind housing and integral flange.
Fig. 1 - Wärtsilä REsafe/Pumpsafe unique water lubricated composite bearing, with composite overwind housing and integral flange.

 

Conversion of oil to water lubricating technology at Loup River hydro power plant

During 2016 and 2017, Wärtsilä will refurbish three turbines at the Monroe Powerhouse of the Loup River Public Power District in Nebraska, US, by replacing all the oil lubricated seals and bearings with water lubricated seals and bearings. In recent years, the plant has suffered numerous losses due to equipment failure and outages. In oil lubricated systems, if the seal fails and water enters the system, the lubricating property of the oil is lost and the bearing is damaged, or in some cases, destroyed. The result is that the turbine must be shut down until the seal and bearing can be either replaced or repaired. This is a huge monetary loss, as a large hydro power plant (producing 100-800 MW/unit) can sell about EUR 100,000 of electricity per day.

In water lubricated seal and bearing systems, this is not a problem, as oil is removed from the system entirely. Additionally, water is a free and renewable source of lubricant that requires little to no maintenance and poses no threat of environmental damage. Oil lubricated systems, on the other hand, are limited by the life of the oil (about 1-2 years), after which the turbines must undergo maintenance to replace the oil. Oil changes require stopping and maintaining the units, which results in a reduction of production time. Additionally, as these seals and bearings are located at the interface between the environment and the hydro power turbine, an oil lubricated system poses a constant threat to the environment in the form of an oil leak into local water.

The lubricating water for the water lubricated seal and bearing systems is pulled from a local water source. In the case of the Loup River Power Plant, the only feasible water source is the Loup River, which is quite dirty. Clean water is a must in order for the seals and bearings to maintain proper functioning. If dirty water containing a high sediment load is used as a lubricant, dirt and other particles will be pulled into the bearings along with the water. This will cause many problems, including damaged and destroyed seals and bearings and turbine shutdowns.

Wärtsilä’s water quality system (WQS) solves this problem and will be installed at the Loup River Power Plant. This system will clean the water prior to it being used as a lubricant and provide the optimum water quality conditions needed for the seals and bearings to function properly. This will reduce wear and tear on the seals and bearings, prevent dirt from entering the system, prolong the time needed between maintenance checks, increase the lifespan of the seals and bearings, and increase overall efficiency of the hydro power plant. Figure 2.

Fig. 2 - Wärtsilä’s water quality system. This system cleans the water prior to its use as a lubricant in the seals and bearings, enabling the use of dirty water as the water source.
Fig. 2 - Wärtsilä’s water quality system. This system cleans the water prior to its use as a lubricant in the seals and bearings, enabling the use of dirty water as the water source.

 

Automation technology to increase the lifespan of seals and bearings

At the Allen E. Inman powerhouse located at the US Bureau of Reclamation’s Minidoka hydropower plant, Wärtsilä will implement another life-span increasing technology in the refurbishment of two horizontal turbine runners on Kaplan turbines. Working with GE Renewable Energy, Wärtsilä will supply its REvolution system, which offers water lubricated mechanical face seals with a pressurised fluid film between the seal interfaces and a digital control system to optimise performance and manage the lifecycle of the seal. This state of the art, digital technology will fully automate and regulate the amount and pressure of the water entering the system. This system allows Wärtsilä to monitor the health of the equipment in real time and also allows maintenance to be planned well in advance.

Furthermore, the system fully regulates and corrects its own parameters, changing its operating profile to meet the changing demands of the turbine in which it is installed. In the current system, the amount and pressure of the water entering the system is constant no matter what the conditions. The new Wärtsilä REvolution system will match the conditions inside the plant with the environmental conditions outside the plant so that the seals are always operating at optimal conditions. This maximises the life of the system and the time between overhauls of the shaft seals. It will also increase the efficiency of the plant by reducing leakage and debris entering the seal interfaces, thereby reducing downtime at the plant. The monitoring capabilities of the Wärtsilä REvolution digital control system will allow for remote operation of the plant as well as remote monitoring the state of the equipment. This reduces the number of personnel required onsite while making it possible to detect and correct problems before they result in a plant shutdown. Figure 3.

The Wärtsilä REvolution system utilises a REguard or Pumpguard mechanical face seal
Fig. 3 - The Wärtsilä REvolution system utilises a REguard or Pumpguard mechanical face seal, a pressurised fluid film between the seal interfaces and a digital control system to optimise performance, shown here with the interface injection ports (top right), thermocouple (top left) and proximity sensor (top centre).

 

Conclusion

Wärtsilä’s Hydro and Industrial Service offerings are highly customizable applications that can greatly increase the reliability, efficiency, and lifespan of a hydro power plant while ensuring that environmental standards are not only met but surpassed.

Wärtsilä’s long history in marine and hydro solutions and its standing as a global company enables it to offer specialized solutions to meet the specific needs of individual hydro power plants. While the specific benefits that each plant receives from Wärtsilä’s specialized solutions may differ slightly, all hydro power plants can expect to increase their energy output with a superior technology that has been proven to lessen the number of days that a plant experiences downtown due to equipment failure.

The water lubricated seal and bearing systems also reduce the amount of oil used in the hydro power plants, reducing the overall costs as well as the risk of environmental contamination.

From the perspective of the final end user of the electricity – the public – this also increases the positive publicity for hydro power plants. People want clean and renewable energy without sacrificing reliability or quantity, and Wärtsilä has a proven solution to meet these demands.

	The US Bureau of Reclamation’s Minidoka hydropower plant in Idaho, USA, where Wärtsilä is participating in the refurbishment programme. Photo: The US Bureau of Reclamation.
The US Bureau of Reclamation’s Minidoka hydropower plant in Idaho, USA, where Wärtsilä is participating in the refurbishment programme. Photo: The US Bureau of Reclamation.

 

Further Reading:

Light and power for Africa

The end of the line

Bringing clean power to the Caribbean

The modern magician

Author: Harald Brodmann, General Manager, Hydro and Industrial Services, Email: harald.brodmann@wartsila.com

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