JJJN <[EMAIL PROTECTED]> wrote: > I was really bored out of town this week so I watched TV. The most > interesting thing I could find was a Rep from Maryland was speaking > about Alternative fuels on C-Span. He made an interesting argument for > alternatives. I was sorely disappointed that he did not mention or even > list Biodiesel as an alternative fuel. There were 25 Million gallons of > Biodiesel in US commercial production not counting private in 2004. I > am currently reading Greg Pahls book "_BIODIESEL - growing a new energy > economy"_ which contains some very forward looking information. The > bottom line here is a question - Why is this source so ignored when it > produces over 3 gallons for every one expended?
Could be that the major oil companies, who "own" the current U.S. administration, don't control the production of biodiesel, and therefore wish to suppress it. Oops, I think my cynicism is showing. > > What do you folks see as the top 10 replacement fuels and in what > order. Currently hydrogen is right next to coal on my list as we must > burn so much coal to use this "clean fuel" Here's my "top ten" - it's energy sources, more or less, rather than "fuels". 1) Negawatts (efficiency, conservation). 2) Low-tech solar. 3) Low-tech geothermal (berming, ground/water-coupled heat pumps). 4) Wind. 5) Biodiesel, SVO. 6) Ethanol. 7) Hydro. 8) Photovoltaics. 9) Wood. 10) Methane. > > Ok one last question about wind farms. I told someone that wind farms > have the _potential_ of changing the weather if there is enough energy > extracted. I was laughed at and got that "look" _Now I did say > potentia_l. The laws of thermodynamics say so. So can any one share > some more insight to this potential possibility?? Without question, wind turbines extract mechanical energy from the wind. In effect, they slow the wind down to some extent. The real question is whether or not they have potential for changing the weather. Personally, I would say not in any realistic scenario. Global warming implies that average windspeeds will increase. I submit that wind turbines of current designs will not extract enough energy to offset that increase. The key to the argument, IMO, is that wind turbines cover such an insignificant portion of the wind cross section as to be meaningless. Winds move to heights of over 15,000 metres above the planet's entire surface. Turbines rise to heights of about 150 metres (top of blade tip for large turbines), or about 1%. They interrupt the slowest of the winds - those closest to the surface which are slowed and disrupted by surface features. So the 1% overstates the amount of energy they can intercept dramatically. Then, turbines will only ever cover some tiny percentage of the planet's surface - let's guess 1/10,000 of 1%. Then, the turbines only extract a small percentage of the energy in the winds they do intercept - say 20% maximum for a perfect turbine. So, putting that together, my "back of the envelope" guess is the impact on wind energy of a massive implementation of wind turbines is in the order of 1/5,000,000,000th of the available energy. I suspect it will be hard to measure the impact of that extraction on changing the weather or climate. However, global warming is already having measurable impacts on climate. http://www.livescience.com/environment/041109_wind_mills.html I think David Keith's estimate of wind farms covering 10% of the planet's land surface is beyond extreme. As for Somnath Baidya Roy's research, his simulation indicates that wind turbines that extract energy from the wind will result in *increased* local wind speed. Of course, his model doesn't allow for planting of trees as windbreaks or any other remedial action, assuming his theoretical model is correct. IMHO, the impact is strictly theoretical, and not going to be observed in practical terms. -- Darryl McMahon http://www.econogics.com/ It's your planet. If you won't look after it, who will? _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
