The key factor contributing to the high cost of wind power generation is that the cost of wind turbine units accounts for more than 70% of the investment in wind farms. This is also one of the important reasons why wind power cannot compete directly with thermal and hydropower and must introduce government subsidies.
Chinese patent application 201010571789.8, Energy-Enhancing Wind Turbine System, is a new technology that increases the power generation of existing synchronous wind turbine generators at a very low cost, and can obtain more wind energy from various wind speeds, thereby effectively reducing wind power costs and improving the market competitiveness of wind power.
After several years of research and development on wind turbine energy enhancement technology, we have now completed the industrialization of energy enhancement technology for synchronous wind turbine generators.
The energy enhancement mechanism of synchronous wind turbine generators is:
In a light breeze, the unit can reduce the cut-in wind speed, start generating electricity earlier, and obtain more energy from the breeze.
During medium wind speeds, the generating units increase power generation by improving generator efficiency, thereby gaining greater economic benefits from power generation.
At rated wind speeds and above, the unit can leverage its advantage of increasing the rated power of the generator to maximize its maximum output power and obtain the greatest economic benefits.
The new technology can increase the generator's output power by about 15% while maintaining the same total losses (iron and copper losses). This results in a higher actual efficiency for the generator compared to before the technology was implemented. In other words, this power enhancement technology can potentially increase the rated power of a generator by 15% at zero cost.
The generator sets used in existing wind farms mainly fall into two categories: asynchronous and synchronous. Asynchronous generators come in two types: those with a power output below 1MW are older, fixed-speed squirrel-cage turbines, which are being phased out; while most are variable-speed doubly-fed turbines with a power output of MW or higher. Energy enhancement technologies for asynchronous wind turbines are under development; this article only recommends energy enhancement technologies for synchronous wind turbines.
As is well known, there are more and more advanced varieties of synchronous wind turbines than asynchronous ones among large-scale turbines. They are mainly direct-drive turbines in the MW range, including low-speed permanent magnet direct-drive turbines, low-speed excitation direct-drive turbines, and medium-speed semi-direct-drive synchronous turbines. In addition, there are also various models such as high-speed permanent magnet turbines or high-speed exciters with gearboxes and brushless exciters.
Synchronous wind turbine generator sets that can be upgraded using this energy-enhancing technology include:
E-series excitation direct drive units from the German company Enercon: 400kW, 600kW, 2.5MW, 7.5MW, etc.
Permanent magnet direct drive motors from the German company Siemens: 3MW, 3.6MW, etc.
High-voltage permanent magnet direct-drive generator products from ABB Sweden.
Domestic products include:
Goldwind Technology's permanent magnet direct drive products include 1.2MW, 1.5MW, 2MW, 2.5MW, 3MW, and 6MW models.
Xiangdian Wind Power's permanent magnet direct drive products: 2MW, 5MW, etc.
Products from CNR Wind Power and CNR Zhuzhou Electric: 2.5MW permanent magnet direct drive, etc.
Guangxi Yinhe Aivandis' permanent magnet direct drive products: 2.5MW and others.
Huachuang Wind Power's permanent magnet direct drive products include 1.5MW and 2.0MW models.
CNR Wind Power's high-speed permanent magnet: 1.5MW and other products.
Shandong Changxing Wind Power Technology's high-speed brushless excitation products include 850kW, 1.5MW, and 2.1MW models.
Shandong Luko Wind Power Equipment's direct drive wind turbines include products such as the 1.5MW direct drive wind turbine.
Shanghai Wande Wind Power's permanent magnet direct drive products include 1.25MW, 1.5MW, and 2MW models.
Jiangxi Maide Wind Power's permanent magnet direct drive products: 1.5MW and others.
Jiangxi Lide Wind Power's permanent magnet direct drive products: 1MW, 2MW, etc.
Guodian United Power's electro-hydraulic/electromagnetic coupling synchronous power generation products include 1.5MW and 3MW models.
Nordwin's electro-hydraulic coupling synchronous power generation products include 800kW, 1.2MW, and 1.5MW.
Mingyang Wind Power's SCD compact semi-direct drive medium-speed permanent magnet: dual-blade 3MW and other products.
In my country, synchronous generators account for approximately 25-35% of the total power output of wind farms, while in newly built wind farms, this figure may be 30-40%. In Germany, it is said that synchronous direct-drive generators account for over 50% of newly built wind farms.
Currently, we can use this technology to enhance the energy output of various synchronous wind turbine generator sets. For example, existing synchronous wind turbine generator sets in wind farms or by users can be retrofitted using this technology to improve the economic benefits of the equipment. Enterprises only need to invest a small amount of money to implement the retrofit. If the minimum retrofit cost is 1, the economic benefits of the additional energy captured in light winds, the increased energy gained in normal wind speeds due to improved generator efficiency, and the increased overload capacity at rated wind speeds and above due to increased rated power, will result in an annual increase in power generation that is approximately 50 to 100 times the retrofit cost. In other words, the retrofit cost can be recovered in an average of about 4 days to a week. If the remaining lifespan of the wind turbine is calculated to be 15 years, the ratio of economic output to retrofit cost will be as high as 750 to 1500 times. However, considering that the design limits of the wind turbines, mechanical systems and converters of existing units do not allow for overload, and that rated and above wind speeds can only operate within the original power limits, the input-output ratio may be reduced to about 500 times. However, at that time, the generator efficiency will still be higher than that of the original units, and the new system improved by this technology can still obtain economic benefits from generating more electricity.
For wind turbine manufacturers, the economic benefits of this technology are also substantial. For example, taking Siemens' SWT-3.6-107 3.6MW permanent magnet direct-drive wind turbine as an example, the Siemens 3.6MW generator improved with this energy-enhancing technology is equivalent to an upgrade to 4.1MW, increasing the rated power by 500kW. Based on the relatively low wind turbine price of €650/kW in the European market, the increased sales revenue per unit is approximately €325,000. Since the rated power of the unit is largely limited by the generator, while the increased costs for blades, shafts, mechanical systems, and converters may be less significant, the additional costs for the wind power equipment manufacturing industry are not high, while the benefits are substantial, making its economic benefits considerable.
Taking Goldwind Technology, China's largest manufacturer of permanent magnet direct-drive wind turbines, as an example, using this technology, the rated power of the original unit can be increased to 2.9MW with only a slight increase in cost. Even at the current lowest selling price of 3850 yuan/kW, each unit can generate an additional 1.44 million yuan in sales revenue. Upgrading 5MW or 6MW units to 5.7MW or 6.9MW units can further increase revenue by 2.69 million yuan or 3.46 million yuan per unit. While the rated power of the unit is greatly affected by the generator, upgrading the wind turbine, mechanical system, and converter also requires certain costs. However, regardless of these factors, the breadth of application and the economic benefits of this technology are unparalleled by any other wind power technology currently available domestically or internationally.
Small generators are mostly permanent magnet synchronous generators, and this technology can also be used to improve power generation capacity, obtain more electrical energy, and increase power generation revenue.
This technology is very mature and can be licensed to qualified wind power companies, including both domestic and foreign companies in the power generation and manufacturing industries.
