http://www.iflscience.com/environment/denmark-breaks-its-own-world-record-wind-power-generation-2015
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http://www.iflscience.com/environment/denmark-breaks-its-own-world-record-wind-power-generation-2015
Posted from WordPress for Android
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Tomi Engdahl says:
Germany had so much renewable energy on Sunday that it had to pay people to use electricity
http://qz.com/680661/germany-had-so-much-renewable-energy-on-sunday-that-it-had-to-pay-people-to-use-electricity/
On Sunday, May 8, Germany hit a new high in renewable energy generation. Thanks to a sunny and windy day, at one point around 1pm the country’s solar, wind, hydro and biomass plants were supplying about 55 GW of the 63 GW being consumed, or 87%.
Power prices actually went negative for several hours, meaning commercial customers were being paid to consume electricity.
Last year the average renewable mix was 33%, reports Agora Energiewende, a German clean energy think tank. New wind power coming online should push that even higher.
Critics have argued that because of the daily peaks and troughs of renewable energy—as the sun goes in and out and winds rise and fall—it will always have only a niche role in supplying power to major economies. But that’s looking less and less likely. Germany plans to hit 100% renewable energy by 2050, and Denmark’s wind turbines already at some points generate more electricity than the country consumes, exporting the surplus to Germany, Norway and Sweden.
Tomi Engdahl says:
Distributed Wind Power on the Rise
PNNL’s annual report tracks rapid growth.
https://www.powerelectronics.com/alternative-energy/distributed-wind-power-rise?NL=ED-003&Issue=ED-003_20180830_ED-003_112&sfvc4enews=42&cl=article_1_b&utm_rid=CPG05000002750211&utm_campaign=19591&utm_medium=email&elq2=387fc062f16347b28d8c8e0400caae53
The U.S. Department of Energy’s Pacific Northwest National Laboratory has issued its annual report on distributed wind capacity, revealing that large installations of distributed wind power almost doubled in 2017.
Distributed wind power is localized, so the power is generated near where it will be used rather than originating in remote commercial wind farms and getting sent to load centers over long transmission lines. Distributed wind farms generate power for homes, farms, businesses, and other locations where the power is typically consumed onsite, or on the local distribution system to meet energy demands. Facilities can range from a 5-kW turbine powering a home to a few multi-megawatt turbines sending electricity to several industrial sites on the same distribution system.
Tomi Engdahl says:
5 Wind Turbines which Failed (Enviromental friendly?)
https://www.youtube.com/watch?v=MVHzfUWul2Y
Nearly 120 wind turbines catch fire each year, according to a research – ten times the number reported by the industry. The researchers claim that out of 200,000 turbines around the world, 117 fires take place annually – far more than what is reported by wind farm companies.
Tomi Engdahl says:
Haku
Wind Turbine Tour
https://www.youtube.com/watch?v=8wK1qmRv_l8
Tomi Engdahl says:
Wärtsilä Offshore Wind Farm Solutions
https://www.youtube.com/watch?v=0lHpwgx15E4
Tomi Engdahl says:
Approximately 140,000 to 500,000 birds die annually from collisions with wind turbine blades in the US. This could reduce deaths by 70 percent.
Painting Just One Wind Turbine Blade Black Could Dramitcally Decrease Bird Deaths
https://www.iflscience.com/environment/painting-just-one-wind-turbine-blade-black-could-dramitcally-decrease-bird-deaths/
Approximately 140,000 to 500,000 birds die annually from collisions with wind turbine blades in the US, according to the US Fish and Wildlife service.
Now, researchers think they may have found a way to lessen these collision deaths in the most simple way possible after a small-scale, nine-year study at the Smøla wind farm in Norway. All it takes is a touch of black paint. By painting just one blade black, the researchers report they have managed to reduce bird deaths from wind turbines by over 70 percent.
Reporting their findings in Ecology and Evolution, Roel May and colleagues suggest that a painted blade can increase the visibility of the spinning turbines and prevent birds from getting struck. The research found a significant reduction of bird carcasses below painted wind turbines when compared to numbers prior to painting and also compared to neighboring turbines that weren’t painted. They found that although the control turbines saw an increase of carcasses over the years, those that were painted saw a reduction.
Tomi Engdahl says:
https://etn.fi/index.php/13-news/14117-uusi-turbiini-voi-mullistaa-tuulivoiman
Tomi Engdahl says:
Wind, solar fulfill 10% of global electricity demand for first time
Curb your enthusiasm – coal-fired power went up too
https://www.theregister.com/2022/09/29/wind_solar_power_electricity_record/
Tomi Engdahl says:
https://www.talouselama.fi/uutiset/sahkoa-aurinkopaneeleita-halvemmalla-tama-uudenlainen-lavaton-tuuliturbiini-on-tarkoitettu-talojen-katoille/69f47dde-bc57-421d-bb7d-66e247d07e77#Echobox=1666020204
Tomi Engdahl says:
https://hackaday.com/2023/08/30/converting-wind-to-electricity-or-the-doubly-fed-induction-generator/
Tomi Engdahl says:
https://www.researchgate.net/figure/Wind-speed-distribution-and-power-curve-of-a-23MW-wind-turbine_fig2_270586944
Tomi Engdahl says:
Converting Wind To Electricity Or: The Doubly-Fed Induction Generator
https://hackaday.com/2023/08/30/converting-wind-to-electricity-or-the-doubly-fed-induction-generator/
Type 1 Wind Turbines: Fixed Speed
The type 1 wind turbine, sometimes referred to as a fixed-speed turbine, actually doesn’t concern itself much with dealing with short, transient changes in wind speed. Using the inherent properties of an induction generator solves this problem effortlessly. In this configuration, the output of the generator is connected directly to the grid, and the grid’s inertia keeps it mostly at the correct rotational speed. When a gust arrives, the generator will simply “slip” a little past its synchronous speed, and will then recover back to a normal state after it has absorbed the gust. If the gust is too much, turbines in this category may also employ an electric “brake” which dumps the excess energy into a resistor bank or equivalent device, slowing the turbine slightly.
The benefits of induction machines in this regard are largely simplicity and cost; generally only small (or old) wind turbines use simple induction generators like this now due to their higher electrical losses compared to other generator types. There aren’t just electrical losses to consider, either. The aerodynamic losses of operating at a fixed speed can be significant when a lower or higher rotor speed might otherwise be more efficient. Other noteworthy downsides include the inability to provide reactive power to the grid as well as being extremely sensitive to voltage and frequency variations on the grid, meaning they more easily trip offline for electrical transients.
Type 2 Wind Turbines: Variable Speed
The type 2 wind turbine, also called a variable-speed turbine, attempts to solve some of these problems. A device called a converter is integrated into the turbine to precisely control the magnetic field within the generator’s rotor. This means that the turbine can change how much slip there is within the generator and, as the name implies, can allow the turbine to operate at a more aerodynamically efficient rotational speed even as average wind speed changes. Not only does this improve the electrical and aerodynamic efficiencies, but by varying the rotor’s magnetic field the turbine can provide or absorb reactive power from the grid.
There are some downsides, though, largely with respect to complexity and cost. To control the magnetic field in the rotor a slip ring is required, which can be a maintenance-intensive piece of equipment compared to the type 1 turbines. The converter itself is also an extra maintenance item, and there are some other additional components that add costs as well such as thyristors which help the generator smoothly connect to the grid.
the type 2 turbine largely replaced the type 1 turbine for large-scale energy production in new wind farms around the late 90s and early 00s.
Type 4 Turbines: Huge Inverters
In order to save the most interesting for last, let’s skip ahead a bit and discuss the Type 4 turbine layout. Type 4 turbines span a wide array of seemingly unrelated machines, but they all have one thing in common: the electrical output from the generator is “fully inverted” meaning that 100% of the generated energy passes through a power electronics system which converts it to grid voltage and frequency. Any wind gusts that come along that aren’t absorbed by the turbine’s pitch system are simply handled by the power electronics. These converters are similar to the converters used in the type 2 machines except that the power electronics systems must be massive to handle the full rated power of each turbine’s generator.
Despite the huge cost and complexity of large power electronics systems, this opens up a huge number of other design options. For example, essentially any generator can be used and operated at any speed. For AC generators this means that the turbine no longer needs control of the rotor’s magnetic field like a type 2 turbine would; even permanent magnet generators can be used in these setups. AC generators can often require two stages of converters though, one to turn the generated AC to DC and another to take the DC and convert it to grid voltage and frequency. However, it’s also possible to skip the first conversion step by using DC generators directly
With type 4 turbines, since the energy all passes through an inverter it makes essentially no difference how much or what kind of electrical energy is produced. Essentially the only downside of the type 4 machine is the huge cost of the power electronics
Type 3: Doubly-Fed Induction Generators
Combining all of the perks of the type 2 machine with some of the perks from a type 4, we come at last to the doubly-fed induction generator, also known as a DFIG (pronounced “dee-fig”). It gets this name because, unlike the type 2, both the stator and rotor are capable of sending energy to the grid. During startup or during periods of low wind speed, called “sub-synchronous speed”, the rotor converter draws power from the grid to drive the magnetic field on the rotor. However, above the generator’s natural synchronous speed, called “super-synchronous speed”, the process reverses and the rotor is able to generate energy instead, sending it back through the converter to the grid. At all points in the turbine’s operation, though, the magnetic field of the rotor is meticulously controlled to keep the generator at the ideal rotational speed.
Not only does this allow for control over the generator’s power factor (meaning that DFIG turbines can provide or consume reactive power and support the grid like a type 2 turbine) and allows for much more robust ride-through of low voltage events on the grid, this also means that a much smaller converter is needed since only the rotor’s power has to be sent through the power electronics.
The DFIG offers an elegant solution to many problems with wind turbine design, although like other types of turbines handling wind gusts is only part of the story for why a particular configuration might be used. It’s not a technology seen often outside of the wind industry, either, since precise control over a generator is generally not needed when the input speeds are more constant than wind allows. But DFIGs do see some use in pumped storage facilities