Similar Steam Turbine Design
DongFang has successfully developed a new generation of steam turbine, the parameters reach 35MPa/ 615℃/ 630℃/630℃, heat consumption is lower than 6,800 kJ/ kWh and the generating efficiency of power plant exceeds 50%. The goal is to reach 650℃ and 700℃.’
The article contains excerpts from the paper, “The technology development of high efficiency steam turbine” by Dong Fang engineers presented at the 2017 ASME Turbo Expo conference.
The 13th Five Year Plan has targeted the improvement of the efficiency of the existing coal power plants. As per the plan, the coal consumption of active coal-fired power generating units which would be upgraded must be lower than an average of 310 g/ kWh; the coal consumption of 600MW or more in active service (except air cooling units) which would be transformed is demanded to be lower than an average of 300 g/ kwh after 2020. For the newly built power plant, the power supply coal consumption of 1000MW turbine is not higher than 282(wet cooling), 299 (air cooling) g/ kwh, and for unit of 600MW the parameter is not higher than 285(wet cooling), 302 (air cooling) g/ kwh.
In the next ten years, it is expected that the following units will become the new direction of the development of steam turbine technology —  620℃ level of high-power double-reheat unit; 620℃ level low back pressure power unit; 630℃ level steam turbine technology; 650℃ level steam turbine technology; 700℃ level steam turbine technology.
By strengthening reheat, the efficiency of the coal-fired units can be improved. The efficiency of the double-reheat unit can increase about 2% than single-reheat units.
After the technology of 600℃ supercritical power generation is mature, many countries have started the advanced ultra-supercritical power generation technology research project of 700 ℃. Ni-based materials are envisaged for 650℃, although the 700℃.
The development of steam turbine technology has been closely related to the material. The steam parameters of the unit largely depend on material development. DongFang has the capacity of self casting cylinders and valves with the material ZG12Cr9Mo1Co1NiVNbNB. Up to now DongFang has produced the valves and cylinders more than 200 pieces with total weight up to 1140 ton. The heavy forging use material 9Cr-3Co-3W-B which is developed by JSW (Japan Steel Works) for 630℃.
In the case of certain parameters and boundary conditions, a better thermal system can bring the unit higher efficiency. This unit adopts the T-turbine scheme which is proposed in the 700℃ power plant. The scheme can greatly reduce the temperature of all the heat recovery steam extraction and the manufacturing cost and pipe cost, which improves the safety and reliability of the unit as well.

Similar Steam Turbine Design

The system brings the following advantages:  The volume flow of reheating steam was reduced by 35%.The cost of the first/second heating pipeline was obviously declined, and the safety and reliability increases;  The high pressure module of steam turbine has no steam extraction, which increase the efficiency and decrease obviously the stress of rotor.  The system can reduce the initial investment without setting the steam cooler; the inlet temperature of the heater can be reduced significantly; after the reduction of the flow rate, the geometric size of the high pressure module of the steam turbine is decreased. Although the system has many advantages, but also make the system more complex. Control and adjustment of variable working conditions for the system needs further research and actual running test.
Because of the high pressure, DongFang has developed a new type cylinder which was named double-barrel-cylinder. The upper and lower half of the inner casings are set together by seven rings
With ring hoop the cylinder, the inner casing has better air tightness. This structure has been successfully put into operation in the many projects of DongFang, such as Anyuan (31MPa), Wanzhou (28MPa). Because the main steam pressure is increased to 35MPa, the geometric size of the cylinder is smaller and more secure. Inner cylinder shares most of the pressure, about 22MPa, the outer cylinder only to withstand the exhaust pressure of 13MPa. The studs of outer cylinder works in lower temperature and lower stress level, which improves the safety after long-term operation.
DongFang has been using radial-flow stator design to reduce the rotor temperature. With this design, the actual working temperature of the rotor is lower than 620℃.
The loss of the flow path in the steam turbine mainly derives from the loss of type, end loss, steam leakage and other aspects, especially the VHP (HP) module. The secondary loss and leakage of steam loss accounted for the main part. DongFang has developed a new highly after-loaded stator profile. For stages with large blade aspect ratio, DongFang has developed and applied highly frontal loaded stator profile. The secondary loss does not dominate anymore, and the flow pattern is more like a 2D flow. So it is reasonable to use a profile which has lower profile loss, while has larger blade loading to decreases blade number.
Similar Steam Turbine Design
In order to further improve the efficiency of the unit, the HP VHP module uses the single path design. The single path has a longer blade than the double path, and the leakage loss is smaller. The total internal efficiency of steam turbine is expected to exceed 92%.
The LP module uses last stage blades of height 1200mm. The blade has been applied in many 1000MW units, such as Zhou Shan, Wan zhou, Liu heng project.
Dong Fang has designed a new steel last blade whose height is 1400mm. The LP model design has been completed. The exhaust area of the 1400mm blade is 14.5m2 , it’s suitable for low back pressure of 1000MW units or a higher power unit. The 1400mm steel blades will be used in some 1000MW units with low back pressure, such as Yun cheng project.
The 700 ℃ unit needs a lot more research and development. The 630 ℃ unit will become the main trend in the next five years. In particular, after the parameters are improved, the economic performance of the unit can be further improved by combining with double reheating technology. The DongFang 1000MW ultrasupercitical steam turbine has parameters of 35MPa/615℃/630℃/630℃. With double-reheat, the heat rate of the steam turbine is lower than 6800kJ/ kWh, The generating efficiency is expected to exceed 50%. This unit being more efficient than the 620 degree unit, when proved safe and reliable, will become a good option in the future.


Precision flow testing can play an important role in optimizing gas turbine performance. It can determine the performance and expected lifespan of individual components vital to maintaining a reliable and profitable gas turbine.
By combining this information with performance and emissions data, it is possible to suggest improvements to individual components that will benefit overall turbine operation.
Due to the complex nature of individual components and the need for strict tolerances, a small anomaly can develop into a more serious issue that can affect the service life of combustion and hot-gas-path parts. This can result in increased repairs to components, de-rating of the machine, or even taking the gas turbine offline.
Data for each component’s flow test is collected, recorded and reviewed. It is then used to assess the component’s condition and useful life.
Figure 1: Inspection of 501 FD2 dual fuel support housing in Sulzer’s 450 kV, 5-axis digital imaging X-ray booth

Optimizing combustion flows

Vacuum flow testing replicates the direction of flow that occurs on combustion components while in operation. It helps to verify and adjust the flow rate through combustion liners to ensure temperature uniformity (Figure 1).
Fuel enters and mixes with air in the primary mixing zone of the combustion liner. Supplied air is directed through mixing, dilution and the louver features of the liners. The position, size and effective flow area of these features affect the fuel to-air ratio, flame temperature, flame profile, and ultimately the performance and emissions of the turbine.
The effective flow area of combustion liners may change following a repair. This may result from the removal of thermal barrier coatings and base material, for example.
Therefore, the effective flow area needs to be carefully tested after new barrier coatings are reapplied.
Flow testing of first-stage nozzle vane segments should also be considered (Figure 2).
Figure 2: Flow test of 501 DF42 fuel nozzles with steam injection on high-flow test bench 20
The first-stage nozzle consumes a significant portion of air supplied to the compressor discharge case. Turbines that underperform can be affected by the oversupply of cooling air to the first-stage nozzle vane segments. This simultaneously reduces the required air flow for combustion within the liners, limiting the output performance of a turbine. Gas turbines operate in environments where small particles can be ingested and deposited on components. The fouling or blockage of fuel nozzles, for example, can significantly affect turbine performance.
It can also lead to physical damage of the machine. Therefore, blades and buckets should be tested to check that cooling passages are not blocked (Figure 3).
Evaluating uniformity in sets of component flow data can help pinpoint parts that have issues. By comparing data from tests performed when parts are received to those performed after refurbishment, it is possible to identify problems.
Trending this information over time can help develop more informed maintenance schedules and estimates of useful component life.
Liquid flow testing monitors the flow rate of liquid-fuel and water-injection circuits of the fuel nozzles. Liquid flow testing also allows for the visual monitoring of spray patterns, which can indicate component wear or internal blockages. Liquid circuits need to maintain their spray patterns in order to achieve the correct flame profile and temperature distribution. Wear or internal debris may cause combustor burnout. If this occurs, the flame can impinge upon the combustion liner or basket wall and cause component damage.
Figure 3: Flow test of 7001 1st stage bucket on high-flow test bench

Assessing liquid flows

Fuel nozzle flow rates need to match those required by the manufacturer’s design specifications in order to achieve the expected output. These criteria may vary from one turbine to another, even if the turbines are of the same model type. An evaluation of flow data should be performed and made available for inventory spares or sets of fuel nozzles. Large operators minimize downtime during outages by using inventory spares.
Spare fuel nozzles, for example, should be clearly identified with a reference that identifies the turbine they originated from and specific flow data. Large organizations that operate multiple turbines in different locations with an inventory pool of spare parts, may have performance issues after swapping out for an inventory set.
For example, fuel nozzles designed for a turbine at sea level will have different specifications than the same model at another elevation. Without a comparison of flow rates, unknowingly swapping these fuel nozzles can reduce performance and may even affect start-up.
It is wise, then, to carefully review flow data from parts being removed from the turbine as well as those scheduled for installation to ensure there are no major differences.
Even when minimal differences are present, this analysis can determine the need for other actions, including changes to fuel valve settings, operational control adjustments or scheduling the turbine for tuning. Ultimately, flow testing aims to remove anomalies from a system, minimizing variation and delivering a more efficient machine. Minimizing temperature spread and vibration reduces wear to components, lowering repair and maintenance costs.

Automobile Software Can Now be Updated While Driving

With the amount of software in today’s cars in the dimension of millions of lines of code, updating vehicle software today is a cumbersome business. Now Continental has created the necessary technology and infrastructure to enable secure software updates over the air, doing away with the need to visit the garage for every update.
With significance for software for the user experience of car buyers updates having dramatically increased over the past decade or so, automotive manufacturers are feverishly working on solutions to establish similar mechanisms for their vehicles. So far, only Tesla dares to update the software of its cars automatically. All others look jealously over the fence, frightened by the prospect of a terrible glitch or, even worse, a cyber attack against the transmission path. Also, updating a vehicle’s software is somewhat more complex than updating a smartphone’s operating system: Up to 100 computers are involved, and since they are all connected, the activities of most of them can have side effects on others. Plus, the number of possible variants and options in a car is much bigger than in a smartphone. And last but not least, no one can afford a failed software update – in a car such a situation would have far more serious consequences than with a smartphone.
Therefore, despite intensive R&D activities by companies like RedBend Software or Harman, the roll-out of solutions for software updates over the air for cars seemed to got stuck for quite a while. Now it seems like Continental has made the grade: The automotive supplier has developed the necessary solutions at the hardware level in the car and established a reseller relationship with Texas-based company Carnegie Technology which offers a software update platform. Continental will integrate this software into its automotive telematics solutions. The software will run on the next generation of Continental’s telematics module along with a supporting cloud-based component for analysis and diagnosis functions.
During the ride, this technology aggregates the bandwidths of available transmission paths and the seamless handover between mobile radio cells as well as between different wireless technologies such as WiFi, LTE, 3G and satellite connections. As a supplement to the terrestrial networks Continental together with satellite communications provider Inmarsat is currently developing wireless update techniques for satellite-based software updates. This will enable worldwide updates for vehicles and makes car vendors widely independent from mobile radio operators. For the update process, the Continental platform establishes a two-way satellite data connection.
Carnegie’s software solution is constantly monitoring and assessing the quality of the available network connections options. It then selects the connection that promises the fastest, most reliable and most cost-effective connection. Through its VehicleLink function, it can also use smartphones, laptops or similar devices integrated into the car and the bandwidth they can contribute. To reduce communications cost, the system also has access to external WiFi cells. The Carnegie solution also makes sure the downloads are resumed after interruptions, for instance if a car has passed through a tunnel. Likewise, this solution also manages voice calls to and from the vehicle and allows a broad range of priority options.
At the device level, Continental’s in-car networking modules can be either integrated into a smart antenna module or be used as an independent telematics unit. They are complemented by gateway units that in turn are connected to the vehicle’s internal data buses, providing the infrastructure for the OTA updates.
The solutions will be introduced to the public at the international automotive exhibition in September in Frankfurt Germany.

Voith launches variable speed drive for compressors and pumps

New Heat Exchanger Coating Resists Adhesion, Corrosion, Microbes, Nanocoating claims triple benefits

GERMANY: A new nanocoating developed for heat exchangers with anti-adhesive, anti-corrosive and anti-microbial properties could find ready acceptance in the air conditioning industry.


The Saarbrücken-based Leibniz Institute for New Materials is demonstrating the possibilities for the new coating at this year’s Hannover Messe which takes place in April.


 The coating is aimed initially at the food industry where heat exchangers are used extensively by companies such as milk and juice processors. In order to ensure there is no risk to consumers, heat exchangers in these areas have to be free from microbes and must be cleaned at regular intervals using aggressive chemicals. These increase the sensitivity for corrosion, especially if mild steel is used as heat exchanger material.
According to Carsten Becker-Willinger, head of Nanomers at the Leibniz Institute for New Materials, the paint developed could also be used in other contexts, including air conditioning and water purification plants.


The developers achieve the anti-adhesive characteristics in the new coating by introducing hydrophobic compounds that are similar to common Teflon. These inhibit the formation of any undesired biofilm and allow residues to be transported out more easily before they clog up the channels of the heat exchangers. The coating also acts as a diffusion barrier, inhibiting corrosion by corrosive substances or aggressive cleaning agents. Colloidal copper is also used in the coating to prevent microbes, bacteria or fungus from adhering to surfaces.


 “In addition, we can keep the paint chemically stable. Otherwise it would not withstand the aggressive chemicals that are required for cleaning,” explained Carsten Becker-Willinger.


The coating could also be adapted for special mechanical loads where, due to mechanical vibrations, the individual heat exchanger plates could be subjected to a certain amount of abrasion at points of contact.


 The paint can be applied using standard methods such as spraying or immersion and subsequent hardening. It can be used on stainless steel, steel, titanium or aluminium.


The Leibniz Institute for New Materials is a leading center for materials research, conducting research into nanocomposite technology, interface materials, and bio interfaces.

Steam Turbines New steam turbine controller promises easy installation

Voith’s range of digital steam turbine controllers has been extended with the new TurCon DTc. This compact model can be set up quickly and easily to perform all standard control functions on mechanical driven machines and generators. The new controller is “pre-engineered” and suitable for steam turbines of all power classes.
 Fast, simple and cost-effective system integration with the best possible reliability, process quality, productivity and safety are the typical customer specifications for modern steam turbine controllers. Decision-makers of OEMs or engineering contractors and modernizers looking to minimize costs prefer to use controllers that dispense with elaborate installation processes and offer a high degree of flexibility. Operators of steam turbines expect a reliable product that uses proven control algorithms to ensure high process quality and productivity.Because the controller is “pre-engineered” the customer only has to set the selected parameters, which keeps installation work to a minimum. There is no need to buy additional special software; data can be displayed at any time via the control panel or via the connected control system.
 The TurCon DTc consists of two rugged assemblies, an intuitive 7″ TFT-LCD touchscreen control panel with integrated CPU and a remote I/O unit. The controller can be integrated into existing Industry 4.0 environments via a standardized Ethernet interface with Modbus TCP or OPC. An optional control panel or PC can be connected via the LAN interface, for example as part of a commissioning process or remote monitoring scenario.
 The option of simultaneously controlling a maximum of 4 HP and 2 LP control valves is another special feature of the TurCon DTc. This means that there is no need to adjust the valves mechanically using a camshaft or via a separate valve coordinator (split range).
Other key elements ensuring reliability and availability include the three frequency inputs with a 2-out-of-3 voting for the speed sensors. The fault-tolerant speed measuring equipment offers high reliability and availability. An integrated simulation mode allows commissioning personnel to check whether the parameter settings are actually correct and improve them if necessary prior to hot commissioning. This minimizes the risk of damage due to incorrect parameters.
 The TurCon DTc archives the last 1,000 status, warning and alarm messages with a time stamp, allowing process flows and malfunctions to be easily identified and traced. As a result, fast, targeted optimizations are possible.
 Voith Digital Solutions bundles Voith’s long standing automation and IT expertise with the know-how in the fields of water power, paper machines and drive engineering.

Gas Turbines: How ambient temperature affects gas turbine types

Changes in ambient temperature have an impact on fullload power and heat rate of a gas turbine, but also on part-load performance and optimum power turbine speed. Manufacturers typically provide performance maps that describe these relationships for ISO conditions.
The excerpts are taken from a paper “Gas turbine performance” presented by Rainer Kurz of Solar Turbines and Klaus Brun of Southwest Research Institute at the 2015 Middle East Turbomachinery Symposium.
The performance curves are the result of the interaction between the various rotating components and the control system. This is particularly true for DLN engines. If the ambient temperature changes, the engine is subject to the following effects:
The air density changes. Increased ambient temperature lowers the density of the inlet air, thus reducing the mass flow through the turbine, and therefore reduces the power output (which is proportional to the mass flow) even further. At constant speed, where the volume flow remains approximately constant, the mass flow will increase with decreasing temperature and will decrease with increasing temperature.
The pressure ratio of the compressor at constant speed gets smaller with increasing temperature. This can be determined from a Mollier diagram, showing that the higher the inlet temperature is, the more work (or head)is required to achieve a certain pressure rise. The increased work has to be provided by the gas generator turbine, and is thus lost for the power turbine, as can be seen in the enthalpy-entropy diagram. At the same time NGgcorr (ie the machine Mach number) at constant speed is reduced at higher ambient temperature. As explained previously, the inlet Mach number of the engine compressor will increase for a given speed, if the ambient temperature is reduced. The gas generator Mach number will increase for reduced firing temperature at constant gas generator speed.
The Enthalpy-Entropy Diagram describes the Brayton cycle for a two-shaft gas turbine. Because the head produced by the compressor is proportional to the speed squared, it will not change if the speed remains the same. However, the pressure ratio produced, and thus the discharge pressure, will be lower than before. Looking at the combustion process, with a higher compressor discharge temperature and considering that the firing temperature is limited, we see that less heat input is possible, ie., less fuel will be consumed .The expansion process has less pressure ratio available or a larger part of the available expansion work is being used up in the gas generator turbine, leaving less work available for the power turbine.
On two-shaft engines, a reduction in gas generator speed occurs at high ambient temperatures. This is due to the fact that the equilibrium condition between the power requirement of the compressor (which increases at high ambient temperatures if the pressure ratio must be maintained) and the power production by the gas generator turbine (which is not directly influenced by the ambient temperature as long as compressor discharge pressure and firing temperature remain) will be satisfied at a lower speed. The lower speed often leads to a reduction of turbine efficiency: The inlet volumetric flow into the gas generator turbine is determined by the first stage turbine nozzle, and the Q3/NGG ratio (i.e., the operating point of the gas generator turbine) therefore moves away from the optimum.
Variable compressor guide vanes allow keeping the gas generator speed constant at higher ambient temperatures, thus avoiding efficiency penalties. In a single-shaft, constant speed gas turbine one would see a constant head (because the head stays roughly constant for a constant compressor speed), and thus a reduced pressure ratio. Because the flow capacity of the turbine section determines the pressure-flow-firing temperature relationship, equilibrium will be found at a lower flow, and a lower pressure ratio, thus a reduced power output.
The compressor discharge temperature at constant speed increases with increasing temperature. Thus, the amount of heat that can be added to the gas at a given maximum firing temperature is reduced.
The relevant Reynolds number changes: At full load, single-shaft engines will run a temperature topping at all ambient temperatures, while two-shaft engines will run either at temperature topping (at ambient temperatures higher than the match temperature) or at speed topping (at ambient temperatures lower than the match temperature). At speed topping, the engine will not reach its full firing temperature, while at temperature topping, the engine will not reach its maximum speed. The net effect of higher ambient temperatures is an increase in heat rate and a reduction in power. The impact of ambient temperature is usually less pronounced for the heat rate than for the power output, because changes in the ambient temperature impact less the component efficiencies than the overall cycle output.
By TMI Staff & Contributors
IESG Engineering have a service generating performance models of equipment (gas turbines, generators, boilers, HRSGs, SCRs and other equipment) based on different percentage loads and seasons, minimizing downtime and maximizing performance.

Energy Sources

Over the last 200 years an ever-increasing proportion of our energy has come from non-renewable sources such as oil and coal. While demand for energy rises these resources are running out and scientists are exploring the potential of renewable sources of energy for the future.
Renewable and non-renewable energy resources All life on earth is sustained by energy from the sun. Plants and animals can store energy and some of this energy remains with them when they die. It is the remains of these ancient animals and plants that make up fossil fuels. Fossil fuels are non-renewable because they will run out one day. Burning fossil fuels generates greenhouse gases and relying on them for energy generation is unsustainable. Hence the need to find more renewable, sustainable ways of generating energy. Renewable or infinite energy resources are sources of power that quickly replenish themselves and can be used again and again. Some resources can be thought of as both renewable and non-renewable.
  • Wood can be used for fuel and is renewable if trees are replanted.
  • Biomass, which is material from living things, can be renewable if plants are replanted.
Non-renewable energy resources


Watch below table in a Wide Screen mode for a mobile option.
Type of fuel


               Where it is from

Coal (fossil fuel)
  • Formed from fossilised plants and consisting of carbon with various organic and some inorganic compounds.
  • Mined from seams of coal, found sandwiched between layers of rock in the earth.
  • Burnt to provide heat or electricity.
  • Ready-made fuel.
  • It is relatively cheap to mine and to convert into energy.
  • Coal supplies will last longer than oil or gas.
  • When burned coal gives off atmospheric pollutants, including greenhouse gases.
Oil (fossil fuel)
  • A carbon-based liquid formed from fossilized animals.
  • Lakes of oil are sandwiched between seams of rock in the earth.
  • Pipes are sunk down to the reservoirs to pump the oil out.
  • Widely used in industry and transport.
  • Oil is a ready-made fuel.
  • Relatively cheap to extract and to convert into energy.
  • When burned, it gives off atmospheric pollutants, including greenhouse gases.
  • Only a limited supply.
Natural gas (fossil fuel)
  • Methane and some other gases trapped between seams of rock under the earth's surface.
  • Pipes are sunk into the ground to release the gas.
  • Often used in houses for heating and cooking.
  • Gas is a ready-made fuel.
  • It is a relatively cheap form of energy.
  • It's a slightly cleaner fuel than coal and oil.
  • When burned, it gives off atmospheric pollutants, including greenhouse gases.
  • Only limited supply of gas.
  • Radioactive minerals such as uranium are mined.
  • Electricity is generated from the energy that is released when the atoms of these minerals are split (by nuclear fission) in nuclear reactors.
  • A small amount of radioactive material produces a lot of energy.
  • Raw materials are relatively cheap and can last quite a long time.
  • It doesn't give off atmospheric pollutants.
  • Nuclear reactors are expensive to run.
  • Nuclear waste is highly toxic, and needs to be safely stored for hundreds or thousands of years (storage is extremely expensive).
  • Leakage of nuclear materials can have a devastating impact on people and the environment. The worst nuclear reactor accident was at Chernobyl, Ukraine in 1986.
  • Biomass energy is generated from decaying plant or animal waste.
  • It can also be an organic material which is burned to provide energy, eg heat, or electricity.
  • An example of biomass energy is oilseed rape (yellow flowers you see in the UK in summer), which produces oil.
  • After treatment with chemicals it can be used as a fuel in diesel engines.
  • It is a cheap and readily available source of energy.
  • If the crops are replaced, biomass can be a long-term, sustainable energy source.
  • When burned, it gives off atmospheric pollutants, including greenhouse gases. If crops are not replanted, biomass is a non-renewable resource.
  • Obtained from felling trees, burned to generate heat and light.
  • A cheap and readily available source of energy.
  • If the trees are replaced, wood burning can be a long-term, sustainable energy source.

  • When burned it gives off atmospheric pollutants, including greenhouse gases.
  • If trees are not replanted wood is a non-renewable resource.
How long will fossil fuels last? Estimates from international organizations suggest that if the world’s demand for
energy from fossil fuels continues at the present rate that oil and gas reserves may run out within some of our lifetimes. Coal is expected to last longer. Estimated length of time left for fossil fuels
Fossil fuel
Time left
50 years
Natural gas
70 years
250 years


Next-Generation Wind Technology

Innovation in the design and manufacturing of wind power generation components continues to be critical to achieving our national renewable energy goals. As a result of this challenge, the U.S. Department of Energy’s Wind Program and Advanced Manufacturing Office are partnering with public and private organizations to apply additive manufacturing, commonly known as 3D printing, to the production of wind turbine blade molds.
The Wind Program works with industry partners to increase the performance and reliability of next-generation wind technologies while lowering the cost of wind energy. The program’s research efforts have helped to increase the average capacity factor (a measure of power plant productivity) from 22% for wind turbines installed before 1998 to an average of 33% today, up from 30% in 2000. Wind energy costs have been reduced from over 55 cents (current dollars) per kilowatt-hour (kWh) in 1980 to an average of 2.35 cents in the United States today.
To ensure future industry growth, the technology must continue to evolve, building on earlier successes to further improve reliability, increase capacity factors, and reduce costs. This page describes the goal of the program’s large wind technology research efforts and highlights some of its recent projects.
The newest inventions coming out of the DOE Wind Program can also be found on the Energy Innovation Portal, which houses all technologies available for licensing funded by the DOE’s Office of Energy Efficiency and Renewable Energy.
Research Project Highlights
These are some of the key research project highlights from the program’s next-generation wind technology research. From 2006 to 2014, the Wind Program provided awards totaling more than $160 million for projects focused on testing, manufacturing, and component development.
Prototype Development
Modern wind turbines are increasingly cost-effective and more reliable, and have scaled up in size to multi-megawatt power ratings. Since 1999, the average turbine generating capacity has increased, with turbines installed in 2014 averaging 1.9 MW of capacity. Wind Program research has helped facilitate this transition, through the development of longer, lighter rotor blades, taller towers, more reliable drivetrains, and performance-optimizing control systems. Furthermore, improved turbine performance has led to a more robust domestic wind industry that saw wind turbine technology exports grow from $16 million in 2007 to $488 million in 2014.
During the past two decades, the program has worked with industry to develop a number of prototype technologies, many of which have become commercially viable products. One example is the GE Wind Energy 1.5-megawatt (MW) wind turbine. Since the early 1990s, the program worked with GE and its predecessors to test components such as blades, generators, and control systems on generations of turbine designs that led to GE’s 1.5-MW model. The GE 1.5 constitutes approximately half of the nation’s installed commercial wind energy fleet, and is a major competitor in global markets.
Component Development
The program works with industry partners to improve the performance and reliability of system components. Knight and Carver’s Wind Blade Division in National City, California, worked with researchers at the Department of Energy’s Sandia National Laboratories to develop an innovative wind turbine blade that has led to an increase in energy capture by 12% The most distinctive characteristic of the Sweep Twist Adaptive Rotor (STAR) blade is a gently curved tip, which, unlike the vast majority of blades in use, is specially designed to take maximum advantage of all wind speeds, including slower speeds.
To support the development of more reliable gearboxes, the program has worked with several companies to design and test innovative drivetrain concepts. Through the support of $47 million in DOE funding, the nation’s largest and one of the world’s most advanced wind energy testing facilities was opened at Clemson University to help speed the deployment of next generation energy technology, reduce costs for manufacturers and boost global competitiveness for American companies. The Clemson facility is equipped with two testing bays – for up to 7.5-megawatt and 15-megawatt drivetrains, respectively. The Clemson facility also features a grid simulator that mimics real-world conditions, helping researchers better study the interactions between wind energy technologies and the U.S. power grid.
Utility-Scale Research Turbine
In 2009, the program installed a GE 1.5-MW wind turbine at the National Wind Technology Center (NWTC) located on the National Renewable Energy Laboratory campus in Boulder, Colorado. This turbine was the first large-scale wind turbine fully owned by DOE and serves as a platform for research projects aimed at improving the performance of wind technology and lowering the costs of wind energy. The NWTC is now collaborating with Siemens Energy to conduct aerodynamic field experiments on a 2.3-MW wind turbine. These experiments utilize sonic as well as conventional anemometers and wind vanes on the NWTC’s 135 meter meteorological tower to measure characteristics such as inflow, turbine response, and wind wake. The data gained from these experiments will provide new insights into multi-megawatt turbine aerodynamic response, structural loading, power production, and fatigue life that can be used to increase reliability and performance. The research being done at the NWTC complements DOE’s Atmosphere to Electrons (A2e) initiative that targets significant reductions in the cost of wind energy through an improved understanding of the complex physics governing wind flow into and through wind farms.



HRSG steam pipe leaks downstream of the attemperators.

When we are talking about any kind of vehicle or a combined cycle plant, the crucial point to successful operation of any power equipment is an effective maintenance plan. This aids maintenance managers strategize ahead, minimize unforeseen failures, and accommodate limitations forced by financial and outage resources. Cost, outage time and contractor manpower are some of the factors to be considered.
Each plant may select a different maintenance plan. Some may want to max up the synchronization of Heat Recovery Steam Turbine (HRSG) maintenance with the overhaul of the gas turbine (GT) or steam turbine (ST) to exploit outage time. Others may struggle to level their costs by fluctuating as much HRSG maintenance to the years before or after the GT and ST outage window to avoid large peaks in annual maintenance costs.
This is important when you take into consideration the fact that hundreds of F-class or larger HRSGs were commissioned in the 2000-to-2005 time period. Therefore many are about half-way through their original specified design life.
Figure 1: Replacement of attemperator piping must be planned well in advance

Figure 1: Replacement of attemperator piping must be planned well in advance

Component redesigns
Factor in the severe increase in plants conducting HRSG cycling, and many of these HRSGs can presume to need major component redesigns and replacements in the next ten years. Consequently combined cycle power plants will need more attention and coordination over the next few years than they did in the earlier ten to identify and plan for the possibility of HRSG capital projects.
There are many large HRSG projects that managers of combined cycle plants should evaluate thoroughly and include in any predictions being done as part of GT and ST maintenance planning. Attemperator piping failure and replacement is a vital area to take into account (Figure 1).
Problems in this part of the HRSG are frequently caused by a desuperheater overspray and short distance from a feedwater inlet to downstream elbow where liquid water is not able to completely vaporize before it comes into contact with a pipe and extinguishes it.
Desuperheater overspray is an operational problem and can happen when steam is sprayed to saturation or within 50°F of saturation temperature. But even well designed and correctly operated desuperheater arrangements can experience a pipe failure.
All it takes is one leaky feedwater valve or faulty desuperheater probe. Some gas turbine upgrades from OEMs that allow lower loads and changes to the turbine exhaust conditions can aggravate this problem. Issues with attemperator piping are no small matter as redesigned piping systems can take 40 or more weeks to design and supply. Their assessment involves visual inspection of superheaters and reheaters for bowing, check of performance data to look for indicators of overspray, and quality non-destructive evaluation (NDE) of piping locations at risk to stress and cracking.
Another common area of combined cycle maintenance is duct burner replacement. This occurs due to burner failure from cracking initiated at the nozzles or from overheated, warped and burnt away components. Detection requires visual inspection, both off-line and on-line, and review of maintenance history of comparable designs (Pictures 3 & 4 in the slideshow).
Poor burner flame patterns or burner element failures may force a derate of a steam turbine generator from its maximum full-load, full-duct firing power output. A burner derate on one HRSG can affect not only that HRSG, it can also derate adjacent HRSGs if they are part of a 2×1, 3×1 or 4×1 steam turbine configuration within a combined cycle plant.
Figure 2: A badly bowed duct burner inside HRSG

Figure 2: A badly bowed duct burner inside HRSG

With full-duct firing at full load, it becomes important to have relatively balanced steam flows across each HRSG to elude tube overheat issues. The challenging side of a thorough duct burner inspection, however, is inspecting elements at higher elevations.
It would consequently be wise for maintenance managers to plan on building a scaffold, mobilizing a Sky Climber or even a drone examination as a part of a regular maintenance. This is especially significant if a history of duct burner complications already exists.