[NatureNS] wind turbines

From: Patrick Kelly <Patrick.Kelly@Dal.Ca>
To: "<naturens@chebucto.ns.ca>" <naturens@chebucto.ns.ca>
Thread-Topic: [NatureNS] wind turbines
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Date: Thu, 16 Apr 2015 16:58:12 +0000
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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