When measuring the economic benefits of wind turbines, the cost of energy COE, that is, the cost per kilowatt-hour, is generally used as the evaluation index. As the name suggests, the unit's kWh cost is the ratio of the total cost of the unit to the power generated.
For example, for example, the cost of a 2MW wind turbine (parts, construction, maintenance, etc.): X yuan
In the design life of the wind turbine of 20 years, the total The power generation capacity is: Y kilowatt hours.
The cost of electricity per kilowatt hour is X/Y
The largest one is 5MW, which is available in Denmark and one in China. Generally, 2MW, 1.5MW, or smaller 0.8MW are used in China.
Electrical power calculation formula: P=W/t =UI.
In a purely resistive circuit, according to Ohm's law U=IR and substituted into P=UI, we can also get: P=I2R=(U2)/R.
In dynamics: Power calculation formula: P=W/t (average power); P=FV; P=Fvcosα (instantaneous power).
Extended information
When the wind turbine generates electricity, it must ensure that the output frequency is constant. This is very necessary for both wind turbine grid-connected power generation and wind-solar hybrid power generation. ?
To ensure that the frequency of wind power is constant, one way is to ensure a constant speed of the generator, that is, a constant speed and constant frequency operation mode. Because the generator is driven by the wind turbine through the transmission device, this This method undoubtedly requires constant speed of the wind turbine, which will affect the conversion efficiency of wind energy.
Another way is to change the generator speed with the wind speed and ensure the frequency of the output electric energy to be constant through other means, that is, variable speed constant frequency operation. The wind energy utilization coefficient of the wind turbine is related to the blade tip speed ratio (the ratio of the linear speed of the impeller tip to the wind speed). There is a certain blade tip speed ratio that makes Cp reach the maximum value.
Baidu Encyclopedia-Wind Turbine