How to turn a volcano into a power station – with a little help from satellites

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Erta Ale in eastern Ethiopia. mbrand85

Ethiopia tends to conjure images of sprawling dusty deserts, bustling streets in Addis Ababa or the precipitous cliffs of the Simien Mountains – possibly with a distance runner bounding along in the background. Yet the country is also one of the most volcanically active on Earth, thanks to Africa’s Great Rift Valley, which runs right through its heart.

Rifting is the geological process that rips tectonic plates apart, roughly at the speed your fingernails grow. In Ethiopia this has enabled magma to force its way to the surface, and there are over 60 known volcanoes. Many have undergone colossal eruptions in the past, leaving behind immense craters that pepper the rift floor. Some volcanoes are still active today. Visit them and you find bubbling mud ponds, hot springs and scores of steaming vents.

Steam rising at Aluto volcano, Ethiopia. William Hutchison

This steam has been used by locals for washing and bathing, but underlying this is a much bigger opportunity. The surface activity suggests extremely hot fluids deep below, perhaps up to 300°C–400°C. Drill down and it should be possible access this high temperature steam, which could drive large turbines and produce huge amounts of power. This matters greatly in a country where 77% of the population has no access to electricity, one of the lowest levels in Africa.

Geothermal power has recently become a serious proposition thanks to geophysical surveys suggesting that some volcanoes could yield a gigawatt of power. That’s the equivalent of several million solar panels or 500 wind turbines from each. The total untapped resource is estimated to be in the region of 10GW.

Converting this energy into power would build on the geothermal pilot project that began some 20 years ago at Aluto volcano in the lakes region 200km south of Addis Ababa. Its infrastructure is currently being upgraded to increase production tenfold, from 7MW to 70MW. In sum, geothermal looks like a fantastic low-carbon renewable solution for Ethiopia that could form the backbone of the power sector and help lift people out of poverty.


Scratching the surface

The major problem is that, unlike more developed geothermal economies like Iceland, very little is known about Ethiopia’s volcanoes. In almost all cases, we don’t even know when the last eruption took place – a vital question since erupting volcanoes and large-scale power generation will not make happy bedfellows.

In recent years, the UK’s Natural Environment Research Council (NERC) has been funding RiftVolc, a consortium of British and Ethiopian universities and geological surveys, to address some of these issues. This has focused on understanding the hazards and developing methods for exploring and monitoring the volcanoes so that they can be exploited safely and sustainably.

Teams of scientists have been out in the field for the past three years deploying monitoring equipment and making observations. Yet some of the most important breakthroughs have come through an entirely different route – through researchers analysing satellite images at their desks.

This has produced exciting findings at Aluto. Using a satellite radar technique, we discovered that the volcano’s surface is inflating and deflating. The best analogy is breathing – we found sharp “inhalations” inflating the surface over a few months, followed by gradual “exhalations” which cause slow subsidence over many years. We’re not exactly sure what is causing these ups and downs, but it is good evidence that magma, geothermal waters or gases are moving around in the depths some five km below the surface.

Taking the temperature

In our most recent paper, we used satellite thermal images to probe the emissions of Aluto’s steam vents in more detail. We found that the locations where gases were escaping often coincided with known fault lines and fractures on the volcano.

When we monitored the temperature of these vents over several years, we were surprised to find that most were quite stable. Only a few vents on the eastern margin showed measurable temperature changes. And crucially, this was not happening in synchronicity with Aluto’s ups and downs – we might have expected that surface temperatures would increase following a period of inflation, as hot fluids rise up from the belly of the volcano.

A productive geothermal well on Aluto. William Hutchison

It was only when we delved into the rainfall records that we came up with an explanation: the vents that show variations appear to be changing as a delayed response to rainfall on the higher ground of the rift margin. Our conclusion was that the vents nearer the centre of the volcano were not perturbed by rainfall and thus represent a better sample of the hottest waters in the geothermal reservoir. This obviously makes a difference when it comes to planning where to drill wells and build power stations on the volcano, but there’s a much wider significance.

This is one of the first times anyone has monitored a geothermal resource from space, and it demonstrates what can be achieved. Since the satellite data is freely available, it represents an inexpensive and risk-free way of assessing geothermal potential.

With similar volcanoes scattered across countries like Kenya, Tanzania and Uganda, the technique could allow us to discover and monitor new untapped geothermal resources in the Rift Valley as well as around the world. When you zoom back and look at the big picture, it is amazing what starts to come into view.
This blog is written by William Hutchison, Research Fellow, University of St Andrews; Juliet Biggs, Reader in Earth Sciences and Cabot Institute member, University of Bristol, and Tamsin Mather, Professor of Earth Sciences, University of Oxford

This article was originally published on The Conversation. Read the original article.
Juliet Biggs is a member of the University of Bristol Cabot Institute.  She studies Continental Tectonics and Volcanic Deformation and has won numerous awards in her field.  Find out more about Juliet Biggs research.

Two weeks in the ‘Avenue of Volcanoes’

Workshops, conferences, field work – national and international travel is an essential part of many PhD programs. I’ve been lucky enough to see numerous new parts of the globe during my studies, and, less luckily, numerous different airport layovers (I’m currently writing this post from a corridor between terminals at Washington airport…!).

I’m on my way back to Bristol from a workshop in Ecuador on volcanic unrest, which culminated with an eruption simulation exercise. As my PhD is focused on unravelling the science behind volcanic unrest, these trips (this is the second of three with this specific aim) form a main focus for the real-world application of my research.

This workshop was split into 3 different parts. The first was a series of lectures on how volcanologists, social scientists, emergency managers, civil protection officials, and the general public interact during volcanic crises. Each specialist contributed their individual expertise, in my case as a volcanologist interpreting the signals that the volcano gives off, but the main message was that communication at all times between all parties must be especially clear. As with almost all lectures though, this part of the workshop obviously wasn’t the most exciting – especially with the inevitable jet-lagged tiredness kicking in for the first few days.

The second part of the workshop took us out into the field to explore two of Ecuador’s most famous volcanoes: Cotopaxi and Tungurahua. This was my favourite part! These are two quite epic volcanoes with the classical conical shape you imagine when you think of a volcano. By examining them in situ we learnt about the hazards they pose today to many nearby towns and cities. This really helps to put my research into perspective, as I know that by contributing to a better understanding of how volcanoes work I am helping to protect the people whose livelihood’s depend on the benefits the volcano brings them (for example, the more fertile soil).

Cotopaxi volcano, summit 5897 m ASL

The final part of the workshop took us to the Ecuadorian national centre for crisis management in Quito (cue vigilant security checks!). Here we conducted the volcanic unrest and eruption simulation. This is similar in some ways to a fire drill but a whole lot more complicated. Simulated monitoring ‘data’ from the volcano is fed to a team of volcanologists who have to quickly interpret what the data means and feed that information in a clear, coherent and understandable way to emergency managers, politicians and civil authorities. Upon the advice of the volcanologists, the decision makers can then choose how best to respond and mitigate a potential impending crisis. As this was just an exercise, different stages in the unrest crisis were dealt with all in one very busy day, with ‘data’ from the volcano arriving every couple of hours but representing several weeks or months in simulated time.

The final ‘update’ from the volcano: BIG eruption! I think we all could have predicted that – everyone likes a grand finale.

Despite the Hollywood firework finish, these exercises are crucial to prepare those individuals who will actually be in positions of responsibility when a true volcanic crisis develops. By playing out the different stages in as close to real-life as possible, strengths and weaknesses were highlighted that will allow for improvements to be made in the future. Improvements that may just save extra lives or livelihoods, and foster improved relationships between the public and the scientists trying to help them.

As one of those scientists, I was just happy enough to be able to take part.
Cabot Institute member James Hickey is a final year PhD student in the School of Earth Sciences. His research is focused on unravelling the mechanisms that cause volcanoes to become restless prior to eruptions. Ultimately, the aim is to improve our understanding of precursory signals to enhance forecasting and mitigation efforts.

James Hickey

This blog has been republished with kind permission from the Bristol Doctoral College.  View the original blog post.

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