by nb41
Fri Feb 19th, 2010 at 11:29:05 AM EST
There is a newly released blurb on the American Wind Energy Association (AWEA) website (see http://www.awea.org/newsroom/releases/02-18-10_US_Wind_Resource_Larger.html) that is definitely worth a look, a mirror of one from the US Dept of Energy:
http://www.windpoweringamerica.gov/filter_detail.asp?itemid=2542
This is about a serious update of the wind energy potential that was last estimated in the 1979-1981 era (see http://rredc.nrel.gov/wind/pubs/atlas/), and which was woefully out of date. This new one used wind speeds present at 80 meter heights (most commercial scale units installed in the US are have been on 80 meter tall towers for several years). This is still a pretty conservative estimate, and the details are a bit sketchy.
But, the estimate is that 37 million gigawatt-hrs/yr (an average of 4220 gigawatts (GW) of continuously produced power) could be made with wind turbines putting out an average of 30% of their rated gross capacity (i.e. no shutdowns for maintenance and inspections). Since the average net output (the electricity put on the grid and which turbine owners get paid for) is about 94% of the gross output, that's still close to 4 Terawatts (TW) of average output. It would take about 10.5 million GW of wind turbine capacity, or about 4.2 million x 2.5 MW wind turbines to supply this rather large quantity of power/energy.
And there is only one problem - the US only used an average of 425 GW in 2009. So, using the net output basis, we have 9.3 times too much wind capacity. And even if we replace all the natural gas heating with renewable electricity, that would only boost the demand to around 750 GW. We have too darn much wind capacity - what are we to do with all this useless potential, eh?
Maybe we could get Goldman Sachs to write up some CDS's on all this unusable potential....just kidding.
There is another small point about this study - just what constitutes a wind speed needed to get a 30% gross energy output? For that, we will have to wait for the full report to come out, which will hopefully be in the near future. As expected, the midwest really shines (for example, Texas could more than power up the country, and Nebraska could almost do it). Of course, there is also the matter of getting the electricity from where it is made to where it will be used by actual human beings and in the factories, offices and homes they use. Or maybe it's time to start transplanting people to where the energy is (but then there is the water problem....). So maybe it's easier to keep most people where they are.
This study does not touch upon offshore (Great Lakes, Atlantic and Gulf, or the deepwater potential of the very windy west coast (it's shallow on the Atlantic side, not on the Pacific side)). And it excludes a lot of potential in more populated areas, or in the southeast, because of the requirement in this study for the 30% gross output.
Here is why that is important. Different wind turbines tend to be targeted to different wind regimes. A turbine designed for fast winds (like Altamont Pass wind canyons) will not work so well in more moderate wind regimes. And one designed for more moderate winds like those in NY State (onshore anyway) will get torn to shreds in the windy zones - the blades are too big for the generator, and the unit would self-stop for a considerable part of the year. Anyway, here are some examples of wind speeds at hub heights that will give a 30% gross output at close to standard conditions (15 C air temperature, sea level).
Wind Turbine ........................... Wind Speed needed for 30% Gross Output
Vestas V-100 x 1.8 MW ........... 5.8 m/s
Vestas V-90 x 1.8 MW ............. 6.1 m/s
Vestas V82 x 1.65 MW ............. 6.3 m/s
Vestas V-90 x 3 MW ................. 8 m/s
GE 1.5s 1.5 MW x 70 m rotor .... 6.8 m/s
GE 1.5sl 1.5 MW x 77 m rotor ... 6.5 m/s
The Vestas numbers (V-90) correspond to the rotor diameter. And since the power in the wind is proportional to the cube of the wind speed.... well, the V-100 x 1.8 MW unit tapping 5.8 m/s wind is getting a 30% gross out from winds with about 71% of the power of those needed by the GE 1.5sl (now the most widely used wind turbine in the US). Those same 5.8 m/s winds have less than 39% of the power that are needed for the Vestas V90 x 3 MW unit (they do best in 9 m/s average wind speed zones...).
So, by using turbines designed for more mellow wind resource areas, a lot more land gets opened up. Another trick is to use a taller tower - as is often done in Europe. Winds at 100 meters above the ground could easily be more than 5 to 10% faster. Tower heights in Europe are often 113 meters (the tallest is 160 meters). And really big turbines, like the Enercon E-126 x 7.5 MW unit need tall towers just to keep the blades in windy zones (the E-126 would reach up to 204 meters above the ground).
Anyway, this is great timing. President Obama has just decided to pursue the "nuclear option" - no, not to get rid of the filibuster in the Senate and pass some modest Health Care proposal, but to pay back a big campaign contributor - Exelon (formerly Illionis's biggest utility, Commonwealth Edison, now sort of spun off as a nationwide electricity generator - see http://en.wikipedia.org/wiki/Exelon). Those new nukes proposed for Georgia would, if they ever do get built, deliver electricity at more than 20 c/kw-hr - and with no mandate for high level trash disposal or catastrophic insurance (that one is probably worth $500 million/yr per reactor, assuming it was even possible). Oh well, now that the Yucky Mountain trash disposal site is no longer an option, I hope the folks in Georgia understand that the disposal site for that trash is going to be located...at the site where those reactors get installed (in adjacent "swimming pools). Won't THAT do wonders for property values...
Maybe the President can make a better PR announcement for this stinker of a project in Georgia on April 26... assuming he has a shred of courage. Hint, April 26 is one of those anniversaries that a lot of people would really like to forget about... especially the nuke crowd). See http://en.wikipedia.org/wiki/Chernobyl_disaster.
Also cross-posted on http://www.dkgreenroots.com
Nb41
