The Potential Wind Energy Resource

The Potential Wind Energy Resource

A quick look at an annually-averaged wind map of the world (below) shows the regions of the world that are best suited for the production of wind energy in colors ranging from yellows to red (where the average winds are at least 9.75 m/s or 20 mph). The offshore regions are clearly the best in terms of the energy potential, but not all of these offshore regions are close to where people live. Even for onshore portions of the world, the wind energy potential does not always coincide with where the people are concentrated. This points to the necessity of new transmission lines to deliver this wind energy to major population centers.

The global distribution of onshore and offshore wind resources, showing the annually-averaged wind speed at a height of 100 m. For reference, the blue regions have speeds of 2.5-4 m/s (too low for good wind energy), green regions have velocities in the range of 5-6 m/ (also a bit too low for big turbines), yellow regions have speeds of 6.5 m/s (about 15 mph), which is enough to get most large modern turbines spinning, orange areas range in speed from 7-8.5 m/s, and the red areas range from 8.5 to more than 9.75 m/s, which is plenty of speed to generate wind energy at the full capacity of big turbines.

Credit: Global Wind Atlas(link is external), CC BY 4.0(link is external)

So, just how much energy could be produced by the wind? In 2009, a group of scientists makes some calculations to estimate the potential for the world and the US, using wind data and some assumptions about the size and spacing of the turbines. They assumed 2.5 MW turbines on land, and 3.5 MW turbines offshore, which were big for that time. They assumed that you could only place the turbines in unforested, ice-free, nonmountainous areas away from any towns and that the turbines had to be spaced by several hundred meters so they do not interfere with their neighbors. They further assumed that each turbine generated just 20% of its rated capacity to account for mechanical problems and intermittent winds. What they came up with is summarized in the table below, and it is pretty remarkable. The units here are exajoules (EJ = 1 x 10¹⁸ Joules) of energy over the course of a year. For reference, in 2018, the US total energy consumption (not just electrical energy) was 106 EJ and the global consumption was about 600 EJ. So, with just onshore wind energy, the potential is more than twice what we consume in the US, and more than 4 times the global consumption. But getting there is a matter of installing a lot of wind turbines!

Now let's consider a more practical question — how much wind energy have we managed to produce, and can we somehow project the past trends into the future? The figure below shows the global history of wind energy (solar is plotted too just for comparison), and you can see that it is growing fast.

The history of wind and solar energy production for the world have both grown dramatically over the past 20 years or so. Both curves are following an exponential growth trajectory, increasing by an average of 25% per year.

Click for a text description of the Global Solar and Wind Energy Generation History graph.

The image is a line graph titled "Global Solar and Wind Energy Generation History," depicting the growth in energy generation from solar and wind sources from 1985 to 2020, measured in exajoules (EJ) per year.

• The y-axis represents the energy generated per year in EJ, ranging from 0 to 14 EJ.
• The x-axis represents the years from 1985 to 2020.

Two lines are plotted on the graph:

• Solar energy generation is represented by an orange line. It shows a very gradual increase from 1985, remaining almost flat until around 2005. After 2005, there is a noticeable uptick, with a significant rise starting around 2010, reaching approximately 7 EJ by 2020.
• Wind energy generation is represented by a green line. Similar to solar, wind energy generation starts from a low base in 1985, with minimal growth until around 2000. From 2000 onwards, there is a steep increase, particularly sharp after 2010, reaching around 12 EJ by 2020.

The graph visually demonstrates the exponential growth in both solar and wind energy generation over the years, with wind energy showing a more pronounced increase compared to solar. The data points are marked with small dots along the lines, and a legend in the center of the graph identifies the colors associated with solar (orange) and wind (green).

Credit: David Bice, data from BP Statistical Review of Energy, 2018

Both of these curves are growing exponentially, and the history so far suggests a growth of about 25% per year on average. If we assume that they continue to grow in the further following this exponential growth, we can project where we'll be at any time in the future. Below, we see where we might be in the year 2030, just eleven years from now. What you see is that we end up with vast amount of wind energy by 2030 — if it grows at the same rate it has been growing at, we end up with almost 300 EJ per year, about half of the current global energy consumption, and if it grows at a smaller rate of 20% per year, we still end up being able to supply about 20% of the total global energy demand.

The history of wind energy production for the world projected into the future, increasing by an average of 25% per year and 20% per year.

Click here for a written description of the Global wind energy generation history and projection graph.

The image is a line graph titled "Global Wind Energy Generation History and Projection," which illustrates the historical data and projected growth of global wind energy generation from 1985 to 2030, measured in exajoules (EJ) per year.

• The y-axis represents the energy generated per year in EJ, ranging from 0 to 300 EJ.
• The x-axis represents the years from 1985 to 2030.

The graph features two lines:

1. Historical Data (blue line) - This line shows the actual wind energy generation from 1985 to around 2020. The generation starts from nearly 0 EJ in 1985 and shows a gradual increase over the years, with a noticeable acceleration starting around 2005, reaching approximately 15 EJ by 2020.
2. Projections - There are two projection lines for future growth:
   • 20% per year growth (yellow line) - This projection starts from the point where the historical data ends (around 2020) and shows a steep increase, reaching about 100 EJ by 2030.25% per year growth (orange line) - This projection also starts from the end of the historical data and shows an even steeper increase, reaching around 250 EJ by 2030 

The graph visually represents the exponential growth expected in wind energy generation if the growth rates continue at 20% or 25% per year. The lines are color-coded with labels indicating the growth rates, and the overall trend suggests a significant future increase in wind energy generation.

Credit: David Bice, data from BP Statistical Review of Energy, 2018