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c3VlcywgY3VtdWxhdGl2ZSBpbXBhY3RzLCBhbmQgaGFiaXRhdCBmcmFnbW --_000_C11F7B0CB7BC4700AD57A77C312F258Cdalca_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Here is another great book. It is a bit dated but the laws of physics haven= 't changed. The worked examples are done so that anyone can follow them. My= son had this as a text for one of this engineering courses. http://www.amazon.com/Energy-Problems-Technical-Society-Kraushaar/dp/047157= 3108 It may be hard to find, but worth it if you can! Pat On Apr 16, 2015, at 2:35 AM, Stephen Shaw wrote: Nick's examples of the complexities of renewable and non-renewable energy d= ecisions is a welcome reminder, but omits several renewable sources like en= ergy extraction from wave action, tidal fluctuation, geothermal sources, an= d of course photovoltaic and solar concentrator sources. I don't think you= can do justice to all this and get much useful out of verbal exchanges lik= e those here without going into what is technically feasible in terms of pr= actical energy extraction from various sources, then modulating this by soc= ial/political constraints. Otherwise 'that's mostly hot air', to quote Mac= Kay (see next) -- you need hard numbers not verbiage. A remarkable book that I came across that is both very readable and with lo= ts of pictures and graphs, and is full of feasibility calculations made in = an accessible way, and that I'd highly recommend if you are interested in r= enewable and non-renewable energy sources is by David J. C. MacKay "Sustain= able Energy - without the hot air", 383 pages. Download the PDF file, for= free (!), from www.withouthotair.com<http://www.withouthotair.com> the book file is an acronym, called sewtha.pdf, about 13.9MB. My copy is 2= 009 but he may update the file periodically, it says somewhere. He's a Cam= bridge UK physicist and writes engagingly well in a quite folksy manner. T= he numbers in the examples are taken mostly from UK, but would probably app= ly largely to any developed country after rescaling. Briefly, among comments relevant to this topic of wind power, he says 30,00= 0 birds are killed per year in Denmark (which gets 9% of its electricity fr= om its many wind turbines), versus 1,000,000 killed by encounters with traffic (ratio 3 : 100). He couldn't find data f= or Denmark, but an estimated 50,000,000 birds are killed by cats in UK (lar= ger land area and population); the number for collision with UK building wi= ndows is believed to be similar to the toll taken by cats. Wind power is 'sustainable' but is not useful by itself because it is so va= riable. You'd think that this would average out if you had a lot of well d= istributed wind turbines, but apparently not so. MacKay shows daily figures= for a recent year, averaged for all of Ireland: these fluctuate wildly by = more than a factor of 10, with several days in a row with no wind power at = all. Lots of other stuff -- great book, very informative, and it's free! Steve (Hfx) ________________________________________ From: naturens-owner@chebucto.ns.ca<mailto:naturens-owner@chebucto.ns.ca> [= naturens-owner@chebucto.ns.ca] on behalf of John Kearney [john.kearney@ns.s= ympatico.ca] Sent: Wednesday, April 15, 2015 9:35 PM To: naturens@chebucto.ns.ca<mailto:naturens@chebucto.ns.ca> Subject: RE: [NatureNS] wind turbines Hi All, As someone who has conducted environmental assessments at about a dozen win= d energy facilities in Nova Scotia I would like to make a contribution to t= his thread. Certainly wind energy will play a crucial role in providing ren= ewable energy to Nova Scotia, and so far the evidence suggests that bird mo= rtalities at wind energy facilities are relatively low compared to other so= urces of human-generated mortality. Nonetheless, I think birders and bird c= onservationists need to be more vigilant in evaluating the effects on birds= . First, the mortality studies that have been conducted are limited in thei= r ability to measure mortalities. Most fatalities probably occur at night a= nd two things can happen to mask the extent of mortality. The first is that= scavengers can clean up carcasses before the carcass searchers arrive in t= he morning. Second, carcass searchers are usually limited to searching the = gravel pads at the base of the turbines. Depending on the size of the bird,= the turbine blades can throw the birds well beyond the pads into vegetated= or rocky areas where they can be extremely difficult to detect. Another co= ncern is the lack of regional, peer-reviewed, scientific studies on the eff= ects of wind energy facilities on bird and bird habitats. Not only is there= a danger of collision but birds can be diverted from flyways, feeding habi= tats, and breeding areas in their attempt to avoid a turbine or turbine arr= ay. So far, studies have been piece-meal, the data is often confidential, a= nd assessments are made on a case-by-case basis without reference to broade= r issues, cumulative impacts, and habitat fragmentation. Regional studies, = including ground, acoustic, and radar survey techniques, are especially imp= ortant in evaluating the impact of wind energy facilities constructed in co= astal locals, and especially headlands. These are the areas where migrants = concentrate, often in very large numbers and under poor weather conditions = (such as fog and high winds), and when birds may be already stressed from a= long flight or from being blown out to sea. Such conditions could lead to = infrequent but catastrophic events. An example, is the case of the natural = gas plant St. John, NB., a couple of years ago when hundreds of birds were = killed in circling a gas flare. So while birds may be able to avoid the tu= rbines on coastal headlands under most conditions, we do not have the knowl= edge to predict under what conditions these catastrophic events might occur= , and without on-going monitoring, we might not ever know that they occurre= d. I would suggest that the environmental permits for wind energy facilitie= s require that all data collected be made public and that industry, governm= ent, and conservation groups support regional studies that can lead to a mo= re informed and integrated approach to reducing the risk of wind energy pro= duction on birds. John From: naturens-owner@chebucto.ns.ca<mailto:naturens-owner@chebucto.ns.ca> [= mailto:naturens-owner@chebucto.ns.ca] On Behalf Of David & Alison Webster Sent: April-15-15 19:25 To: naturens@chebucto.ns.ca<mailto:naturens@chebucto.ns.ca> Subject: Re: [NatureNS] wind turbines Hi Nick & All, Apr 15, 2015 I agree almost entirely with your analysis Nick. In the real world, most choices involve selecting the lesser of two