I do a lot of talking on this channel about the amazing breakthroughs in laboratories and test
centres all over the world that are aimed towards decarbonizing human activity and energy use.
The vast majority of them are focused on providing renewable power and energy storage to our
electricity grids but there are still almost a billion people in the world who don't have
access to a national or regional grid and although the mass migration into cities especially in the
developing nations has brought that number down significantly over the past decade there are still
an awful lot of remote locations that will most likely never receive the infrastructure for a
grid connection. So for the hundreds of millions of folks living in those areas the options are
horrible dangerous kerosene lamps to provide light during the evenings, and noisy generators running
on diesel which is an increasingly expensive fuel that pollutes the air and dumps huge amounts of
carbon dioxide into the atmosphere. In recent years solar PV panels on individual homes have
played a significant role in improving the lives of many of those people but solar does have that
inherent and inconvenient intermittency factor which even with the battery storage can never be
completely overcome. So more recently a group of visionary entrepreneurs had a bit of a rethink
and decided to see if there were any other more reliable ways in which nature could provide energy
to those difficult to reach communities and in most cases the glaringly obvious answer was the
water flowing nearby in rivers and canals. But surely Dave, you're not advocating yet more dams
on yet more rivers causing yet more damage to the local environment and wildlife are you? No I'm not!
Hello and welcome to Just Have a Think. Now I don't think anyone would seriously suggest
that harnessing the power of water was exactly a new concept. The Greeks were using water wheels
for grinding wheat into flour more than two thousand years ago and that exact same technology
was still in widespread use right up until the dawn of the industrial revolution
not just for making flower but also for sawing timber and pulping paper and running looms to make
textiles. During the 20th century that constantly flowing resource was harnessed at breath taking
scale to drive hydropower turbines and generators producing reliable base load electricity in many
parts of the world. Hydropower doesn't emit any carbon dioxide in operation so on the face of
it it looks like a great option for any region that has a major river with a decent gradient.
The trouble is though that most governments are fixated on extremely large centralized
infrastructure projects that can supply enormous quantities of electricity to national scale
grids, and they're getting bigger. You think the Hoover Dam was impressive at a power generation
capacity of 2,000 megawatts? Well check out the Three Gorges dam in China, completed in 2012,
capable of more than 10 times that output. Enough for tens of millions of
homes offices and factories. There's lots of good logical reasons for this approach of course.
Large infrastructure projects tend to get higher levels of investment from commerce and
industry. Building large in one location is often logistically easier than building small in lots
of different locations, and once they're up and running those grand centralized power generators
can be easily controlled by power companies and regulated by the state essentially providing a
nice neat and tidy monopoly on a commodity that's become essential to our modern way of life. But the
environmental impact of grid scale hydropower is a big concern. Building a dam on a river
means blocking, diverting or completely changing the natural course of the water.
That often screws up the migration routes for species of fish that rely on them to get to
their annual breeding grounds. The consequence of that is a drastic reduction in fish populations
with big negative effects on the ecosystem, including food stocks, for indigenous human beings.
Water-borne sediment flow is also massively reduced which means far fewer nutrients for all
forms of wildlife further along the river system, not to mention the obvious consequence of water
scarcity or even drought for the folks downstream, and damming a river also causes upstream flooding.
The Three Gorges dam caused a flood of around a thousand square kilometres, which is about 80
percent of the entire area of Los Angeles, displacing 1.3 million people as a result.
And several recent studies have shown that organic matter, like dead plants that get trapped in the
reservoirs, break down and release carbon dioxide and methane into the reservoir water. So you know -
not ideal! Here's the ideal shopping list then for several hundred million people living in remote
areas of the world. Small scale locally controlled power generation. Reliable affordable electricity
available 24 hours a day seven days a week. Minimal or even zero environmental impact, and the ability
to hook up to a grid system if it's available or run completely off grid if necessary. All of those
criteria are met by a micro hydropower system developed by a Belgian start-up company called
Turbulent, founded in 2015. I recently spoke with the guys at Turbulent to gain a better
understanding of how their system works. Essentially they've designed what they describe
as a vortex turbine that can work in river systems with a head of water of less than five metres
and as little as a metre and a half from the top of the system inlet to the bottom of the outlet.
A channel gets dug to divert a small portion of the river or canal flow to one side. A sluice gate
and mesh filter are installed at the very start of the channel to regulate the flow of water and to
stop any large debris getting in. Once the sluice gate is opened water flows down into the circular
well where the Turbulent turbine is installed, and as the water passes across the turbine it creates
a low pressure vortex. The low rotation speed turbine blades have soft rounded edges allowing
aquatic life to pass straight through the entire system - possibly somewhat invigorated and keen to
have another go but not harmed in any way at all. All the water and fish are then returned straight
back into the main flow of the river system to continue on their journey entirely unaffected.
So now you've got a spinning turbine driving a generator producing electricity in exactly
the same way as its larger scale hydroelectric cousins. That supply can either be hooked up to
a grid if there's one available or simply run through a standalone electrical consumer unit
to provide power for the building or community that it's been specifically designed for.
The whole thing is controlled autonomously by electronic wizardry in the electrical cabinets
that turbulence engineers install on site, and of course there's an app for it so that all the
performance parameters can be monitored remotely by the turbulent team and the owners of the system.
The smallest installation has a capacity of five kilowatts which in remote areas of developing
nations is enough to supply 50 rural households, plus water treatment at night and businesses
during the day. Larger installations can be up to 200 kilowatts per turbine
and those turbines can be linked up into a network generating multiple megawatts of power.
Off-grid communities get the benefit of effectively free electricity 24 hours a day
365 days a year for the entire lifetime of the turbine, which is rated at 30 years. If they do
decide to get hooked up to the grid then they may even generate a small income through grid 'feed-in'
payments - which brings us nicely to cost. Well the guys at Turbulent pointed out that these are very
much bespoke systems constructed to fit precisely into each selected and carefully surveyed site,
so that means that every project will have its own cost structure, but as a rough rule of thumb
a 15 kilowatt grid tied installation would come in at around 75 000 euros
and a similar off-grid system would be about 90 000. If that was installed in Europe it'd be
enough constant base load power to run 30 typical European homes, which equates to a cost of about
3000 Euros each. Compare that to a typical solar panel installation that could cost as
much as 10 000 euros, and which would only provide intermittent power, and the numbers start to look
pretty favourable. And the larger 50 or 70 kilowatt systems have even better economies of scale than
that. And it really becomes very enticing indeed if you compare it to the cost of diesel, which
is the fuel source that Turbulent will be competing against on most of their projects.
A 15 kilowatt system will be generating 360 kilowatt hours of energy every day. That's
131 400 kilowatt hours every year for 30 years, which is very nearly 4 million kilowatt hours of energy
over the lifetime of the turbine. If you divide that into the off-grid installation cost of
90 000 euros you get a unit cost of less than 2.3 Euro cents per kilowatt hour, compared to a typical
diesel fuel cost of more like 50 Euro cents per unit. That's a pretty compelling business model!
Turbulent now have 10 fully installed or in progress projects at various sites around
the world. This installation in Bali Indonesia was commissioned by The Green School - one of the most
eco-friendly schools in the world and a pioneer of sustainable education. The turbine sits on
the Ayong river, famous for its white water rafting. The system provides the school with about 80 percent
of all its energy requirements, with the rest coming from a small existing solar installation.
The school spent 11 years trying to develop their own micro hydropower system by trial and error .
Their most recent construction was destroyed by a flood that carried debris downstream. So one
of the main design objectives for the Turbulent team was to create mechanical components that
were capable of withstanding whatever our changing climate could throw at them,
including severe flooding. The turbines are all fitted with a fully submersible gearbox
and induction generator with mechanical face seals plus a secondary sealing system
with multiple layers of projection against fresh and brackish water debris and sand,
designed specifically for use in continuous heavy duty harsh environments. All the components for The
Green School were boxed separately and taken to site on the back of a relatively small flatbed
vehicle and because the water diversion channel and the circular vortex well already existed,
installation only took a day to complete without the need for any heavy machinery.
The whole system sits within a nice small neat footprint just outside the school. A solar
installation generating a similar output would have taken up the space of four tennis courts.
One of the key benefits of the constant base load supply of these vortex systems is that they can
run essential services like hospitals and other public buildings that absolutely must guarantee
permanent uninterrupted power. Those institutions currently spend a large amount of their budgets
on diesel generators to ensure the lights and life support systems never switch off. And then
there are commercial businesses like nature parks, eco resorts and agricultural centres
that are often located far from standard power grids but typically very close to a source
of running water making them ideal candidates for these sorts of standalone power generators.
Micro hydropower can be an attractive option for governments as well. Rural electrification
and development programs are a key priority of the United Nations Sustainable Development Goals,
and grants are available for those sorts of initiatives, both from the European Union
and the World Bank. The grand scale hydropower dam projects that I talked about earlier
are horrendously expensive and many are currently on hold in developing nations
as a result of increased project costs. Turbulent turbine projects can be built in phases
to decrease initial investment and risk, and part of the energy can be directly used in
the areas immediately adjoining the site which helps to gain the support of local communities.
Developing and constructing a large-scale hydropower plant can take up to 10 years while
multiple linked up micro hydropower installations can be completed within months and could well have
paid for themselves entirely in less time than it takes to build and commission a dam.
Regular viewers of this channel will know I'm a big fan of these sorts of
lateral thinking approaches to solving some of our planet's trickier problems,
and I for one would love to see many more of these brilliant devices
installed in remote areas around the world. In fact if I ever do retire and realise my own little pipe
dream of a timber framed passive house next to a river in the middle of the woods somewhere,
then I'd be very tempted to invest in one of these things myself! Jump down to the comment
section below to share your thoughts, but that's it for this week. A big 'thank you' to the channel's
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