Microwaves or top wind on the roof, as a rule, are described, as a rule, get a bad rap; and it is deserved. As for the return on investment, the wind on the roof is probably one of the worst investments in renewable energy that you could make. Unfairly concentrated in this unproductive class of wind power is a home-made wind generator.
To illustrate this point, I will compare the cost per kilowatt-hour (kWh) of electricity generated by the small Swift wind turbine to a typical home-built generator, about two times lower than that of the Swift. As for wind turbines, the size is determined by the length of the propeller. The length of the propeller determines the "coverage area", which is akin to the collector area of the solar panel. The larger the area of coverage, the more energy is produced.
Once you know the average wind speed at a given location and the length of the propeller, you can estimate the monthly power in kWh. Multiply by the number of months it is expected that the turbine will continue, and divide the result by the cost of the turbine. The amount in which you find yourself is the cost per kWh for the entire lifetime of the turbine.
Wind speed determination
The height of an average house is about 15 feet or 4.5 meters. Using this information, I looked at the Atlas of Wind Energy Resources in the United States for average annual wind speeds at this altitude in Massachusetts. The average wind speed I came up with was 8.2 miles per hour.
Definition of monthly kWh production
Swift turbine: based on a 8.2 mph wind speed and a 7-inch Swift turbine turbine, its monthly capacity will be around 32 kWh or 7.680 kWh over a 20-year useful life. The predicted service life of this turbine comes from the manufacturer. Personally, I think this is a bit optimistic, but for simplicity I will not argue.
(A quick note on how I came up with a 32 kW / h figure. Hugh Piggot, a renowned wind power specialist, developed a formula that uses wind speed and foot length to estimate monthly kWh production for a turbine of any size. production of kWh, which everyone can use.
Now, to the home turbine. At 8.2 mph, winds with a smaller 4-inch turbine engine generate about 10.6 kWh per month or 2544 kWh for 20 years. Since there are no statistics on the expected lifetime of the domestic turbine, I will correct the discrepancy in the next step.
Turbine cost
The cost base for this comparison is intended only for the turbine. Fast turbine data for $ 10,000 to $ 12,000, so I’ll be counting on $ 11,000. The deduction for a 30% energy tax credit leaves the cost price of $ 7,700.
An example of a wind turbine used for this article costs about $ 100 to build. As I just mentioned, there are no predictions of life expectancy for the house, so I expect a replacement every six or seven years for a total value of $ 350.
Final answer
With a small simple separation, we can find out the cost per kWh for the entire lifetime of the turbine.
Fast turbine: $ 7,700 / 7,680 (kWh) = $ 1.00 per kWh.
Internal turbine: $ 350 / 2,544 (kWh) = $ 0.14 per kWh.
Remember that the home model is equipped with 4 supports. If you increase the length of the propeller from 4 to 5, the magic of physics increases the life span of kWh to 3960 kWh and reduces the cost per kWh to $ 0.09. Now it is eco-nominal.
