Most of us are aware that bearings are important components used in various mechanical setups, vehicles, household appliances, and more. However, bearings are also proving to be an integral part of new and modern products like electric vehicles (EV), drones, UAVs, robotic surgery systems, and more. Additionally, bearings are also playing a key role in hydro and solar power systems enabling smooth, efficient, and long-lasting operation of mechanical components.
Given the rising demand for electricity, the push towards sustainability, and the increased demand for cleaner sources of energy the demand for hydro and solar power is rising. According to Niti Aayog, there are 198 hydropower plants and 849 small hydropower plants in India. Also, there are 363 solar power projects producing a total of 107945.61 MW of electricity.
Source Wise Energy Generation
The energy generation from these renewable sources systems is influenced by various factors like rotors, blades, gearboxes, sealing systems, bearings, and more. Bearings are the overlooked components but are quite crucial for the smooth and reliable running of these setups.
Renewable energy systems are fitted with various types of bearings including ball bearings, tapered roller bearings, plain bearings, self-aligning bearings, slewing bearings, and more. These bearings are used to support the rotating parts, reduce friction, and ensure sufficient power transmission. When it comes to the solar energy system, bearings are widely utilised in solar trackers, gearboxes, actuators, pivot joints, and more, while in hydropower systems bearings are fitted in turbine shafts, generator rotor, flow control mechanisms, and more.
| Source | Percentage |
| Coal | 74.58% |
| Hydro | 6.17% |
| Nuclear | 3.11% |
| Oil & Gas | 2.05% |
| Small Hydro | 0.24% |
| Solar | 9.61% |
| Wind | 3.91% |
| Bio Power | 0.33% |
Overview of Hydro and Solar Power Systems
Solar power as the name implies works by converting energy from the sun into power. Energy generated through the sun is of two types i.e. electricity and heat. Solar energy is a clean source of energy and has no harmful emissions, whereas hydropower generates energy from the flow of water which spins the turbine which is connected to a generator, the turbine’s motor further rotates the generator’s motor creating electricity.
Hydropower in India currently accounts for 6-7 % of total energy generation. Both of the sources i.e. solar & hydro, are vast global resources and have existed for centuries, but in recent years the majority of nations across the world are finding new ways to adapt them to work and cater to the increasing energy needs. For years National Bearing Company (NBC) has been supplying precisely engineered bearing solutions for numerous hydro and solar power systems.
When it comes to comparing these energy sources, it’s hard to say that one is definitely better than the other. It really depends on factors like how much sunlight an area gets and whether there are large bodies of water nearby. So, what works best for one location might not be the right fit for another.
Bearings in Hydro Power Applications
Power or electricity is generated in hydropower plants when the flowing water turns hydroelectric turbines. These turbines use the kinetic energy of water to generate mechanical energy. These turbines work under constant stress due to the continuous flow of water, thus requiring regular maintenance. These turbines to rotate smoothly and reduce friction are fitted with bearings. Bearings in these hydropower setups are under continuous operation and work under challenging conditions, like underwater operation, exposure to debris or rocks, etc.
Types of Bearings Used in Hydro Power Application
- Thrust Bearing: Thrust bearings are widely used in hydropower applications, particularly in turbine shafts. Given their high axial load capacity and long operational life, these bearings are preferred for supporting the weight of the turbine and generator rotors.
- Self-Lubricating Bearing: Self-lubricating bearings are preferred for moving parts in wet environments. Specialities of these bearings are they are maintenance-free, wear & corrosion-resistant, and they work well under static loads. These bearings are used in guide vane pivots, spillways, dam gates, and more.
- Guide Bearing: Guide bearing or radial bearing supports radial loads and allows for the shaft to stay aligned. Such bearings are used in turbine and generator shafts.
- Spherical Roller Bearing: Spherical roller bearings are preferred for their ability to handle radial and axial loads. These bearings have high load capacity, and self-aligning capability, and work fine under heavy loads. This type of bearing is used in the shaft line system, generator rotor, and more.
- Hydrodynamic Bearing: Also referred to as water-lubricated bearing, these bearings use water as a lubricant instead of oil or grease. Hydrodynamic bearings are commonly fixed in submerged shafts and turbines.
Bearings used in these setups are required to be extremely durable and precisely engineered as hydro turbines are constantly moving leading to increased friction, heat buildup, lubrication issues, and stress from external forces like wind, rain, snow, etc. Bearings in hydropower setups are extremely crucial components as the entire operation depends on their functioning. Bearings fitted in these systems are designed to handle high-pressure and heavy loads. Self-lubricating bearings, thrust bearings, spherical roller bearings, cylindrical roller bearings, etc are used in hydropower applications.
Bearings in Solar Power Applications
The increasing awareness about clean energy has led to an increased demand for solar power energy. Solar power setups are made of various components and to enable smooth movement of these components bearings are employed. Bearings are used in solar trackers, motors, gearboxes, and more and allow for the panels to follow the sun and maintain optimal energy generation throughout the day. Various types of bearings including slewing bearings, tapered roller bearings, plain bearings, deep groove ball bearings, and cylindrical roller bearings are used in solar power applications.
The bearings fitted in solar power setups are required to be highly reliable due to the risk of corrosion, exposure to dusty and high-temperature environments, and more. NBC bearings are precisely engineered for solar power applications and have several advantages including, UV resistance, long service life, insensitive to dirt and dust, quieter operation, and more.
Types of Bearings Used in Solar Power Application
- Slewing Bearing: Slewing bearings are the most common type of bearing fitted in main routine joints in solar trackers. These bearings are designed to handle axial, radial, and moment loads and are very durable to handle outdoor environments.
- Tapered Roller Bearing: Tracker drive, pivot mechanism, etc are equipped with tapered roller bearings. These bearings are preferred due to their ability to handle combined radial and axial loads.
- Plain Bearing: To support simple pivot or sliding motion in structural joints, plain bearings are often used.
- Cylindrical Roller Bearing: Cylindrical roller bearings are used to handle radial loads in gearboxes and support shafts. Such bearings are used in tracker drives, power transmission, and more.
- Deep Groove Ball Bearing: Deep groove ball bearings are preferred for electric drives, gearbox assemblies, and more. Such bearings are good for high-speed performance, and quiet operation, and are compact.
Challenges in Renewable Energy Applications
Bearings in renewable energy applications face various challenges, including:
- Harsh Environmental Conditions: Bearings used in renewable energy setups operate under harsh environmental conditions like exposure to water, humidity, dust, sand, UV radiation, extreme temperatures, and more which can result in corrosion, rust, seal failure, abrasion, wear, and more affecting the overall operation
- High Loads & Intermittent Operations: Renewable energy setups are heavy and put intense weight on bearings used, i.e. turbine shafts, solar panels, etc. Additionally, these bearings often experience a lot of starting and stopping during operation due to the fluctuating energy inputs from sunlight or water flow.
- Reliability & Longevity: Reliability & longevity of any bearing are influenced by maintenance, though in renewable energy setups bearings are often located in inaccessible or remote sites which makes periodic maintenance difficult resulting in premature failure.
- Lubrication Issues: This is also one of the key challenges in these renewable setups. Given the remote location and their exposure to harsh conditions, lubrication can quickly degrade which may lead to premature failure.
How to Select the Right Bearing?
Selecting the right bearing for renewable energy applications is crucial as it helps ensure long-term performance, reliability, and more. Some of the key factors to consider include:
|
Factor |
What to Consider? |
|
Load Type & Direction |
Consider the load type, i.e. axial, radial, combined or variable loads. |
|
Operational Speed |
Analyse the speed requirement, opt for ball or roller bearing for high speed & sleeve bearings for low speed. |
|
Environmental Exposure |
Identify the operating environment & possible exposure like water, dust, UV rays, temperature changes, etc. |
|
Lubrication Method |
Select bearings based on lubrication requirements, i.e. self lubricated, oil lubricated, water lubricated, etc. |
Conclusion
Bearings play a vital role in hydro and solar power systems, acting as essential components that boost the overall efficiency of operations. These bearings operate in tough conditions, so it’s crucial that they are of the highest quality. NBC bearings are accurately designed and recognised worldwide for their reliability and excellence. It’s also important to choose the right bearing for your specific application, you can reach out to an NBC application engineer to ensure you make the best selection for your renewable energy needs.
FAQ's
What type of bearing is used in a hydro turbine?
Thrust bearings or plain bearings are most commonly used in a hydro turbine.
What type of bearing is used in a power plant?
What is a turbine bearing?
Turbine bearings are bearings fitted in turbines of hydropower plants. Turbines are fitted with thrust or plain bearings.
