Last Updated on February 10, 2023 by Mary Pressler
A Quick History of Windmills
In simple terms, a wind turbine can be described as a large electric fan operating in reverse. Just like a fan converts electricity into air movement, a wind turbine generates electric power when exposed to moving air at an adequate speed. When used in utility-scale installations, wind turbines and solar panels can now achieve the lowest generation costs in the world, even below coal power plants.
Humanity has been using mechanical windmills for hundreds of years, and there is evidence of basic wind engines in Ancient Greece. Historically, the main applications of windmills have included water pumping and grain milling.
- Traditional windmills were largely displaced by steam engines during the Industrial Revolution, and later by electric motors, but now they are making a comeback in the form of wind turbines.
- Fully mechanical windpumps are very popular in many parts of the world, especially in remote locations, since they are reliable and self-sufficient.
The first modern wind turbine was built in 1887 by James Blyth, a Scottish engineer. The technology quickly became popular, and there were many wind turbines generating electricity in North America, Europe and Australia by the 1930s. These were much smaller than the current megawatt-scale turbines, and they were used mostly in farms and other remote locations with no power grid coverage. Nowadays, there are giant wind turbines with a capacity of over 10 megawatts each (10,000 kW).
Why Are Modern Wind Turbines So Large?
As of December 2021, the largest wind turbine model is the Siemens Gamesa SG 14-222 DD, designed for offshore operation. The rotor has a diameter of 222 meters (728 feet), and it sweeps an area of 39,000 square meters (419,792 sq. ft.). One of these wind turbines can generate enough electricity for 18,000 homes, and there are plans to use 30 of them to fully power the city of Bilbao, Spain.
A 15 MW version called the SG 14-236 DD is currently being developed, with a 236m diameter (774 feet) and a 43,500m2 swept area (468,230 sq.ft.). The first of these units will be installed in 2022, and they will be commercially available in 2024.
There is a reason why manufacturers focus on making wind turbines as large as possible. While you could reach 3 MW of capacity using 30 turbines rated at 100 kW each, a single 3-MW unit is a better option from an economic standpoint.
- The wind is more turbulent close to the ground, due to the presence of natural and man-made obstacles, and more stable at higher altitudes. Taller turbines can reach better wind conditions, making them more productive.
- Wind turbines are also affected by economies of scale: Smaller units can cost you over $5,000 per kW, while large turbines can reach installed costs below $1,500 per kW. The total cost of a megawatt-scale wind turbine is much higher, but its cost per kilowatt is considerably lower.
In other words, a large number of smaller turbines has a higher cost and a lower productivity. By using a smaller number of large turbines, you can drastically reduce project costs while achieving a higher productivity. From a financial standpoint, this means two things: the project payback period is shortened, while the ROI becomes much higher.
Texas is currently the leading wind power state in the US. The nationwide installed capacity surpassed 129,000 MW according to the latest quarterly report from the American Clean Power Association, and 38,000 MW are found in the Lone Star state. The Roscoe Wind Farm is the largest in Texas, having a capacity of 781.5 MW and 627 individual wind turbines. The project was built in four phases, using turbines from different manufacturers:
- Phase 1 (Roscoe): 209x 1-MW Mitsubishi turbines
- Phase 2 (Champion): 55x 2.3-MW Siemens turbines
- Phase 3 (Pyron): 166x 1.5-MW GE turbines
- Phase 4 (Inadale): 197x 1-MW Mitsubishi turbines
With more than $1 billion invested and covering 100,000 acres, this wind farm is capable of powering more than 250,000 Texan households.
How Many Wind Turbines in Texas?
Since wind power is growing so fast in Texas, the exact number of turbines in operation is constantly increasing. However, Texas surpassed 15,000 wind turbines early in 2021, according to an article by Caller Times.
How Much Do Wind Turbines Cost?
The cost of wind power depends on the project scale: Utility-scale turbines are more expensive overall due to their sheer size, but their cost per kilowatt is lower thanks to economies of scale.
- According to the US Department of Energy, the installed cost of large-scale wind turbines currently ranges from $770 to $850 per kilowatt. This means a 3-MW turbine can be expected to have an installed cost of $2.31 – $2.55 million.
- For comparison, the typical cost of wind power was $1,800 per kW back in 2008.
Small windmills are much more affordable, but their cost per kilowatt is higher. For example, you can expect to pay between $40,000 and $80,000 for a 10-kW wind turbine, which is equivalent to $4,000 – $8,000 per kilowatt.
Do Windmills Pay for Themselves?
Like in any investment decision, a wind power project requires a technical and financial analysis before spending any capital. However, with adequate site conditions and a professional design and installation, wind turbines can pay for themselves. The following example is very simplified, but it demonstrates the concept:
- According to the US EIA, the average wholesale price of wind power in Texas is $26 per megawatt-hour (equivalent to 2.6 cents/kWh).
- Assuming a 3-MW wind turbine, the installed cost ranges from $2.31 to $2.55 million.
- At 45% capacity factor, the turbine produces 11,826 MWh per year.
- The output can be estimated by multiplying the turbine capacity in MW, the hours in a year (8,760 h), and the 45% capacity factor.
At $26/MWh, this turbine produces a revenue of $307,476 per year. However, there is also a production tax credit for $15/MWh, or $177,390 per year. The total cash flow is $484,866/year in this simplified example.
However, we must also consider O&M expenses, and $50,000/MW per year is typical for large wind turbines. In this case we’re looking at $150,000/year in O&M expenses, which results in a net cash flow of $334,866/year.
Based on the cost range of $2.31 – $2.55 million, the simple payback period is 6.9 – 7.6 years in this example. Again, this is a very simplified example, and major investment decisions should never be made with quick calculations. A detailed technical and financial analysis is necessary, and it includes a careful measurement of wind conditions at the project site.
Texas Windfarms
Where are the largest wind farms in Texas?
Texas now has more than 15,000 wind turbines, but the following are some of the largest projects in the state:
| Project Name | Capacity (MW) | Location |
| Los Vientos Wind Farm | 912 MW (426 turbines) | Starr and Willacy counties |
| Roscoe Wind Farm | 781.5 MW (627 turbines) | Roscoe |
| Horse Hollow Wind Energy Center | 735.5 MW (421 turbines) | Taylor and Nolan counties |
| Capricorn Ridge Wind Farm | 662.5 MW (407 turbines) | Sterling and Coke counties |
| Sweetwater Wind Farm | 585.3 MW (392 turbines) | Nolan County |
| Buffalo Gap Wind Farm | 523.3 MW (296 turbines) | Taylor and Nolan counties |
Map of Texas Windfarms
Yes, OpenEI has a map of wind farms in the US, and you can zoom into Texas to see the locations of specific projects.
