I'm guessing you probably don't need me to give you any clues about what this thing is?
Admittedly you don't see too many of them with lurid green blades or any of this
nonsense sticking out the back, but you know, it's a wind turbine isn't it. And its bigger
brothers and sisters are now a fairly regular site across large parts of many of the countries
where you good folks are watching this from. Generally speaking the grown-up versions all
have a very tall mast and three blades, attached to a central nacelle with a heavy duty gearing
system inside to translate the rotational kinetic energy of the blades into useful electrical energy
via a generator. They form part of a sub-category called horizontal axis wind turbines or HAWTs.
But they're not the only way you can get electrical energy from wind. There's a whole
other sub-category called vertical axis wind turbines or VAWTs. These things are extremely
popular among the DIY enthusiast fraternity, many of whom have rigged up rudimentary versions
in their backyards or gardens to provide useful power for their homes.
Now a new company has taken the basic concept of vertical access turbines to create a commercial
model that's designed to work even when there's no prevailing wind. So how do they do that?
Hello and welcome to Just Have a Think. The science of wind turbine dynamics and efficiencies
is pretty much an entire field of technical expertise in its own right.
There have been all sorts of different approaches and designs over the years, all aimed at achieving
the optimal overall performance. Vertical axis turbines or VAWTS tend to fall into one of two
sub - sub categories. Savonius turbines like this one. or Darrieus turbines like these.
And you'll find dozens of very entertaining DIYers on YouTube who've chopped up oil drums
and various other articles to produce their own homemade energy generators.
When it comes to grid scale commercial wind turbines though, there are various
reasons why horizontal axis turbines have generally been favoured over vertical axis.
At those sorts of enormous dimensions early development prototypes of VAWT systems
proved less efficient, and in the days before we had new-fangled composite materials,
VAWTs also proved less reliable as well, with turbine blades tending to shear off
with the constant changing directional forces from the wind. In-depth comparisons between
HAWTs and VAWTs are beyond the scope of this video, but if you want to dive more deeply
into it then I can highly recommend jumping over to my YouTube buddy Rosie Barnes channel,
where you can find two excellent videos explaining the pros and cons of each turbine type.
And you can go straight to the first of those videos by clicking up there somewhere. VAWTs
do have some advantages though. They're obviously much more compact than HAWTs
and they can take energy from the wind regardless of which direction it's coming from.
HAWTs have to have an extra mechanical setup inside the tower called a YAW system,
which turns the turbine into the prevailing wind so that the blades can keep rotating. So vertical
axis turbines have the potential to provide very useful energy in more urban settings where space
is at a premium. Designing a vertical axis wind turbine that doesn't necessarily require the wind
to be blowing though, might seem like a bit of a crazy endeavour, especially for a commercial
enterprise. But that's exactly what a British start-up called Alpha 311 are planning to do
by installing their turbines onto motorway lamp posts, road bridges and roadside buildings,
effectively harvesting the wasted airflow produced by vehicles driving past. The company was founded
in 2018 by business partners Barry Thompson and John Sanderson. Having researched existing studies
of the potential for roadside turbines they realized that the focus was usually
either on placing turbines right at the top of lampposts where they wouldn't get any benefit at
all from oncoming traffic or building entirely new infrastructure in addition to the hardware
that was already there, which of course always proved to be cost prohibitive. So the initial
concept that Alpha 311 pursued was to retrofit existing infrastructure with low level turbines
that would get the benefit of traffic airflow. And they thought that would probably provide enough
power just to run the lamps at the top of the post that the turbines would be attached to. But
when their working prototype was formally assessed by the Institute of Thermofluids here in the UK,
even factoring out any prevailing wind conditions and assuming no traffic at all between 10 pm and
7am, the results still showed far more electricity generation potential than originally anticipated.
The A311 turbine blades start to turn in an airflow speed as low as 1.2 meters per second.
Typical average motorway traffic speeds of 60 miles an hour produce a residual airflow of
5.4 meters per second, which is about 12 miles an hour. At that speed each turbine has a generating
capacity of just over 2.5 kilowatts with a 30% efficiency, or power coefficient to be
more precise. The performance calculations were based on a 5.4 mile section of the M2 motorway
in the southeast of England. Using Department of Transport data for hourly rates of traffic flow
the analysis showed that a single turbine will produce an average daily energy generation of just
under six kilowatt hours. And that particular stretch of road can accommodate 410 turbines,
so the total annual electricity generation along that section worked out at just over 860 megawatt
hours. Which is definitely worth having. The turbines are made from durable recycled
composite materials and have a hollow internal sleeve designed to be very easily retrofitted
around existing posts. Each unit will be up to two metres in height and they'll be extremely light,
weighing between three and a half and eight kilograms, depending on the model.
That doesn't just improve efficiency, it also makes them extremely easy to install.
The blades themselves will be partly shrouded to ensure the optimum energy
harvesting from air flows in both directions and to avoid any cancelling out interference.
Unlike horizontal axis turbines Alpha 311's turbine doesn't need a bulky YAW system
because it can use airflow from any direction, and it has no heavy gearing system either,
just a neat little static magnetic stator housed in the base of the unit with a stainless steel
rotor inside it which is attached directly to the base of the turbine. As the rotor turns
within the stator it generates an electrical current that gets sent to a charge controller
via the cabling that already exists to supply the lamp post with power. The charge controller then
sends that current through an inverter and back into the local grid with far smaller transmission
losses than other remotely located power sources. The space allocated for the magnetic stator also
houses a centre array for data collection from sensors that can be mounted onto the lamp post,
which means that Alpha's system can also monitor air quality weather conditions and traffic
statistics, all of which can be sent out via an internet of things, or IOT, gateway to monitoring
stations in real time via a 4G or 5G wireless connection. Now you super smart technically
minded types out there might be thinking all that apparently free energy is coming from vehicles
that all require energy to make them move in the first place and in the vast majority of cases at
least today anyway that energy will have come from fossil fuels in the form of diesel or petroleum.
But those vehicles are all punching a hole in the air and causing airflow around them
regardless of whether there's a turbine or a building or anything else at the side of the road,
and that airflow is essentially just wasted energy. So scooping it up into turbine blades
that can drive a generator to produce electricity is a smart use of already existing resources.
that will be sited on the round towers surrounding the 02 centre in East London. After that Alpha 311
will be supplying 54 turbines to a New York development called Green Asphalt.
The medium-term goal is to get these turbines installed on motorways and trunk roads all
over the United Kingdom and the wider world, but Alpha 311 have longer term aspirations beyond that
too. Although the quoted performance figures are based on traffic airflow, the turbines
obviously do work just as well in prevailing wind conditions, and one obvious secondary
application for compact lightweight turbines like these is on telecommunications masts.
There are hundreds of thousands of those things across the globe, enabling our mobile phones
to work wherever we are. A typical 5G mast uses about seven kilowatt hours of energy every day.
One of these turbines installed on each of those masts will provide very nearly all the power they
need, removing a significant load from our national grids. And as long as the relevant
regulations are adhered to there's no reason why smaller versions of these turbines couldn't
be installed on domestic homes, possibly even in conjunction with solar power and battery storage
to provide a much wider time window of power generation for the householder. That
sort of system would pull a lot of people, even here in the UK, out of fuel poverty.
And in developing nations it would be yet another option for people in remote off-grid areas
to consider alongside solar and micro hydropower that we looked at in a recent video.
It is very early days with the first production run only just going through now,
and I know that one of the criticisms these start-up companies get is that they're unproven
and might not achieve the numbers they're predicting. And I get that. It's a perfectly
reasonable challenge. But companies like Alpha 311, and so many others all over the world,
are all working towards the same basic end goal, which is to develop working alternatives
to the existing dominance of fossil fuels on our electrical grids. Alpha 311 installations will
never replace onshore or offshore wind turbines and they're not designed to, but they can provide
a very valuable complementary power source that'll improve the diversity of renewable energy inputs
onto those grids, and for that reason I for one think they should be applauded.
No doubt you've got your own views on this one though. If you have,
or if you work in related industries and you've got insight that you can share,
then jump down to the comment section below and leave your thoughts there.
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