Last month we discussed a few basic aspects of wind as a source of clean energy. We showed what wind was, how it forms and where it goes. Then after going on a tangent about the history of turbines, we showed where on the Earth we could recover the highest amount of wind energy and how this potential changes with altitude. Today’s post offer the pros and cons of wind energy while touching upon several topics discussed in the previous post before diving into the optimal where and when.
Getting into the “What”
With an established worldwide potential of more than 400 TW (20 times more than what the entire human population needs) and a clean, renewable source wind is definitely attractive to the current and future generations. In terms of harvesting it, over 99% percent of wind farms in the USA are located in rural areas with 71% of them in low-income counties. Indeed, the more land is available (and the fewer buildings), the higher the possibility and interest to transform this kinetic energy into mechanical work and then most likely electricity.
Where one would see sporadic turbines on the side of the highway, these stand-alone equipment have begun to turn into actual modules (farms) that can work as an overall unit instead of individual ones. This strategy of creating a network of turbines follows the philosophy of “the Whole is Greater than the Sum of its Parts”. What this translates into is that by having 20 (arbitrary number) wind turbines working together to determine the best orientation, pitch, etc. of their blades in such a way that it least negatively impacts the downstream units we can produce more energy than if each of them were live-optimized individually (some interesting A.I. work is going into this). This means that the overall system is more efficient at converting energy and therefore it is more cost effective to provide bulk power to the electrical grid. This is similar to the concept in the post on solar energy comparing PV panels and CSP. Read the full post here.
In terms of power production per wind turbine, the utility-scale ones range from about 100 kW to several MW for the land-based units (Offshore wind turbines are typically larger and produce more power – getting ahead of myself here but check out the figure below for wind potential in Western Europe that clearly showcases coast vs. non-coast data). On the low-power end of the spectrum, we find some below 100 kW for some non-utility applications like powering homes, telecommunications dishes, water pumping, etc. Solar power (PV) is generally regarded as the first choice for homeowners looking to become energy producers themselves, but wind turbines make an excellent alternative in some situations. It would take a wind turbine of about 10 kilowatts and $40,000 to $70,000 to become a net electricity producer. Investments like this typically break even after 10 to 20 years.
Onto the “Where”
One of the elements of wind formation we covered in the last post here was a different in pressure (and therefore temperature). This simplification works rather well at the macro-scale, but as we zoom in closer to the surface we can see that wind flow speeds and patterns vary quite significantly based on more than just the general location of Earth. On top of the altitude we already discussed, factors like vegetation, presence of high-rise buildings or bodies of water come into play.