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Wind power technology breakthroughs will enable it to play pivotal role in the world’s future Renewable energy supply

Renewable energy is at the centre of the transition to a less carbon-intensive and more sustainable energy system. Renewables have grown rapidly in recent years, accompanied by sharp cost reductions for solar photovoltaics and wind power in particular. The future development of wind power presents a significant opportunity in terms of providing low carbon energy. Wind power could prevent more than 1 billion tonnes of carbon dioxide from being emitted each year by dirty energy – equivalent to the emissions of Germany and Italy combined,Sven Teske, Greenpeace senior energy expert, had said. Large Growth of Wind energy is predicted as  countries develop more renewable energy to meet emissions cut targets and prices continue to fall.

 

Wind energy will achieve record growth globally over the next five years, the Global Wind Energy Council (GWEC) trade association said in Nov 2020, as the impact of COVID-19 has only been to delay, not cancel, projects. “While some project completion dates have been pushed into 2021 due to the pandemic, next year is expected to be a record year for the wind industry with 78 GW (gigawatts) of new wind capacity forecast to be installed in 2021,” GWEC said in an outlook report. In total some 348 GW of new onshore and offshore capacity are expected by the end of 2024, which would take cumulative wind power capacity to almost 1,000 GW, GWEC said. “Over 50% of the onshore wind capacity added between 2020 to 2024 will be installed in China and the U.S., led by installation rushes to meet subsidy deadlines,” it added.

 

While much of the current installations are coming from mature markets such as Europe, where there were 18 GW installed capacity by the end of 2018, most of the new growth will come from emerging markets. Asia is set to become a leader in offshore wind, with 100 GW of offshore capacity to be installed until 2030. China will make up most of this capacity, even taking over the leading position from Europe, while other Asian markets such as Taiwan, Japan, South Korea and India will also become increasingly important in the coming years. China is the world’s largest wind power market in both new and cumulative installations. In 2018, the country installed 20.2 GW of onshore wind energy and 1.6 GW of offshore wind farm, representing 44% and 37% of global market share respectively.

 

The demand of wind power is predicted for big growth in the future, Wind power will account for 14% of the world’s primary energy supply — one percentage point above solar PV — by mid-century.  Wind will also provide 36% of world electricity generation by 2050, with two-thirds of this generation coming from onshore projects, according to the company’s Energy Transition Outlook report, which was released in sep 2017.

Challenges  of   Wind power

It also presents several challenges. It needs to be cost competitive compared with the use of fossil fuels and other competitor renewable energy sources, most notably solar photovoltaics. Wind is a emerging as a reliable and inexpensive source of renewable energy. The costs of wind energy have fallen rapidly over the last few years and are expected to continue to decrease. Globally, the average cost of wind is $83 per megawatt-hour compared to averages for coal and gas being $84 and $98 respectively.

 

“In the USA, gas is slightly cheaper than wind but this is the only large economy where that is the case. As a comparison, solar photovoltaic energy averages $122 globally for each MW-hour,” said Giles Dickson who is CEO of the European Wind Energy Association (EWEA). Wind energy pricing remains attractive, according to an annual report released by the U.S. Department of Energy and prepared by Lawrence Berkeley National Laboratory (Berkeley Lab). At an average of around 2 cents per kilowatt-hour (kWh), prices offered by newly built wind projects in the United States are being driven lower by technology advancements and cost reductions. Wind power’s costs will tumble by 16% as capacity doubles over the next 33 years, while the cost of solar PV is set to fall by 18% over this timescale.

 

The challenges of wind power are the intermittency and variability of the wind resource, and hence of wind turbine output. The intermittency and variability of the wind resource, and hence of wind turbine output, pose challenges to the integration of wind power generation to the existing electricity network. Intermittent generation will be evident at site level, but due to geographical diversity will reduce when generation is considered over larger areas (such as country or regional level). Hence, the intermittency of wind generation can be reduced significantly if the power outputs of wind farms over a specific area are aggregated together.

 

In Feb 2021 , Texas the energy powerhouse of the US,  while facing historic freezing conditions froze the state’s power facilities and mainly its 10,700 wind turbines. Nearly half of Texas’ installed wind power generation capacity has been offline because of frozen wind turbines in West Texas, according to Texas grid operators. Fortunately for the Electric Reliability Council of Texas, which manages the state’s electric grid, the storm’s gusty winds are spinning the state’s unfrozen coastal turbines at a higher rate than expected, helping to offset some of the power generation losses because of the icy conditions. Texas uses a range of power sources, including coal, gas and nuclear facilities, all of which are down amid the deep freeze that blanketed the state.

 

Onshore (on land) or offshore (sea or freshwater) Wind Farms

Wind farms can be based onshore (on land) or offshore (sea or freshwater).  Onshore wind farms are considerably less expensive than offshore wind turbines, they are cheapest form of renewable energy as compared to offshore wind farms, solar and nuclear power sources, however they cannot produce energy all year round due to the poor wind speed and/or physical blockage of the wind by buildings and/or hills. Turbines are optimized at a specific speed, which can limit their efficiency as a result of the unpredictable speed and direction of winds at these locations.

 

The steady speed and pressure of the winds at offshore locations are more reliable and efficient compared to onshore winds, therefore it is clearly beneficial for future developments in wind technology to look towards improving offshore turbines.  Although offshore turbines are more prone wear and tear due to their location, current advancements in the technology of offshore turbines strengthen the tower to handle the loading forces of waves or ice flows.

 

University of Delaware researchers report in a new study that offshore wind may be more powerful, yet more turbulent than expected in the North Eastern United States. Explaining how wind can be stable, unstable or neutral is a tricky business, Archer says.” When the atmosphere is stable, winds are smooth and consistent (think of when a pilot tells airline passengers to sit back and enjoy. When the atmosphere is unstable, it is similar to turbulence experienced by airline passengers during a flight—the wind is choppy and causes high winds from above and slow winds from below to crash into each other and mix together, causing a bumpy and unpredictable ride for the air current.” Neutral conditions hover in the middle, with an average amount of turbulence and wind speed variation.

 

The findings, published in a paper in the Journal of Geophysical Research: Atmospheres, could have important implications for the future development of offshore wind farms in the U.S., including the assessment of how much wind power can be produced, what type of turbines should be used, how many turbines should be installed and the spacing between each.

 

An expert in designing offshore wind farms, Archer says the findings may have implication on how future offshore wind farms in the region are designed. “The advantage of these turbulent conditions is that, at the level of the turbines, these bumps bring high wind down from the upper atmosphere where it is typically windier. This means extra wind power, but that extra power comes at a cost: the cost of more stress on the turbine’s blades,” explains Archer. “If you have increased turbulence, you’re going to design a different farm, especially with regard to turbine selection and spacing. And guess what? Even the wind turbine manufacturing standards are based on the assumption of neutral stability,” Archer says.

 

The reliability of a wind turbine in generating power is indicated by the availability of the turbine, which is the proportion of time the turbine is ready for operation. Onshore turbines typically have availabilities of 98%, while offshore turbine availabilities are slightly lower (95-98%) but are improving due to better operation and maintenance

 

Tech innovations

There are two ways to produce more power from the wind in a given area. The first is with bigger rotors and blades to cover a wider area. That increases the capacity of the turbine, i.e., its total potential production. The second is to get the blades up higher into the atmosphere, where the wind blows more steadily. That increases the turbine’s “capacity factor,” i.e., the amount of power it actually produces relative to its total potential (or more colloquially: how often it runs). So the third engineering challenge is to find designs and materials that can stand up to the stresses that come along with height and higher winds. Engineers are coming with many innovative solutions to meet these challenges.

 

A study was conducted by researchers from Berkeley Lab, the National Renewable Energy Laboratory (NREL), University of Massachusetts,  found that wind power cost could be reduced by 24 to 30 percent by 2030 based on the advances in turbine technology that are either projected or already being seen today. Those experts said that by 2030, both onshore and offshore wind turbines will get bigger, leading to additional cost reductions and smoother energy generation.

 

In 2015, a paper from the Department of Energy (DOE) suggested that increasing rotor diameter and height is the best way to access more power from wind turbines, even in areas with lower wind speeds. A wind turbine’s blades convert kinetic energy from the movement of air into rotational energy; a generator then converts this rotational energy to electricity. The wind power that is available is proportional to the dimensions of the rotor and to the cubing of the wind speed. Theoretically, when the wind speed is doubled, the wind power increases by a factor of eight.

 

In 2015, onshore wind turbines averaged a hub height of 82m, a rotor diameter of 102m, and a power output of 2 MW. In 2030, experts on average suggest that onshore wind turbines will have a hub height of 115m, a rotor diameter of 135m, and a power output of 3.25 MW. Offshore, the story is more dramatic. Where today’s turbines have a hub height of 90m, a rotor diameter of 119m, and a power output of 4.1 MW on average, 2030’s offshore wind turbines will measure 125m and 190m in hub height and rotor diameter, respectively, and output an insane 11 MW on average—each.

 

The levelised cost of energy from offshore wind farms in Europe could be reduced by as much as a third by 2030 if a range of technological innovations such as larger turbines and more efficient rotors are deployed.That is the conclusion of a new report released last week by sustainable energy technology investor KIC InnoEnergy and technical consultancy BVG Associates. The study used KIC InnoEnergy’s offshore wind cost model to analyse the extent to which 51 innovations could help cut the cost of wind energy through changes to design, hardware, software or processes.

 

The changes included the introduction of mass-produced support structures for use in deeper water with larger turbines, using bespoke vessels and equipment capable of operating in a wider range of conditions, and the use of more upfront investment in wind farm development to improve site investigations and engineering studies.

 

Two-thirds of the estimated cost savings were found to be achievable through just nine areas of innovation, such as improvements in blade aerodynamics and optimising the layout of arrays. The innovation with the largest potential impact on cost reduction was increasing turbine size from 4MW to 10MW, the analysis found, since using fewer turbines leads to significant savings in the cost of foundations, construction, and operations.

 

Turbines have aerodynamic ‘smart’ blades made of carbon composite with wireless sensors, and can ‘pitch’ in and out of the wind in response to shifts in air flow. “There has been a huge leap forward in technology even over the last couple of years. They are pushing the boundaries of energy capture,” said Cian Cornroy from the offshore experts ORE Catapult in Glasgow. “They are using new metals in the generators that cut the need for servicing. There are cameras to relay digital data through cloud computing that can reset the turbines. You have to be bullish,” he said.

 

Direct Drive and Gearbox Wind Turbines

Two types of wind turbines share the focus of current development efforts, and are competing to be recognized as the dominant design: the gearbox, and the direct-drive wind turbines.There has been a shift in wind turbine technology in the last few decades, which has lead to the variable speed wind turbine with a multi-stage gearbox. This type of turbine has a gearbox between the low-speed rotor and a higher speed electrical generator (usually a relatively standard doubly-fed induction generator). The purpose of the gearbox is to increase the rotational rotor speed before feeding it to the generator.

Image result for Direct Drive and Gearbox Wind Turbines

This type of wind turbine presents a challenge for designers because of the loading and environmental conditions required for the gearbox operation. The power is generated via torque from the rotor; however, large moments and forces are also applied by the turbine rotor on the wind-turbine drivetrain. To prevent stress concentration and failures, designers must adjust the gearbox to support the loads and stress. Seals and lubrication systems must operate consistently in wide temperature variations; otherwise, dirt and moisture may collect and build-up inside the gearbox.

 

For this wind turbine type, the blades rotate by a shaft connected via a gearbox to the generator. For example, to generate electricity in the case of a 1 MW wind turbine, the gearbox increases the rotation speed of the blades from 15 to 20 rotations per minute up to the about 1,800 rotations per minute that is required.

 

To eliminate gearbox failure and transmission losses, manufacturers have developed wind turbines without gearboxes. This type of wind turbine was introduced in 1991, and is known as the variable speed direct-drive wind turbine. Direct-drive technology is the basis for direct-drive wind turbines; as Shown in the image below, the synchronous generator is directly powered by the rotor.

 

A direct-drive wind turbine’s generator speed is equivalent to the rotor speed, because the rotor is connected directly to the generator. As the rotational generator speed is low, designers placed several magnetic poles in the generator to achieve the appropriate high output frequency. The there are two categories of wind turbine generators: permanent magnet generators (PMGs) and electrically excited synchronous generators (EESGs).

 

EESGs do not have permanent magnets made from rare materials, such as neodymium, the extraction of which can cause environmental damage. On the other hand, PMGs have several advantages such as high efficiency with the elimination of field loss, in addition to being small and lightweight compared to the EESGs. PMGs are usually used in small-scale wind turbines, but can also be used in large MW applications.

 

However, because the high torque requirements are large, direct-drive wind turbines up to 7-10 MW require significantly larger and heavier generators. In this case, a single or two-stage gearbox is the better choice, as it is a much smaller, lighter solution and it provides the same advantages as the direct-drive generator.

 

An advantage of direct-drive turbines is the high efficiency of synchronous permanent magnet generators. An important fact is that due to wind inconsistency, the turbines often operate at partial loads. The efficiency of the PM generator excels even in these conditions because it continues working nearly to nominal values.

 

The developments in direct-drive magnets and generator arrangements resulted in a more affordable, lighter direct-drive model. The price of the permanent magnets used in direct drive turbines has also dropped significantly, increasing the popularity of the direct-drive turbines. Direct-drive eliminates the gearbox, and could be crucial in removing the limiting size and weight of future turbines of 10 MW and beyond.  Hybrid drive systems have simpler and more reliable gearing than conventional solutions with three stages of gearing, while having a similar generator size.

 

The most important factors for selecting proper wind turbines are cost and technology reliability. The cost of energy is the key factor that influences the strategic decision for building new wind farms. Ideally the price should remain fixed for a prescribed period, which would allow for insight into the technology that provides the lowest cost of energy being at an advantage over its competitors.

 

The second important factor is the reliability of wind turbines. Wind turbines are required to operate in various locations, from easily accessible fields to remote offshore or mountain locations. Repairs and unscheduled maintenance resulting from poor reliability can be extremely costly and time-consuming. Technologies such as smart online monitoring can increase overall reliability.

 

Modern turbines with blades that stretch 450 feet (137 meters) in the air already can twist and turn and spin faster or slower to adjust to ever-changing breezes. And they’re covered with sensors and control systems to make adjustments quickly. Remote electronic controls are continually being incorporated into turbine design. In addition to pitch control and variable speed operation, individual turbines and whole farms may perform wind measurements remotely, using turbine-mounted technology such as lidar (LIght Detection and Ranging) and sodar (SOnic Detection and Ranging). The real-time data realised from remote sensing will optimise wind production as turbines constantly pitch themselves to the incoming wind.

 

But many still aren’t able to fully exploit weather and operational data in real time. For example, on wind farms with hundreds of turbines, the front wall of propellers creates a wake that reduces the efficiency for those behind. Making each unit more integrated with the rest could boost output as much as 15 percent, according WindWISDEM, an wind-industry software startup funded by venture capital firm YStrategies Corp.

 

Innovations will be needed for the next stage of growth in wind power. Utilities are demanding that sources of renewable energy deliver more dependable flows to transmission grids. So, the industry is trying to use data analysis to narrow the efficiency gap in existing systems and better predict how much power they can supply to consumers before it’s actually needed. “The grid likes certainly,” said Julia Attwood, an analyst at Bloomberg New Energy Finance. “If renewables can be more sure about their production, then that means they can supply more power because the grid operator can work that into their schedule for the day.

 

High-Efficiency, Lightweight Wind Turbine Generators

WETO supported three projects to funded three projects develop next-generation wind turbine drivetrain technologies that will facilitate the continued growth of wind turbines. Lightweight generators are important because the size and weight of the generator impact the weight and cost of the wind turbine tower and foundation, as well as the specialized equipment needed to transport and install the large components. General Electric (GE) Research designed a prototype high-efficiency ultra-light low temperature superconducting generator that leverages investments from the magnetic resonance imaging (MRI) industry, eliminates the need for foreign-sourced rare earth materials, and reduces generator mass as compared to current technologies. WEG Energy Corporation developed a high-efficiency permanent magnet direct drive lightweight generator to integrate into its existing platform. American Superconductor Corporation developed a high-efficiency lightweight wind turbine generator that incorporates high-temperature superconducting materials to replace permanent magnets in the generator rotor.

 

Smart rotors

Larger rotor blades make it necessary to consider blade/rotor concepts that can adjust themselves to non-homogeneous wind flow like gusts, turbulence spots, shear, etc. For very long blades, i.e. greater than 70 m, it is very hard to define the optimal operational point, since the inflow situations may vary quite a lot along the blade. Therefore, a local optimal blade setting, i.e. adjusted to the flow on a scale of metres or tens of metres, makes sense. This could reduce loads, increase or smooth out power output or help in wind turbine or wind farm control. Devices which integrate this type of concept fall into the category of smart rotor technology. This concept could incorporate both active and/or passive load alleviation systems.

 

Multi-rotor wind turbines

To improve efficiency and reduce overall loads on a wind turbine it is possible to replace a large single rotor with a multiple-rotor system (MRS). This innovative solution could allow a large power system (20 MW or more) to be installed at a single site by means of a high number of standardised rotors. As mentioned above, scaling up is seen as a key factor in overall cost reduction.

 

Fig. 8

Bat Deterrent System Commercialized

A WETO-supported bat deterrent system developed by NRG Systems, Inc. of Vermont has been successfully commercialized. NRG announced in July 2020 that Siemens Gamesa Renewable Energy (SGRE) was providing installation support of the bat deterrent system, which uses nacelle-mounted ultrasound-generating devices and a controller integrated with the turbine’s SCADA system to deter bats from wind turbines. SGRE has installed the system on its wind turbines in Ontario, Canada, and Maui, Hawaii.

 

3D Thermal Tracking of Birds and Bats

Commissioned by WETO, DOE’s Pacific Northwest National Laboratory developed ThermalTracker-3D, a stereo-vision solution for evaluating flight tracks and other data on birds and bats around offshore wind turbines. The technology uses thermal video that records movement day or night, even in limited visibility conditions. ThermalTracker-3D continuously transmits satellite data showing if and when birds and bats are active near proposed wind farms, without the need for researchers to travel to the deployment site.

De-icing technology

In case of Texas Energy crisis in Feb 2021,  it seems that the choice of energy is not to blame for power outages, it is how the wind turbines were designed. Texas’ turbines were built more than eight years ago when de-icing technology was not widely available and due to its warmer climate, many officials may not have even considered such additions.

 

But according to the Swedish firm, carbon fiber and heat sensors could have avoided the current power outage crisis. Stefan Skarp, head of wind power at Skelleftea Kraft, told Bloomberg: ‘The problem with sub-zero temperatures and humid air is that ice will form on the wind turbines.’ ‘When ice freezes on to the wings, the aerodynamic changes for the worse so that wings catch less and less wind until they don’t catch any wind at all.’ Skarp notes that although the de-icing technologies are the way to go when using wind turbines, they are also more costly. Such winter-proof units are about five percent more expensive and output from the turbines may also be reduced in order for the system to keep warm, Sharp explained to Bloomberg.

 

Canada is home to wind farms, but experiences deep freezes about 20 percent of the time between November and April. Officials have opted for ‘cold weather packages’ that heat crucial turbine components such as the gearbox, yaw and pitch motors, according to the Canadian government. The special technologies have allowed some turbines to operate in temperatures as low as -22F (-30C).

Diffuser augmented wind turbines or Wind Lens

The Wind Lens is the brainstorm of researchers at Kyushu University that would generate more than traditional wind power using a unique design. The Wind Lens focuses airflow just like a lens focusing light. The circle made up of the turbine blades has a ring that curves inward, and this directs the flow of air, and accelerates the speed. The team leader states that by using an inlet shroud, diffuser and brim in the inward ring, these cause the air to be drawn in more quickly. This means that it generates more power. The researchers have claimed that using this new wind turbine technology will allow turbines to triple their output, while even reducing the noise that the turbines cause.

 

Diffuser Augmented Wind Turbines (DAWTs), also known as wind lens or shrouded wind turbines, are HAWTs which possess a diffuser-type structure resembling a funnel, able to collect and concentrate the approaching wind. The diffuser can be modified by adding a broad ring or brim around the exit point and an inlet shroud at the entrance, thus creating a ‘lens effect’. This design increases diffuser performance and it has been demonstrated as producing increased power compared to conventional turbines, for a given turbine diameter and wind speed

 

Wind Lens holds great promise for Japan as a source of green renewable energy. Since Japan is an island, it will be able to make full use of offshore wind farms, since that is where researchers feel the new technology will perform the best. The Wind Lens can float on platforms shaped like hexagons, and at sea will not be subject to large waves or tsunamis, since these achieve their destructive power only upon nearing a shoreline.

 

Fig. 9

 

DAWT devices are at a semi-commercial level of development in Japan, with power ratings of the order of tens of kW. The most advanced projects have been developed by Kyushu University, who have studied several configurations, from single DAWTs to multi rotor systems, with a maximum tested power of 100 kW. In addition, tests on floating platforms were performed in Hakata bay.

 

Wind induced energy harvesting from aeroelastic phenomena

Air flow-induced vibrations of mechanical systems can be exploited to extract energy, when specifically designed to experience large-amplitude oscillations. The mechanical system has to be combined to work with suitable energy-conversion apparatus, such as electromagnetic or piezoelectric transducers. This type of technology will not be used for large-scale generation, but for applications where a small amount of autonomous power is required, e.g. wireless sensors or structural health monitoring. These energy harvesting devices have possible applications in urban settings and for energy harvesting at small and micro-scales. The LCOE for such devices will remain high compared with the much larger scale wind power generators, but for very small scale applications, may be cost effective.

 

The Vortex Bladeless Micro Wind Turbine

The startup Vortex Bladeless is developing a micro wind turbine shaped like a pole-like structure without blades or other moving parts. Vortex Bladeless relies on an aerodynamic phenomenon called vorticity, in which wind flowing around a structure creates a pattern of small vortices or whirlwinds. When these mini-whirlwinds get large enough, they can cause a structure to oscillate, and turbine converts this mechanical energy into electricity.

 

However, the individual structure will only oscillate at particular frequencies. The Vortex have developed a “magnetic coupling system” that results in broadening the range of frequencies and allows maximization of generation of energy. The microturbine can automatically vary rigidity and “synchronize ” with the incoming wind speed, in order to stay in resonance without any mechanical or manual interference.

 

The plus side is turbine’s ultra-slim silhouette that could enable it to fit into all sorts of tight spaces where larger turbines can’t, however the main point of contention is the cost effectiveness of micro wind turbines. The initial product line consists of two models, a 1-megawatt Gran and a 4-kilowatt Mini. France’s Eiffel Tower recently got a full on green makeover, including a pair of high visibility vertical micro wind turbines embedded in the tower itself.

 

Self-rising towers

The production of wind energy could increase with larger wind turbines on higher towers. Lattice structures could be more suitable for building taller wind turbine towers, even if there is a lack of very high cranes for erection. Self-rising lattice towers are suitable for horizontal axis wind turbines both in onshore and offshore applications, constructed by raising each tower subsection from the prior lower tower section. Their advantage is that there are no large cranes necessary for the installation of the tower. Tower subsections can be mounted and lifted to their final position with the aid of frames and the use of small size cranes and/or cables.

 

The two main EU projects on this self-rising concept are HyperTower and SHOWTIME. The HyperTower project aims to optimise the design of self-rising lattice towers that are ideal for onshore wind farms while the SHOWTIME project focuses on the design of hybrid towers. These hybrid towers are suitable for offshore locations where the bottom lattice part is connected to the tubular shell upper part by means of a transition piece that is carefully designed to sustain both wind and wave loads.

 

New materials for towers and support structures

Current wind turbine towers and support structures are constructed fromsteel and/or concrete. The steel is typically the same grade as used in the construction industry. Higher grades of steel can offer better structural performance (strength, buckling resistance) and lead to lighter structures. Hybrid solutions  using both steel and concrete and the use of alternative materials such as wood, aluminium  or especially composites, e.g. reinforced materials, or sandwich structures, can offer similar advantages in performance.

Innovative blade manufacturing techniques and materials

Blade manufacturing techniques may be relevant to the future performance of wind turbines and in terms of improving component lifetime. New solutions such as automated manufacturing, either involving fibre composite laminate laying  or additive 3D printing processes for both moulds and blades would allow technology-driven cost reduction in blade manufacturing, while reducing the uncertainty, i.e. manufacturing tolerance, in the process. Further and quicker adaptation to specific customer needs under the so-called ‘Industry 4.0’ paradigm would also become possible, as well as fast testing of new aerodynamic shapes. Sensors and actuators are expected to play a major role in future wind turbine blade manufacturing for enhanced monitoring and smart rotor designs, e.g. BTC.

 

An alternative material to fibre-glass wind turbine blades is fabric-based materials. They could significantly reduce production costs and weight of the blades. This technology uses tensioned fabric wrapped around a spaceframe blade structure, that is, a truss-like, lightweight rigid structure, replacing the current clam shell wind turbine blade design. The blade structure would be completely modified, allowing for easy access and repair to the fabric to maintain standard wind turbine performance.

 

New polyurethane based materials such polyurethane prepreg sheets and fibreglass/polyurethane foam preforms can be used to produce lighter, stronger and longer blades, compared to the current commercial epoxy-based versions. A key property of wind turbine blades is the inter-laminar fracture toughness. The incorporation of multi-walled carbon nanotubes into polyurethane composites can double the fracture toughness of epoxy blades

 

Carbon Fiber Composites for Blades

DOE’s Sandia National Laboratories, Oak Ridge National Laboratory, and Montana State University demonstrated the commercial viability of a novel cost-competitive carbon fiber composite material for use in wind turbine blades. The analysis found commercial viability and system-level benefits for using carbon fiber composites to reduce the overall cost of wind energy and manufacture long, slender wind turbine blades. The project revealed a 25% blade mass reduction when using carbon fiber spar caps compared to fiberglass. While wind manufacturers have historically avoided using carbon fiber due to its higher cost, the new textile-based carbon fiber material used for spar caps in this study cost 40% less than commercial carbon fiber — potentially enabling the broader adoption of carbon fiber materials in wind turbine blade design with the potential to reduce system costs.

 

Wind Farm

A wind farm is a group of wind turbines in the same location used to produce electricity. A large wind farm may consist of several hundred individual wind turbines and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other purposes. A wind farm can also be located offshore.

 

The wind farm technology has also become very sophisticated and efficient, world’s biggest offshore wind farm is to be built 75 miles off the coast of Grimsby, at an estimated cost to energy bill-payers of at least £4.2 billion. The giant Hornsea Project One wind farm will consist of 174 turbines, each 623ft tall generating 1.2 gigawatt  capable of powering one million homes.

 

 GE bringing industrial Internet to wind farms

General Electric Co. has announced a new wind farm technology that will improve output by 20 percent — providing the wind power industry with $50 billion in added revenue. “It’s a huge breakthrough for renewable energy and specifically wind power,” Bolze told the Times Union during a telephone interview. “The world wants more wind power. Same wind, 20 percent more electrical output. That’s huge.”

 

Steve Bolze, the CEO of GE Power & Water, said the new product — called the Digital Wind Farm — has been in development for the past 18 months and combines the company’s two-megawatt wind turbines with GE modeling software, sensors and the industrial Internet, which allows machines to exchange data, or “talk” to one another.

 

Integral to achieving all this has been the development of more precise, accurate, robust, and responsive wind energy forecasting algorithms, Grid-scale batteries built into the turbines and real-time wind turbine networking, and power management. Industrial internet communicates with grid operators, to predict wind availability and power needs, and helping to manage wind’s variability and provide smooth, predictable power.

 

Aquanis awarded $3.5 million funding from US DOE for improvements in wind technology

Aquanis  announced in Nov 2018  that it was awarded $3.5 million in funding from the U.S. Department of Energy’s (DOE’s) Advanced Research Projects Agency-Energy(ARPA-E), which will be used to develop a control system that will allow wind turbines to react more quickly to changes in the wind. The funding will be used to develop a segmented active load control system featuring the Company’s electrical blade-mounted actuators that modify the local flow over the surface of the blades without using mechanical components (no moving parts).

 

“We are thrilled to have been chosen for this highly competitive ARPA-E award” said Aquanis Founder and CEO Neal Fine. “Aquanis is committed to helping the wind industry continue the historic improvement in turbine technology, which is key to reducing the cost of wind energy and increasing wind penetration in the grid energy market. Our selection by ARPA-E confirms that we are working with a great team on an important and challenging problem.”

 

The cost of wind energy can be reduced by deploying larger, more efficient, and more durable wind turbines. In order to build such wind turbines, designers must find a way to mitigate unsteady loads on the turbine blades, caused by wind gusts, turbulence and other changes in wind speed. All of the remedies tried to date have moving parts, and are costly and complex to implement. Aquanis is developing a new technology that can address the problem with no moving parts and minimal blade modifications. In addition to introducing new innovations to advance the Company’s actuator technology, the team will develop an integrated design approach to maximize the impact of segmented active load control on the cost of energy.

 

The World’s First Floating Wind Farm Is Now Producing Energy

 Floating wind farms far out at sea hold a lot of promise for future energy generation. Wind turbines  can be packed too densely far out in the sea than  on land or near the coast,  as the drag effect  that causes less wind to flow  is less pronounced far in the sea. That means it’s possible to extract six megawatts per square kilometer rather than the 1.5 achieved on land using the same turbines.  Analysis , to the extent that three million square kilometers of floating wind turbines could supply the entire world’s current energy demand.

Hywind Scotland, situated in Buchan Deep, is the world’s first floating wind farm, with its five six-megawatt turbines now generating electricity. On shore, a one-megawatt-hour lithium battery also helps smooth its potentially erratic supply of electricity to the grid. It’s also a concept that’s catching on elsewhere, with a scheme similar to the Scottish project under consideration in California.

The project, which is a collaboration between the Norwegian oil firm Statoil and Masdar Abu Dhabi Future Energy, makes use of turbine towers that are 253 meters tall, with 78 meters of that submerged in the North Sea. Each tower is tethered using three cables that are anchored to the seabed.

Buchan Deep project cost a total of $263 million to complete. It currently receives $185 per megawatt-hour of subsidies from the British government, on top of the $65 per megawatt-hour it earns for the wholesale price of the electricity it creates. In other words, it’s damned expensive. Statoil says that it hopes floating wind farms could produce energy for between $50 and $70 per megawatt-hour by 2030.

Defense Deployable Disaster Wind Turbine

The WETO-funded Defense Deployable Disaster Wind Turbine project evaluates the technical and market potential for rapidly deployable wind energy systems to meet the energy needs of defense and disaster response activities. A 2020 report found there is a significant opportunity for wind turbines to provide on-site power and overcome the risks and limitations of existing diesel-powered generators used to support foreign defense missions or humanitarian activities, such as disaster response. The report’s analysis suggests that low wind speed optimized and rapidly deployable wind turbines, when integrated with battery storage, could be used to offset 80% of diesel generator use at certain forward operating bases.

UK seeks to reduce wind farm impact on air defence radar system

The UK Ministry of Defence’s (MoD) Defence and Security Accelerator (DASA) has awarded contracts to five companies in Oct 2020  to develop technologies that will eliminate offshore wind farms’ interference on air defence radar system. The contracts follow an investment worth £2m by the UK Government. The companies are Thales, QinetiQ, Saab, TWI and Plextek DTS. The innovation competition is led by the MoD’s DASA on behalf of the Department for Business, Energy and Industrial Strategy (BEIS), the Royal Air Force (RAF), and the Defence Science and Technology Laboratory (Dstl). Defence Minister Jeremy Quin said: “We want more offshore wind farms to help deliver our ambitious environmental agenda while retaining the protection that radar provides.

 

Thales will partner with the University of Birmingham and SMEs to develop surveillance to reduce the wind farm ‘clutter’, while Saab will use artificial intelligence and doppler filtering to develop a radar mitigation system. QinetiQ will develop two proposals. In the first method, it will use new materials to prevent the distortion of the radar, while the second method will develop radar-absorbing materials that can be installed on offshore wind turbines. TWI will be responsible for the development of new methods to create conductive coating that will absorb radar for turbine blades, in collaboration with the Centre for Metamaterial Research and Innovation of University of Exeter.

 

Cybersecurity Roadmap

More than 50,000 wind turbines with a combined capacity of over 100 gigawatts operate in the United States, creating a serious need to protect wind infrastructure from cyberattacks. With support from its national laboratories, WETO published the Roadmap for Wind Cybersecurity, which outlines the increasing challenges of cyber threats to the wind industry, its technologies and control systems, and present activities and best practices that the wind industry can use the improve cybersecurity.

 

References and resources also include:

https://www.sciencedirect.com/science/article/pii/S1364032119304782

https://www.airforce-technology.com/news/uk-seeks-to-reduce-wind-farms-impact-on-air-defence-radar-system/

https://www.engineering.com/story/the-future-of-wind-turbines-comparing-direct-drive-and-gearbox

https://cleantechnica.com/2021/01/05/2020s-top-wind-energy-rd-achievements/

 

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