Kirk Fellowship Interview: Professor Claudia Sagastizabal on renewable energy, the “science of betterment” and punting in circles

Designed to support and promote underrepresented groups in mathematics, the Kirk Distinguished Visiting Fellows scheme was launched at the start of 2019 and so far boasts five senior academics amongst its recipients. In this latest interview from its roster of honourees INI spoke to Professor Claudia Sagastizabal of the “Mathematics of energy systems” programme.

Claudia Sagastizabal, firstly: can you tell us about the meaning of your fascinating surname?
It’s a Basque name, it means “big apple tree orchard”, “sagasti” is “apple tree orchard” and “zabal” is “big”. I didn’t, however, grow up in Spain. My grandfather left to find opportunity in the Americas, and that’s where I was born: in Cordoba in Argentina. Then I came back to Europe to find opportunities for study. Now, however, I’m associated with Campinas University in the Brazilian state of Sao Paulo… and I studied for my PHD in France.

And today you find yourself at INI in Cambridge. How do you feel about being a speaker in the “Mathematics of energy systems” programme?
It is a great opportunity to meet colleagues that I already know, but also to get to know others from other disciplines, such as economics. It’s also very enrichening and stimulating to meet new colleagues from the UK – INI is a rich environment to be part of. Our first workshop was very long and intense and full of full days of hour-long talks, but it’s very interesting to discuss the challenges of the new paradigms in energy supplies as we move towards sustainable sources – such as wind – and encounter the changes this means for business.

How does your specialism relate to this?
I work in numerical optimisation, focusing on applications within the energy sector. This comes from my PHD of more than 20 years ago. A part of my PHD work is being used every day by Électricité de France to determine how much energy will be produced in each of their utilities for the next day.

That must be a source of great pride for you.
I’m very happy, yes. I always think that when you’re a scientist or researcher you’re very happy when you’re work is evaluated and eventually published. But when you do applied mathematics they use what you have written – so it needs to function! So there is one “step forward” and this is really useful for the theoretical insight you get from really touching down with the application.

So many of your workshop colleagues will be familiar with this aspect of your work?
Well, what I really want to exchange with them is “know how” and ideas to address the future challenges.

How does optimisation differ in this sector from other spheres?
Optimisation is the science of “betterment”. You need to do something in “the best possible way”. This doesn’t mean that something is necessarily the best from every point of view. For example: you have to pick the ingredients for paint so that it best sticks to the wall. So you have to optimise the product to perform in this way. Electricity optimisation can tell you how best to produce energy from different sources, such as nuclear, gas, wind, hydroelectric (the latter of which is particularly true in Brazil). In the case of wind, you have to use the energy or you lose it. But, when it is in use you are not producing using another source, so your water reservoir will be full when the wind ceases to produce. So you have to bear in mind the different flexibilities and capabilities of the sources you have available. You also have to consider maximising social welfare or reducing generation costs… so you have to find the best solution in each case.

You have a unique insight into energy systems across the world. What’s happening globally in your field?
It’s a revolution. You have all those new sources that generate power, but it’s useless to generate power if it’s not then taken to the consumption centres. You don’t care if there’s wind in Scotland if when you turn the switch in Cambridge there’s no light. Somebody has to bring it. And this transmission via distribution networks has been changed, from a business point of view, by the rise of renewables. The other, older sources produce constantly – so you can see that we’re paying a toll for using renewables. Wind, for example, produces inconsistently so it can suddenly cause a traffic jam in the network when it does. This is something that has to be addressed. We have to think again about all of these systems so that all the renewable, cheap electricity that is good for the long-term can be brought in a reliable manner to the consumption centres.

And this is why it’s interesting to interact with so many peers from across the world?
The interesting thing for me is that usually we are very busy, we run around and don’t stay in any one place for long. But here we have more time. And there are participants here from many different areas, and what you notice is that academics from different fields, for example economists, face the same problems but explain them in a slightly different manner than a mathematician or an engineer. So it’s really very enrichening. It’s very nice.

You’re one of the inaugural Kirk Distinguished Visiting Fellows, which is aimed at celebrating mathematicians from underrepresented groups. How do you feel about that?
I feel very honoured to have received this Fellowship. I think it’s important for the visibility of the types of mathematics that can be done when you follow through theory into practical application. That’s purely on the technical side. On the human and social side it has been interesting for me over the past years as I’ve increasingly had a very public profile. I’ve had, in both Brazil and Europe, ladies coming to me and saying “it’s important for us to see that somebody like you can succeed in this career”. I’ve realised now, without ever having been a militant of this kind of thing, that I’ve become some sort of role model. This adds another dimension to my responsibilities. It does have an effect. When I take a student, for example, if it’s a girl I will try perhaps harder to “make this happen”. I have a bias, it’s true. I cannot have it very often though, as we’re not so many!

What proportion of your colleagues and students are women?
Less than 20 per cent. Perhaps with the undergrads it’s 50/50. But then many of them stay in the business of teaching and don’t go into research. Perhaps 25 per cent go into research. And this gets worse as you get higher. In the decision-making committees you will not have enough female vision. Having a gender mixture in such bodies functions a complement, it doesn’t have to introduce opposition. It’s a way of providing other views for the long-term good of an institution – for example with regards to hiring particular people. But without this balance it’s not always easy for women to be heard.

What do you think causes this drop-off?
To begin with many women don’t think it’s possible to have a standard family life with a successful career. It’s not easy, but the fact that there are some women that can is inspiring for girls at the beginning of their careers.

So is your increasing visibility a good thing?
I think yes. In a way it’s a surprise. I’ve never looked for this kind of information from girls around me, but they now come to me and tell me of their concerns. And even with women further in their careers who want advice on how to get a position on boards or in groups made up only of men. Possibly I can help them with some advice – but not “female” advice, you understand, mathematical advice! Because experience counts, and I try to transmit experience.

What else can be done to redress the gender imbalance in mathematics?
I think this is a long-term goal. I see now the young generation of men as very different to what I knew in my time. Even when I go back to South America, which has always been a very “macho” land, things are changing and this is the driver. It’s like when you try to convince a smoker to stop smoking: they have to be convinced by themselves. It doesn’t matter if they’re “obliged”. We have to work together, men and women, to achieve this goal. And it’s likely to happen because the young generation is much more aware of this issue.

And how have you found life in Cambridge?
This is my second time, and what’s interesting is that 10 years ago I came as an accompanying person! So I was enjoying the tourism. I very much like University cities. They’re effervescent. And I appreciate this because I come from a similar city in Argentina. I also went punting… and I didn’t fall in. I mostly turned in circles. I found the pole a little heavy as it’s made just of wood. So it was a little heavy for my size, but I managed. In fact I enjoyed it. Everyone was offered the chance and I accepted the challenge. So you see I’m a woman who is used to a fight!