Are wind turbines indiscriminate
bird killers as many new stories and politicians would have us
believe? Or are they the renewable energy technology
that's ultimately going to save birds? Today I'm going to unravel the
facts from the fiction to find out whether wind turbines really
are a significant danger to birds and discover which
technologies are available to allow them to coexist. I'm Rosie Barnes. Welcome to
Engineering with Rosie. I'm a mechanical engineer
complete with PhD, I've worked with renewable energy
technologies for the past two decades, a lot of that designing
wind turbines, also I'm a certified bird-nerd. Australia has THE best birds in
the world and I often take my binoculars with me in daily life
so I can identify and check off new sightings in my bird app. I've taken hours of video and
1000s of pictures of birds, some of which you're going to be
seeing on screen in this video today. I even named my clean energy
technology consulting company after my favorite bird, the tiny
pardalote. With my dual perspective as an
engineer and bird-nerd, I strive to approach the issue of birds
and wind turbines with the utmost impartiality. So let's cut to the chase. Why
wind turbines killing birds? After all, a wind turbine is a
huge piece of machinery and birds have notoriously good
eyesight. Why aren't they simply avoiding them altogether? Well, one reason is that many
birds, particularly birds of prey, they're looking down at
the ground in search of their next meal. With their eyes
focused below, they fail to notice wind turbine blades
rushing down to them from above. Then there's the speed of wind
turbine blades. Yes, they look kind of peaceful and serene when
they're viewed from afar. But even though the rotational speed
of wind turbines is low, the blade tips actually usually
traveling over 300 kilometers per hour, and even the fastest
and most agile birds are going to have trouble avoiding that if
they get too close. he other reason that we've seen
large numbers of bird fatalities around wind farms is location
and siting of those farms. For example, California's
infamous Altamont Pass wind farm was constructed right in the
middle of a migratory bird route. The area is host to hundreds of
1000s of migrating birds passing through each year, and it's a
permanent home to 1000s more birds of prey that rely on
migratory birds to sustain them. With such large numbers of birds
and wind turbines all concentrated together,
fatalities are probably inevitable. Now, it's not just birds that
are at risk. Wind farms also pose an equally serious threat
to bats. But bats aren't generally held in as high esteem
as birds are, maybe their PR isn't as good. So you're less likely to hear in
the media about the plight of wind farms versus bats. I personally think that bats are
amazing, they're mammals like you and me, but they've managed
to evolve themselves to the point where they have flight and
sonar capabilities without needing to step inside a fighter
jet or submarine like we do. And I'm told bats are just as
crucial to ecosystems as birds are, being an essential
pollinators, seed disperses and pest controllers. So just how many birds and bats
are killed by wind turbines? There are some good US studies
on this topic, which each shows estimates of a few 100,000 bird
deaths in the US attributable to wind farms They were using 2012
data and since the amount of wind energy produced in the US
has just about doubled since then, we can extrapolate for
that and estimate that around about a million birds are killed
in the US from wind farms each year. The number of bats killed by
wind farms is similar. Although those numbers are a little bit
less reliable. Of course, the combined number
of potentially upwards of 2 million birds and bats killed by
wind turbines in the US each year is a vast one. And remember
that that's just the US, if you think of the globe as a whole
then it's going to be many times that. I mentioned I'm a bird
and bat lover and as such, I think that millions of birds and
bat fatalities due to wind turbines absolutely sucks. However, this is nothing
compared to the number of birds killed by other human causes
each year. Powerlines, communication towers, cars and
buildings each cause 10 to 1000 times more bird deaths than wind
turbines do. But even THIS is a fraction of
the number of deaths caused each year by Felis Catus. Better known to you and me as
the domestic cat. That's right, that little
purring ball of fur on your sofa is responsible for around two
and a half billion bird deaths each and every year just in the
United States. And there's another killer that
I haven't yet mentioned. And it's a threat that's poised to
kill not just millions of birds and bats each year, but
potentially to wipe out entire species. Truth is that the biggest threat
to birds, bats and indeed all wildlife is climate change. Unless something can be done to
stop environmental change to the habitats and ecosystems in which
wildlife lives, all animals will face massive reductions in
populations or even extinction. Of course, one of the primary
methods we're going to use to bring climate change back under
control is through switching to renewable energy sources,
particularly wind power Every credible net-zero energy
scenario includes a huge amount of wind energy in the equation,
it'll be vastly more difficult, more expensive and MUCH slower
to transition to renewable energy sources without wind For example, using only solar
would mean we would need huge amounts of energy storage for
use at night plus dramatic developments in long duration
energy storage to account for less solar energy throughout the
winter months. So if wind turbines are
essential to combating climate change and thus play a BIG role
in protecting wildlife in general, what is the engineering
community doing to ensure that wind turbines are safe for avian
wildlife? One of the biggest reductions in
wind turbine bird death has been the design of wind turbines
themselves. I mentioned earlier the Altamont
Pass wind farm in California, which is often cited by wind
turbine critics for the high number of bird deaths it caused. Well, the turbines at the
Altamont Pass were designed and constructed back in the 1980s
and were therefore much smaller than modern wind turbines. The blades on small turbines are
situated much lower to the ground and they rotate faster,
so they pose a greater risk to birds and bats during takeoff
and landing. Not only are engineers now
designing larger wind turbines, the designs are also sleeker. Older tower designs were often a
lot of structure similar to electricity towers and birds
found that ideal for perching on. Unsurprisingly roosting
directly underneath spinning blades led to many bird deaths. Today, wind turbines are
designed with monopole towers that offer a few perching places
for birds or bats As the original 1980s and 1990s
wind turbines at Altamont Pass, and many other wind farms around
the world are getting replaced with more modern wind turbines,
they're becoming safer for birds. When bird deaths from old and
new turbines operated concurrently at Altamont Pass
are compared, it was found that the modern wind turbines have
66% lower bird deaths per unit of energy generated Another method engineers have
looked into in order to make wind turbines safer for birds is
to paint one of the turbine blades black. When all three turbine blades
are left while they kind of blend together as they rotate
and they're harder to see, but the addition of black either a
single blade or stripes on the blade creates a visible pattern
as they spin making it easier for birds to see them. A small study in Norway painted
black blades on 4 wind turbines and over a period of three years
they found the number of bird collisions to be reduced by 70%
compared to control turbines. A slightly larger trial was
seven turbines owned by RWE is ongoing in the Netherlands and
it's due to be completed at the end of 2024. This solution sounds SO simple,
but in reality it does create some complications with both
manufacturing and function. Wind turbine blades usually get
their color from a gel coat that's put the mold before the
fiberglass and other materials are laid in there It would be hard to make a third
of the blades with a black gel coat because blade straight out
of the factory, they don't all weigh the same, they need to be
matched into sets of three blades of similar weight so that
the turbine rotors are balanced. Adding in the need to match sets
by color as well as matching them by weight would make a huge
pain for the factory. Also, a black blade will heat up
in the sun and become more flexible and therefore bend more
against the wind. So if it's just one single black blade on
the rotor that could unbalance the turbine, not to mention
because it bends more there's a possibility it could hit the
tower or even break from fatigue loading if the bend was severe. So that might be the reason that
20 years after the original study into this idea was
published, we've only seen a total of 11 turbine blades
painted. It only sounds simple. It's not
really as easy as just getting out a can of spray paint. Closer to home, or my home
anyway, is the introduction of cameras and radar technologies
to wind farms. The Capitol Hill wind farm in
Tasmania uses optical devices and AI software to detect
vulnerable wedge tailed eagles and white bellied sea eagles When the system identifies
either of these protected species, it initiates a brief
shutdown on the turbine stopping their blades turning until the
bird or birds have left the area Capitol Hill wind farm went into
operation in 2018 and the final report on the effectiveness of
the IdentiFlight Avian Detection System was published in 2022. It showed a significant drop in
actual eagle fatalities compared to predictions. Also in Tasmania, the Musselroe
wind farm uses a new avian specific radar technology to
detect endangered birds and enable the turbines operation to
be adjusted to prevent collisions The technology provides 3D
coverage across a visible field from the horizon to one
kilometer above ground. Once an endangered species is
detected, the radar system can initiate turbine shutdown During its first six years of
operation with the radar system Musselroe wind farm experienced
just a single white bellied sea eagle death and 11 wedge tailed
eagle deaths due to turbine collisions. As I said at the beginning,
birds aren't the only flying wildlife affected by wind
turbines, bats are equally at risk To prevent bat death, sonic
deterrents have been installed at wind farms for over 20 years
now Speaker systems installed on top
of wind turbines can emit a high frequency ultrasound that
discourages bats from approaching the area without
causing them any harm Being beyond the hearing limit
of humans or other wildlife species, the sound is otherwise
unobtrusive. Figures show reductions in bat
deaths as high as 78% thanks to sonic deterrents. Sometimes, the simple solutions
are the most effective and the Dutch government are currently
trialing one such simple program. Wind farms situated across known
migratory routes will slow or halt the rotation of their
blades during migratory seasons, thus reducing the chances of
birds being harmed. A model developed by the
University of Amsterdam predicts up to two days in advance when
birds will be migrating across the North Sea in search of
warmer climates. Using this advanced warning,,
the Dutch government will require the energy companies to
reduce the rotation of turbine blades or stop them completely
for 12 to 48 hours, allowing birds to safely pass through
specific areas. As I said, this program is brand
new and currently undergoing trials but it's believed it will
significantly reduce the approximately 50,000 bird deaths
caused by Dutch offshore wind farms each year. And it's not just changes to
wind turbines that can prevent bird and bat collisions. Studies into land management
suggest that lightly tilling the soil around wind farms makes the
area a less attractive habitat for birds of prey to settle in Superficial tilling prevents
rodents and other small animals from making the area their home
and with nothing to feed on, birds of prey will look
elsewhere. A study in the Journal of
Environmental Management showed that soil tilling around wind
farms led to a 75 to 100% decline in collisions between
kestrels and wind turbine blades over a two year period. The ongoing study of bird
behaviors has become a determining factor in the
planning and construction of wind farms. From an engineering
standpoint, the location dictates how much energy the
wind farm is going to produce. But the location also plays a
huge role in the coexistence between the wind turbines and
the surrounding wildlife. It used to be much more the case
that wind farms were constructed based nearly entirely on where
the winds were strongest and most consistent, but now the
environmental approvals at all wind farms are subject to during
their planning and development phase include ensuring that wind
turbines cause minimal disruption to birds and bats. The Altamont Pass wind farm in
California that I mentioned a couple of times is a good
example of how these legislative changes based on scientific
studies findings are shaping just where energy companies are
allowed to construct new wind farms. And as our understanding of
exactly how wind farms affect birds, bats and other forms of
wildlife improve, so new legislation will be enacted,
making wind farms even better for the ecosystem and wildlife
as a whole. So as we've seen, while wind
farms aren't perfect, they are nowhere near the worst threat to
the safety of birds and bats. Thanks to the work of scientists
and engineers across the globe, there are now a range of
solutions being implemented to ensure the safety of wildlife
and especially of endangered species. I think it's interesting that
the amount of attention paid to wind turbines and birds is so
disproportionate to the number of deaths that they cause You probably never thought to
worry about how many birds are killed by buildings or
powerlines each year. And I would suggest if you are worried
about birds, then I would think about keeping your pet cat
inside as a much more impactful thing to do than opposing a
local wind farm. After all, we need the wind
farms to mitigate climate change which is overall the biggest
threat to birds. If you want to help me to
produce videos like this, then consider joining the Engineering
with Rosie Patreon team at this link. I can assure you that
doing so won't hurt any wildlife and it's a great help to me in
growing this channel and sharing knowledge about renewable energy
engineering and other clean energy technologies. Thanks for watching and I'll see
you in the next video!
