Electro-hydraulic solutions for hydropower, water and wastewater
Resources
The resources page for Sorensen Systems is dedicated to providing valuable insights and solutions for hydropower engineers and designers. Find a curated collection of articles and operational strategies aimed at enhancing your expertise in the field of hydropower. Our articles cover a wide range of topics, from the latest advancements in turbine technology to sustainable design practices. Explore the links below to access in-depth articles and stay at the forefront of hydropower innovation.
Hybrid actuation systems reduce energy consumption and maintenance costs. See why we’re excited about the possibilities of self-contained linear actuation.
Downstream penstock (Mahoning Creek Hydroelectric Project) Mahoning Creek Lake and Dam in Armstrong County, Pennsylvania, USA by Margaret Luzier, U.S. Army Corps of Engineers – U.S. Army Corps of Engineers Digital Visual Library Adjacent to dam (Meldahl Hydroelectric Facility, KY)
Hydropower Hydroelectric power, or hydropower, is a type of power that uses the force of the flowing water to generate electricity. While there are a multitude of different hydroelectric facilities, they all use turbines/generators to convert the kinetic energy of
The engineers at Sorensen Systems are all too familiar with the problems that power plant operators are having with biogas contaminated with siloxane. How can something so seemingly minor destroy turbines (and how can it be mitigated)?
Water is one of the most common contaminants in a fluid power system and one of the most damaging. When water contaminates a system, it can cause serious problems.
Electrohydraulic Actuators for Water Treatment & Hydro Installations
Reducing costs while increasing energy efficiency
We are excited about a newer type of hydraulic actuators with applicability in water/wastewater and hydropower installations. Hybrid Actuator System (HAS), a newly launched product from Parker Hannifin’s cylinder division, is a self-contained linear actuation system that brings electrification to where the work occurs. Here’s the main benefit: By localizing the power source, Parker’s hybrid actuator eliminates the centralized power unit along with its electric motor, pump reservoir, and related valving, but also all the hoses and tubes connecting them to the actuator — dramatically reducing system complexity and simplifying troubleshooting. Instead, it consolidates the entire hydraulic system into a single component integral to the actuator that hooks up to a local control point.
Hydraulic Actuators Offer 3x Power Density of Traditional Systems
Hybrid actuation systems have one-third the footprint of a equivalent hydraulic power unit. Compared to a 10 HP hydraulic power unit, which typically occupies 6.6 cubic feet, the HAS 500 occupies just 1.9 cubic feet. The HAS 500 has a 2-1/2″ bore, 1-3/8″ rod, 24″ stroke 4 GPM operating at 3000 PSI.
Saves energy by deploying incrementally as needed
The horespower losses that occur in valve-operated hydraulic systems are significantly reduced in hybrid actuation systems (HAS). In HAS, 72% of input power is available for work, compared to just 47% availability in a traditional hydraulic systems.
For this reason, energy consumption per cycle is significantly lower in hybrid actuation systems.
Features benefit customer’s application
Designers and integrators who employ hybrid actuation systems help their customers reduce energy costs associated with operating their hydraulic systems. Additionally, the end user will have reduced maintenance costs and hours. The components absent in self-contained actuators (electric motor, pump reservoir, hydraulic lines, fittings) no longer require attention. Parker’s HAS units operate for at least 8,000 hours before maintenance is due.
Will it work for your application?
Please contact us through our secure online form so one of our sales engineers can review your application.
Hydropower Dams: Converting Non-Powered Dams to Generate Hydroelectricity
The benefits of converting non-powered dams to hydropower dams are:
● Reduced installation costs ● Lower levelized cost-of-energy (LCOE) ● Fewer barriers to development ● Less risk within a shorter time frame.
According to the U.S. Department of Energy, of the 80,000 dams registered in the U.S., only 3% produce power. The department claims that 54,391 non-powered dams have the potential to be converted and generate electricity as hydropower dams. This can possibly add 12 GW (12,000 megawatts or MW) of renewable and reliable energy. The additional energy would help local communities across America move towards sustainability. In this article, we will discuss the pros and cons of such a transition, things to consider before converting a non-powered dam, and the ways to do it.
The Benefits of Converting Non-Powered Dams Explained
Upgrading a non-powered dam in most cases is a more cost-effective solution than building a new hydroelectric facility. Firstly, it is less time intensive. The dam owners can maximize the existing infrastructure. Which means they often need fewer permits, less equipment, and experience lower construction costs. Secondly, when we talk about the environmental concerns, there are fewer barriers to the existing development. Finally, refurbishing existing non-powered dams supports local communities by adding jobs that could not be outsourced otherwise. For example, the comprehensive study done by Navigant Consulting Inc. revealed that expanding hydropower potential could create 1.4 million quality jobs.
Small Distributed Hydropower
Fortunately, new technologies make hydropower more accessible for sites with a generating capacity up to 10 MW. The existing small hydropower locations make up about 75% of the current US hydropower fleet in terms of the number of plants. We believe that this number will grow. In order to support the small hydropower industry, the federal government has recently introduced new laws that simplify the permitting requirements for small hydropower facilities and has approved additional funding. As a result, we expect the economic feasibility of developing new small hydropower projects to slowly improve over time. If the trend continues, more and more communities will get access to small, distributed power in the US.
In regards to installation requirements, most small hydropower schemes fit into two main categories: run-of-river systems and integrated into existing water infrastructure, including dams.
Considerations When Converting Non-Powered Dams into a Hydropower Source
Water Availability To analyze the future energy potential of the non-powered dam, start by looking at water availability and physical relief data. For this purpose determine the regional water availability. This can be done by looking at the precipitation (P) and runoff (Q) ratio, also known as Q/P ratio. After you finish your analysis, you will find that the locations with higher latitude and colder climates generally have higher hydropower potential. Unfortunately, high evaporation in warmer climates reduces available runoff making the water resources for hydropower less accessible. Additionally, the high precipitation in humid climates also challenges possible flood operations, making these areas less attractive for development.
Streamflow Streamflow refers to the amount of water flowing in a river. Seasonal changes alter streamflow since precipitation contributes to higher stream flows. Stream gauge monitoring is the most effective way to measure available streamflow. However, many non-powered dams will not have records pre-dating the 2000’s. To estimate the monthly average streamflow, use the formula below:
Streamflow = Drainage Area * Runoff
Please refer to the National Inventory of Dams (NID) database or the National Hydrography Dataset (NHDPlus) for estimating the drainage area. NHDPlus, which geospatially models the flow of water across the United States, provides the cumulative drainage area at the endpoint of most streams. In most cases, the cumulative drainage area of a stream resembles the drainage area of the stream on which a non-powered dam is located.
Hydraulic Head This is the change in vertical height between hydro intake and discharge points. Measure the height difference between headwater and tailwater elevations to get the most accurate hydraulic head measurement if available.
Power Generation and Capacity Take the hydraulic head and monthly average streamflow measurements to calculate the potential generation capacity.
Methods for Converting Non-Powered Dams Into Hydropower Dams
There are hundreds of NPDs with potential capacities greater than 1 MW, which are mapped out below by the US Department of Energy. See the list below:
Downstream penstock (Mahoning Creek Hydroelectric Project)
Mahoning Creek Lake and Dam in Armstrong County, Pennsylvania, USA by Margaret Luzier, U.S. Army Corps of Engineers – U.S. Army Corps of Engineers Digital Visual Library
Adjacent to dam (Meldahl Hydroelectric Facility, KY)
Photo courtesy: Stantec
Downstream of dam (Montgomery Locks and Dam Hydroelectric Project)
Through dam (Robert Moses Niagara Hydroelectric Power Station in Lewiston, NY)
By Busfahrer – taken by me, from Robert Moses Parkway in Niagara County, New York State, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=3941077
In gate (Lower St. Anthony Falls Hydroelectric Project)
In lock (proposed Heidelberg Hydroelectric Project, KY)
Non-Powered Dam (NPD) Locations in the US
Hundreds of NPDs have potential capacities greater than 1 MW, which are mapped out below by the US Department of Energy.
Notably, the three hydrologic regions with the most hydropower potential are Ohio, Upper Mississippi, and Arkansas-White-Red. Given the amount of precipitation and low evaporation ratios, Eastern Ohio, Tennessee, and Pacific Northwest are the most favorable regions for hydropower generation. On the contrary, the Colorado River System and the Rio Grande regions have low Q/P ratio and heavily rely on storage in large reservoirs (like Hoover Dam). Due to limited water availability in these regions, there are fewer hydropower projects to be developed.
Conclusion
Considering that the energy potential at non-powered dams could increase the US hydropower capacity by up to 15% or to 90 GW total, converting non-powered dams is the important step to expanding renewable energy capabilities in the US. Sorensen Systems is here to support the efforts of municipalities switching to renewable energy production.
Hydroelectric power, or hydropower, is a type of power that uses the force of the flowing water to generate electricity. While there are a multitude of different hydroelectric facilities, they all use turbines/generators to convert the kinetic energy of flowing water as it moves downstream into electricity for homes, businesses, and industry. Different types of turbines are used in hydroelectric power plants, and each type has its own advantages and disadvantages.
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Turbines used in hydroelectric power plants fall into two categories: Impulse and Reaction based. Impulse based turbines include Pelton and cross-flow turbines. Reaction based turbines include three subtypes: Francis turbine, propeller turbine (bulb turbine, Straflo turbine, Kaplan turbine types), and kinetic turbine.
As different types of turbines have their pros and cons, we recommend starting your research by answering a few questions below:
What is the “head”? (Head is the vertical height change in water levels between the hydro intake and hydro discharge points.)
What is the volume (flow rate) of the water?
What are the efficiency requirements?
What is the budget?
Types of Turbines: Impulse Turbine vs. Reaction Turbine
The two main differences between impulse and reaction turbines are the number of stages in a turbine and the maximum steam velocity. Impulse turbines capture energy at a single point where the water jet is hitting it; reaction turbines capture energy across the whole wheel at once, which makes them more efficient in producing energy. Therefore, sites with high head and low flow should always consider the impulse turbines over reaction turbines.
In a Pelton turbine pressurized streams of water via nozzles are directed towards a series of spoon-shaped impulse blades, also called buckets, at splitters which divide the water jet into two streams. These streams then flow along the inner curve of the buckets and then leave in the opposite direction they came in.
This creates an impulse on the blades and generates torque and rotation in the turbine. Pelton turbines are generally used at sites with heads greater than 985 feet and have a reservoir of water above.
The cross-flow turbine also called an Ossberger turbine, has a shape of a drum. Its structure is similar to that of a water wheel. When the water enters the turbine at the edge, it moves inward. Then it flows through the runner and exits from the inside back out.
As the water passes the turbine blades twice, it provides additional efficiency in creating power as well as self-cleaning itself of small particles and debris. Due to its shape, the cross-flow turbine is a low-speed machine and is best used for locations with a low head and a high flow.
Reaction Type Turbines
Inward vs. Outward Reaction Turbines
All reaction turbines fall into the inward and outward category based on the water flow direction. If water enters the runner from outwards to inwards, we call the turbine an inward reaction turbine. On the contrary, outward reaction turbines use the water that flows through the runner from inwards to outwards.
Francis Turbine
Sketch of Francis turbine. Jahobr, CC0, via Wikimedia Commons
The Francis turbine is the most popular type of turbine used in hydropower plants and sites with high head applications (130 to 2,000 feet). Moreover, this type of turbine works equally well in both horizontal and vertical orientations. Water enters the Francis Turbine radially and flows inwards toward the center. Once the water has flown through the turbine, it exits axially parallel to the rotational axis. Due to a wide head range and high efficiency, the Francis turbine type became the industry leader in the hydropower world.
High-pressure water enters the Francis turbine through a snail-shell casing called a volute. This lowers the pressure of the water but maintains its speed prior to encountering guide vanes. Consequently, the guide vanes direct the water flow toward the fixed blades of the runner at an optimum angle, causing the water to deflect slightly sideways and axially. Finally, the water exits out to the draft tube and into the tail race. As a result, water contacting the runner blades and being deflected results in a force that pushes the blades in the opposite direction thereby rotating the runner and transferring power from the water to the turbine shaft for electric generation.
Propeller Turbine
The propeller turbine is a variation of inward flow reaction turbine with a runner shaped like a propeller that you see in ships and submarines. It comes with either fixed or adjustable blades. The water flow in the propeller turbine is controlled by adjustable guide vanes (wicket gates). The vanes push the water through the runner and react with the blades. Propeller turbines are commonly used in sites with high flow rates. There are a few types of propeller turbines available on the market, including:
Bulb Turbine
Sketch of Bulb turbine, Jahobr, CC0, via Wikimedia Commons
The bulb turbine is a compact propeller turbine with an upstream watertight casing that contains a generator located on a horizontal axis. The main pro of the bulb turbine is its space-saving design since the turbine and generator form one sealed unit. However, this makes the bulb turbine hard to access for service. It also requires a certain temperature and air circulation conditions.
Straflo Turbine
Sketch of Straflo turbine, Jahobr, CC0, via Wikimedia Commons
The Straflo turbine is a compact propeller turbine with a generator built into the rim of the turbine runner. Thanks to this design, Straflo turbines allow the unit to operate in low-head conditions while keeping most of the generator components out of the water.
Kaplan Turbine
The Kaplan turbine is a propeller turbine with adjustable blades and automatically adjusted wicket gates. It offers users a wide range of head/flow levels. Kaplan turbine is also efficient in the low head/high flow applications which makes it stand out compared to the Francis turbine.
Sketch of Kaplan Turbine, Jahobr, CC0, via Wikimedia Commons
Kaplan turbine from Kraftwerk, GT1976, CC BY-SA 4.0, via Wikimedia Commons
Kinetic Turbine
The kinetic turbine is a free-flow turbine that generates electricity from the kinetic energy of the flowing water as a combination of an efficient axial flow propeller and advanced controls. It uses the natural water stream pathway and does not require any diversion of water through pipes, human made channels, or riverbeds, making it compact in size and easy to install.
Conclusion
Now that you have discovered how different types of turbines used in hydroelectric power plants operate, you may be considering which one to choose for a particular project. Since there are various turbine types to choose from and multiple factors to consider, Sorensen Systems is here to help you. While we do not supply turbines, we partner with turbine manufacturers on hydroelectric installation and refurbishment projects. Our cost-effective turbine-generators and turbine control systems provide reduced maintenance requirements and savings to small hydro sites around the world.
Hydroturbine for small hydroelectric power generation project
Why Siloxane Removal Is Critical
Harmless Food Additives and Cosmetics Are Destroying Million Dollar Turbines
After you enjoy that quick microwave meal or fix your makeup, what you throw in the trash could end up costing you in higher electric bills. First your waste makes it to the landfill. Then someone converts that into biogas to burn at a nearby electric power plant. During this process, siloxane gas found in landfill garbage damages the stainless steel turbine running the electric generators. Believe it or not, something as simple as food or cosmetics has the potential to destroy equipment worth millions of dollars.
While this may seem far-fetched, the engineers at Sorensen Systems are all too familiar with these problems. Power plant operators are struggling with contaminated biogas in some of our more innovative electric plants. In the face of rising costs for petroleum-based fossil fuels, such as coal, oil and gas, the idea of “cheap” biogas has gained popularity as an alternative.
Siloxane Contamination
So what exactly is happening here? Unlike natural gas, gases from landfills are saturated with moisture. They also carry varying quantities of compounds that contain sulfur, chlorine, and silicon. You can see siloxane in biogas in the form of a white powder in gas turbine hot section components. The white powder is primarily silicon dioxide, a product of siloxane combustion. This by-product has been identified as responsible for turbine failures, which has caught the attention of power plant operators. Fortunately, there are efficient and cost-effective ways to remove contaminants such as siloxane.
Siloxane removal systems are the best way for combustion turbine plant operators to reduce the consequences of siloxane contamination in the biogas fuel. The biogas generated in landfills and wastewater digesters contain siloxane – a man-made chemical that changes into silicon dioxide (sand) when combusted. Imagine throwing sand into your car engine! That’s what’s happening here.
Siloxane Removal Systems
When landfill and digester gas are used to fuel turbines, silicon dioxide builds up. This build-up significantly increases maintenance costs, reducing the feasibility of these important green energy projects. A siloxane removal system offers a way to reduce the harmful affects. One tower adsorbs siloxane using a specialized blended media and the other tower regenerates. This exhaustes the collected siloxane to a flare or thermal oxidizer. In combination with advanced chilling systems and improved filtration, power plant operators have reason to believe that a solution exists for combating siloxane contamination.
Water Contamination In Hydraulic Oil
Portable Purification Systems Solve Contamination Problems in Power Plants
Hydraulic oil or hydraulic fluid is the mechanism for transferring power in hydropower systems. These fluids can be water or oil-based. In order for these power systems to function properly, the system must be free of contaminants.
Water is one of the most common contaminants in a fluid power system and one of the most damaging. When water contaminates a system, it can cause serious problems. Among the most serious problems are:
Fluid breakdown
Reduction of lubricating properties
Additive precipitation
Oil oxidation
Abrasive wear
Corrosion
There are a variety of so-called dryers that attempt to address the water contamination issue. A centrifuge unit can remove water. However, there are some drawbacks. These include it only removes free water, has difficulty breaking stable emulsions, and is costly. Another type of dryer is a desiccant unit. Unfortunately, they have limited water removal capability, they only remove air ingressed particles, and again, can be costly. A third option is a coalescent unit. Which can only remove free water, has difficulty breaking down stable emulsions and can take up a lot of floor space.
Free vs. Dissolved Water
When discussing the effects of water contamination, there are two kinds of water to consider. The first is so-called “free” water and the second is “dissolved.” Free water occurs when oil becomes saturated and cannot hold any more water. This water is usually seen as cloudy oil or puddles of water at the bottom of an oil reservoir. Water which is absorbed into the oil is called dissolved water. At higher temperatures, oil has the ability to hold more water in the dissolved stage due to the expansion of oil molecules. As the oil cools, this ability reverses and free water will appear where not visible before. In addition to temperature, fluid type also determines the saturation point for each system.
Restoring Contaminated Hydraulic Oil
With the use of a portable purification system from Parker, it’s possible to restore the oil to acceptable levels of purity. The machine draws the contaminated oil via a vacuum. The oil passes through the in-line low watt density heater. The heater raises the oil’s temperature an optimal 150°F. The oil then enters the distillation column where it is exposed to the vacuum through the use of special dispersal elements.
This process increases the exposed surface area of the oil and converts the water to vapor form. The vapor form is then drawn through the condenser by the vacuum pump. The water-free oil falls to the bottom of the column and is removed by a heavy duty lube oil pump. This pump forces the dry oil through a final particulate removal filter. Clean oil passes out of the unit, back to the reservoir, and into the system. The oil is clean.
Parker Sentinel System
The Parker Sentinel System has many applications in the commercial/industrial marketplace. The most common applications in power plants are turbine oil, transformer oil and electro-hydraulic control systems. The system has many important design advantages:
Condensate holding tank to eliminate potential hazard of exhausting in the atmosphere
Compact size allows for easy transport and movement around the plant
Automatic operation increases running time and reduces labor costs
High temperature safety circuit prevents system damage
Programmable thermostat allows for unattended operation and increases oil life
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