Hidden troubles of wind turbine quality (4)

Prob1em III: Ouality of tower flange do not experJence rigorOus test of time. Over the last two year, many flange manufacturing plants jumped out and sprang up all over the pIace. Many enterprises do not have the process management, vertical axis wind turbine inspectlon and test capabilities of production, coupled with the insufficiency of product acceptance of tower flange usersl it does not show the reaI quality issues of product. In addition, generator set operation has not yet reached the high-incidence season of machinery equipment failures within over two years, greater problems and challenges may still lay ahead. Tower flanges currently in use have occurred several major quality problems, such as wind turbine flanges supplied by a foreign wind turbine flange manufacturer occurred low--temperature impact performance probIems, caused a large number of return and had to bear the huge compensation. For the settlement of hidden qua]ity troubles brought by vicious competition in the market of wind turbnie flange, I believe, fIrst to accel-erate the formulation and promulgation of national standards of " Wind Power Generator Set Flange" by industrial association, and regu1ate processing and manufacturing, inspection rules and testing methodsI second, raise market access threshold and proposes hjgher requirements to equipment capacity, inspection level and qualif1cation of wind turbine flange manufacturers and supp1iers at the tender, and assess whether the suppliers have sufficient resource Supporting capacity, third, tower flange users should understand the reasonab1e market cost price in advance and do not accept the Iowest quoted price at the tender and tender evaluation in order to make every effort to create a platform for fair competition not only depending on quoted price but aIso on their demonstrated potential to tower flange manufacturers and suppIiers, fourth, tower flange users should strengthen acceptance standards through occaslonal sampIing and on -site random sampIing to urge the manufacturers to improve product quality, fifth, take corresponding supplier management approach to ensure stabIe and healthy development of supply chain, establish strategic cooperative relations with Suppliers, avoid vlcious competition and take favorabIe costs contro1 capability as weI1 as stable and re1iable product quality of tower flange manufactures and Suppliers as the cornerstone of biIateral cooperation. In light of the hidden quality troubles of tower flanges currently appear in the industry due to vicious competition, as a member in the industry, l propose the said personal views with the purpose of exchanging view with you and Joint discussion. I hope it could heIp to solve the problem of cut--throat competition current1y existing in the industry and make contribution of heaIth and rapid deveIopment of the industry.

Hidden troubles of wind turbine quality 3

Problem ll :Wind turbine Tower flange manufacturing belongs to intensive equipment manufacturing with relatively larger initial investment.For example, it must ensure the forging ratio no less than 4.5 in the forging process in order to make wind turbine tower flange meet higher standard requirements at strength, pIasticity, fatigue resistance and Iow--temperature impact toughness which requires Sufficient forging equipment capacity. Forging press must be over 3000T-4000T, ring ro1l must be over 5M, but the price of such an equipment host device is generally between 10 mi1lion and 20 mlllion. It is hard for small enterprises to meet such equipment level due to limited capita1 strength, therefore, they can only lower the standards, manufacture in a rough and slipshod way, use small equipment to do the tough work which does not guarantee the quality and cause many troubles and hidden dangers of accidents to the product and vertical axis wind turbine.

Hidden troubles of wind turbine quality 2

Problem l. Production capacity surplus shall inevitably lead to the price war of wind turbine set similar to that of color TV and refrigerator, therefore, resulting in the price and profit decline of wind power manufacturing products. Take tower flange for an example, the average profit margin of products is currently just about 5%. For some excellent enterprises, they can also achieve the development of enterprises with certain production scale and reJatively high market share through technoIogy innovation and favorable cost control abilityI however, for the small scale enterprises got involved late without independent research and development capabilities, they can only earn profits reIying on loosing quality control and process management, and adulteration. Such as raw material control, tower flange is the important Supporting and connecting component for wind power generator set. It suffers from the effects of bitter cold or torrid heat and extreme temperature difference as weIl as the impact of complicated wind alternating load, therefore, it must seIect steel ingot or continuous casting round billet after refining and vacuum degassing but not continuous casting sIab for raw materials since defects of continuous casting slab are normally at the middle Iayer of the thickness direction and hard to remove after forgjng and heat treatment. AIthough using continuous casting slab reduces the costs, it buries hidden troubles of quality and safety for the long-term stable operation of generator set. For another example, not strictIy perform heat treatment process and shorten heating -up and heat preservation time in order to reduce heat treatment costs, although costs falls but it makes the forged thick grain thin through heat treatment, gets small uniform pearlitic structure and e1iminates the stress, which makes it hard to meet requirements of mechanical properties, results in internal stress remaining in the tower flange constantly releasing over time, makes the deformatIon of fIange, may leads to local concave or convex of tower and brings risks to normal run of the generator set.

Hidden troubles of wind turbine quality 1

With China’s sustained economic development, huge demand for electricity power has spurred the rapid development of the entire energy industry, and our vast wind resource reserves have provided sufficient space for the large -scale development of wind turbine power industry. Based on the incomplete statistics, our wind turbine power equipment output of the first half of 2009 has reached 4.27 million kW, representing an increase of 135.7%. However, wind power projects of 12.3 million kW have been approved to construct at the same time within the country, which may be followed by production capacity Surplus. As showed in" 2009 –2012 lnvestment AnaIysis and Prospects Forecast of China's Wind Power lndustry" issued by China Investment ConsuIting Co., Ltd.: there are currently over 70 wind power machine manufacturing enterprises in total in Our country, more 50 fan manufacturing enterprises, up to 100 tower manufacturlnq enterprises, and about 30 flange manufacturing enterprises As calculated by enterpr1se production capacity, it has been far more than market capacity and wind turbine market has been transformed from seller’s market to buyer's market. Fierce vicious competition has been carried Out among manufactures in order to obtain orders, which brought considerabIe risks and hidden troubles for product quality.

How does the wind turbine produce electricity?

1.The wind passes over the blades creating lift (just like an aircraft wing) which causes the rotor to turn.
2. The blades turn a low-speed shaft inside the nacelle: wind energy is converted into rotating, mechanical energy.
3. In most wind turbines, mechanical energy is channelled to a gearbox. The gears connect the low speed shaft of the rotor with a high speed shaft that drives the generator. Here the slow rotation speed of the blades is increased to the high speed of generator revolution (ratio: 1:100). Some wind turbines do not contain a gearbox and instead use a direct drive mechanism to produce power from the generator.
4. The rapidly spinning shaft drives the generator to produce electric energy.
5. Electricity from the generator (around 700 V) goes to a transformer which converts it to the right voltage for the distribution system (33,000 V).
6. The electricity is transmitted via the electricity network. The nacelle is rotated automatically to follow the changing direction of the wind so as much energy as possible is captured.
Wind turbines generate energy at wind speeds of 4-25 metres per second. When turbines are generating electricity, the rotor speed will be 9-19 revolutions per minute, depending on the wind speed and the turbine type. If the wind reaches speeds over 25 metres per second, which happens rarely, the wind turbine stops because such speeds place too much strain on the turbine’s components. In the early days of modern wind power, wind turbine rotors were 20 metres in diameter and had a capacity of 20-60 kW. Ten years later, the machines had a capacity of 500 kW, and today offshore turbines can reach up to 5 MW or more, spanning 120 metres – longer than a football field. The average size of onshore turbines being manufactured today is around 2.5-3 MW. One 2.5 MW onshore turbine produces power for over 1,500 EU households.The larger blade lengths capture more wind and therefore produce more electricity and reduce the cost of power generation.

Offshore wind power market draw great attention

It is learned recently that Chinese Renewable Energy Industries Association, Global Wind Energy Council and Shanghai international Exhibition Co., Ltd of the Shanghai Branch of China Council for the Promotion of international Trade will jointly hold the "2010 Shanghai international Off shore Wind power (wind turbine) and Wind power (wind turbine) industrial Chain Conference and Exhibition", which is the first professional platform focusing on offshore wind power (wind turbine) market in Asia, in Shanghai during June 7--9, 2010. The activity will provide enterprises with the opportunity of meeting, exchange and display in terms of design, installation and management of offshore wind power (wind turbine) projects and R&D and supporting of offshore wind turbines. It aims to promote the sound development of China's offshore wind power (wind turbine) market and wind power (wind turbine) industrial chain. The exhibition received great support from National Energy Administration, Shanghai Municipal Development and Reform Commission, Shanghai Municipal Commission of Economy and informatization, Jiangsu Development and Reform Commission, Zhejiang Development and Reform Commission, Shandong Development and Reform Commission, Fujian DeveIopment and Reform Commission and Guangdong DeveIopment and Reform Commission. Li Junfeng, Secretary General of Chinese Renewable Energy industries Association, said that, "The activity is still at an early stage, but we are confident that it is a prospective platform and will have a sound development momentum." Arthouros Zervos, Secretary General of Global Wind Energy Council, said that, "Without the 70% localization rate for wind power (wind turbine) equipment (wind turbine), more advanced wind power (wind turbine) technology will drive stratght in China and make the competition even more fierce. This activity can build an international exchange and cooperation platform in this respect."

Future of wind power looks better than ever

The Global Climate Summit in copenhagen failed;However,the era of wind energy has already begun: European wind farms currently feed approximately 78,000 megawatts of output into power grids.that figure is expexted to grow by 15 percent with an additional 13,000MW slated for installation in 2010.Other continents are following suit.The American Wind Energy Association estimates that North America will again reach the record level of 2008, with the US installing 8,500 MW of new capacity and even double-digit gigawatt growth starting in 2011. Canada is developing a market with an annual figure exceeding 1,000 megawatts. In Asia, China’s newly installed capacity is estimated at seven megawatts and upwards, followed by India. The diversity of market is also reflected in the wide range of manufacturers and wind turbines offered within the wind turbine market. Manufacturers can publish their data at no charge. At present, the large offshore and repowering markets are scarcely represented in all short-term forecast.The future of wind power looks better than ever.