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> Daily Paintings - http://karstaddailypaintings.blogs
Nick's examples of the complexities of renewable and non-renewable energy decisions is a welcome reminder, but omits several renewable sources like energy extraction from wave action, tidal fluctuation, geothermal sources, and 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 like those here without going into what is technically feasible in terms of practical energy extraction from various sources, then modulating this by social/political constraints. Otherwise 'that's mostly hot air', to quote MacKay (see next) -- you need hard numbers not verbiage.
A remarkable book that I came across that is both very readable and with lots 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 renewable and non-renewable energy sources is by David J. C. MacKay "Sustainable Energy - without the hot air", 383 pages. Download the PDF file, for free (!), from
www.withouthotair.com
the book file is an acronym, called sewtha.pdf, about 13.9MB. My copy is 2009 but he may update the file periodically, it says somewhere. He's a Cambridge UK physicist and writes engagingly well in a quite folksy manner. The numbers in the examples are taken mostly from UK, but would probably apply largely to any developed country after rescaling.
Briefly, among comments relevant to this topic of wind power, he says 30,000 birds are killed per year in Denmark (which gets 9% of its electricity from its many wind turbines), versus 1,000,000
killed by encounters with traffic (ratio 3 : 100). He couldn't find data for Denmark, but an estimated 50,000,000 birds are killed by cats in UK (larger land area and population); the number for collision with UK building windows 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 variable. You'd think that this would average out if you had a lot of well distributed 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 [naturens-owner@chebucto.ns.ca] on behalf of John Kearney [john.kearney@ns.sympatico.ca]
Sent: Wednesday, April 15, 2015 9:35 PM
To: naturens@chebucto.ns.ca
Subject: RE: [NatureNS] wind turbines
Hi All,
As someone who has conducted environmental assessments at about a dozen wind energy facilities in Nova Scotia I would like to make a contribution to this thread. Certainly wind energy will play a crucial role in providing renewable energy to Nova Scotia, and so far the evidence suggests that bird mortalities at wind energy facilities are relatively low compared to other sources of human-generated mortality. Nonetheless, I think birders and bird conservationists need to be more vigilant in evaluating the effects on birds. First, the mortality studies that have been conducted are limited in their ability to measure mortalities. Most fatalities probably occur at night and 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 the 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 concern is the lack of regional, peer-reviewed, scientific studies on the effects 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 habitats, and breeding areas in their attempt to avoid a turbine or turbine array. So far, studies have been piece-meal, the data is often confidential, and assessments are made on a case-by-case basis without reference to broader issues, cumulative impacts, and habitat fragmentation. Regional studies, including ground, acoustic, and radar survey techniques, are especially important in evaluating the impact of wind energy facilities constructed in coastal 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 turbines on coastal headlands under most conditions, we do not have the knowledge to predict under what conditions these catastrophic events might occur, and without on-going monitoring, we might not ever know that they occurred. I would suggest that the environmental permits for wind energy facilities require that all data collected be made public and that industry, government, and conservation groups support regional studies that can lead to a more informed and integrated approach to reducing the risk of wind energy production on birds.
John
From: 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
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 evils and, given available options, I have felt for decades that wind was way better than alternatives and should be quickly developed to the maximum possible.
Nuclear however may make a comeback eventually. The great disadvantage of conventional Nuclear Power has been the production of radioactive waste (unless you happen to want the waste for potential production of dirty atomic weapons). But an alternative based on Thorium, in addition to modular design advantages, leads to 95% less nuclear waste.
But that is for the distant future and, meanwhile, ways to cut carbon emissions so climates and ecosystems do not enter an interactive death spiral should be top on the agenda. Without meaningful cuts in carbon emissions there will be no distant future for many species in much of the world.
Yt, Dave Webster