New Calculations of Global Wind Power Potential

[GliderGuider]

This is a TOD guest post by Carlos de Castro, a professor of Applied Physics in the University of Valladolid in Spain. Carlos is the lead author of an article that was recently accepted by Energy Policy called, "Global wind power potential:athysical and technological limits." This is a link to a summary the author prepared for TOD, since the original article is behind a pay wall.

Global wind power potential: Physical and technological limits

Abstract:

This paper is focused on a new methodology for the global assessment of wind power potential. Most of the previous works on the global assessment of the technological potential of wind power have used bottom-up methodologies (e.g. Archer and Jacobson, 2005, Capps and Zender, 2010, Lu et. al., 2009). Economic, ecological and other assessments have been developed, based on these technological capacities. However, this paper tries to show that the reported regional and global technological potential are flawed because they do not conserve the energetic balance on Earth, violating the first principle of energy conservation (Gans et al., 2010). We propose a top-down approach, such as that in Miller et al., 2010, to evaluate the physical-geographical potential and, for the first time, to evaluate the global technological wind power potential, while acknowledging energy conservation. The results give roughly 1TW for the top limit of the future electrical potential of wind energy. This value is much lower than previous estimates and even lower than economic and realizable potentials published for the mid-century (e.g. DeVries et al., 2007, EEA, 2009, Zerta et al., 2008).

GG: The section on the calculations lists the constraining factors the study considered:

• The energy of the lowest layer of the atmosphere;
• Reachable areas of the Earth (geographical constraint);
• Percentage of the wind that interacts with the blades of the mills;
• Areas with reasonable wind potential;
• Percentage of energy of the wind speeds that are valid to produce electricity;
• Efficiency of the conversion of kinetic energy into electric energy.

Conclusions:

According to the World Wind Energy Association, the electrical wind power produced today is ~0.045 TW and this type of energy is growing at an annual rate of > 25%. If the present growth rate continues, we would reach the 1 TW we estimated in less than 15 years. Therefore, probably in this decade, we will see less growth than we saw in the previous decade.

This limit poses important limitations to the expansion of this energy. Since the present exergy consumption of all energies is ~17 TW, it implies that no more than 6% of today’s primary energy can be obtained from the wind.

Ouch.

[kristopher]

1. I've warned you about garbage from the Oil Drum

Castro claims 1 TW of accessable GLOBAL wind resources given his constraints, right?

Well, either his approach is really, really flawed or 43% of that resource is concentrated offshore within about 50 miles of the US midAtlantic states (330GW) and the shallows off the coast of Brazil (102GW). Total 432GW - and we haven't discussed other areas that are well surveyed such as the Gulf of Mexico, the Pacific Northwest nor the wind corridor extending from Texas into Canada across the midwest.

Both articles contain a complete description of the method used to calculate the resource. If you want more both articles are available at the UD's Center for Carbon-free Power Integration.
http://www.ceoe.udel.edu/windpower/articles.html

MidAtlantic Bight (Cape Cod to Cape Hatteras)
The scientists began by developing a model of the lowest atmospheric layer over the ocean. Known as the “planetary boundary layer,” it extends vertically from the ocean surface to 3,000 meters (up to 9,842 feet) and is where strong, gusty winds occur due to friction between the atmosphere and the sea surface, solar heating and other factors. It provides the “fuel” for offshore wind turbines, which may stand up to 80 meters (262 feet) tall, with blades as long as 55 meters (180 feet).

The scientists examined current wind-turbine technologies to determine the depth of the water and the distance from shore the wind turbines could be located. They also defined “exclusion zones” where wind turbines could not be installed, such as major bird flyways, shipping lanes, chemical disposal sites, military restricted areas, borrow sites where sediments are removed for beach renourishment projects, and “visual space” from major tourist beaches

To estimate the size of the wind power resource, the researchers needed to figure out the maximum number of wind turbines that could be erected and the region's average wind power. The spacing used between the hypothetical wind turbines was about one-half mile apart. At a closer spacing, Kempton said, upwind turbines will “steal” wind energy from downstream ones.

Anemometer readings from the nine NOAA weather buoys in the Middle Atlantic Bight were analyzed. To determine the average wind over the region, the scientists reviewed all the wind-speed data from the past 21 years from one of the buoys. The findings were then extrapolated to the height of the offshore wind turbines currently being manufactured in order to determine the average power output per unit. At the current 80-meter (262-foot) wind turbine height, the extrapolated wind speed of the mid-range buoy is 8.2 meters per second (18.3 miles per hour or 16 knots).

The scientists' estimate of the full-resource, average wind power output of 330 gigawatts ...

http://www.udel.edu/PR/UDaily/2007/feb/wind020107.html



Brazil
Using all of this information, Kempton, Garvine, and Pimenta calculated the potential power production for two different wind turbine models. Kempton said, "The total average electricity use of Brazil is near 100 gigawatts, and the offshore wind resource of this one section of coast, to only 50 meters <164 feet> of water, is 102 gigawatts." That means that if the study area were to become a fully built wind energy project, it could supply enough electricity for the entire country's electricity needs.
http://nasadaacs.eos.nasa.gov/articles/2008/2008_wind.html

The approach used in these studies uses measured wind, measured area, real world distribution of known turbines and actual operational characteristics of the turbines. The locations were chosen not because they have special resources but because they were areas of personal interest to the authors. The results are also completely consistent with Jacobson's earlier work mentioned by Castro.

So unless by chance they stumbled on two of the most productive areas of the world for wind, Castro's work has absolutely no validity.

I am confident it is the latter.

[immoderate]

2. I found something very good there.

I am not familiar with that site but I found this article somewhat interesting, and anti-oil, and post-industrial, unlike typical discourse about jobs.

It ends with:

We might call this way of being, this mode of civilization, the "Ascent of Humanity." It was an age of growth, of domination, of taming the wild and expanding the human realm; of becoming the lords and possessors of nature. That age is ending, and a new era of co-creative partnership with nature is beginning, in which we understand that we are interdependent, not separate. The energy system, and money system, of the future must embody this new relationship.
http://www.theoildrum.com/node/8350#more

--imm

[Gregorian]

3. That is good.

We'll see if it comes to fruition, or if we remain lazy. And by lazy, I mean industrious to a fault.

[kristopher]

4. The site is packed with junk science.

It caters to propaganda exploiting unfounded fears of peak oil apocalypse.

[Nederland]

5. And I've warned you about garbage from Mark Z. Jacobson

Why don't you ever listen? I just don't understand why you don't get that I'm always right and whenever you disagree with me that means you are wrong. How hard is that to understand? If you would just believe everything I say you wouldn't look like an idiot posting nonsense.

I guess some people are just unteachable. Sigh...