Q and A: Imperial engineer talks about new solar energy project in Africa

Dr Christos Markides talks about a volunteer project he is involved in to build up scientific expertise in solar energy in Africa.

Dr Markides, from the Department of Chemical Engineering at Imperial, is a Reader in Clean Energy Processes. He specialises in developing sustainable technologies that use solar energy to generate clean electricity.

Dr Markides talks to Colin Smith about a five-year project he is collaborating on with colleagues from African universities to further develop the skills needed to build concentrated solar power systems.

What is a concentrated solar power system?

Concentrated solar power (CSP) is a way of harnessing the Sun’s thermal energy and converting it into electrical power for consumers. Spain, with its plentiful supply of sunlight, is the world leader in CSP plants, followed by the US.

Can you explain how it works?

There are many different ways to do this, but essentially the specific technology we are considering uses solar collectors spread over a large area to direct and concentrate sunlight that is used to heat up a liquid. This liquid then travels to a power plant where it boils water into steam at high pressure to drive a generator, which in turn produces energy.

How will you be improving on this technology?

Harnessing the Sun’s thermal energy could translate into a new industry for Africans

If we could do away with the stage where the intermediate liquid is heated, and use the solar energy to directly turn the water into steam then there would be a number of advantages, including a higher efficiency and a lower cost. However, there are a number of challenges that we need to overcome to make the technology work. For example, variations in the intensity of the Sun’s rays throughout the day could mean that there is not always sufficient solar energy to heat an adequate quantity of water in order to convert it into steam to power a generator.

If you do overcome the challenges, what are some of the advantages?

Getting rid of one step in the process would make it more energy efficient. A higher efficiency means we could shrink the size of concentrated solar power plants, while still delivering the same electricity to consumers. One of the current drawbacks of these plants is that the solar collector area, the so-called ‘solar field’, need lots of space, thousands of acres of land. Doing away with heating the liquid could enable engineers to shrink the technology. In the future, we may be able to have affordable mini-solar power systems for homes or businesses, which could be a major benefit in regions that don’t have much infrastructure.

Simplifying the technology could also make it more robust. This would be another advantage for developing countries that might not have the critical mass of expertise to run and maintain these plants.

Are you working on any projects in this field?

The Royal Society and the Department for International Development have funded a project that aims to build up the academic expertise in the field of concentrated solar power technology in Africa. Imperial is leading this project and we are volunteering our services because we think it is a really important initiative to be involved in. This is part of a wider initiative by the Royal Society and the Department for International Development, which is funding ten flagship projects, to build up African expertise in a range of scientific and engineering fields.

What is the project’s scope?

Essentially, there are two main aims. The first involves establishing partnerships and carrying out the necessary underpinning multidisciplinary research with academic institutions in sub-Saharan Africa. We are working with the Universities of Pretoria in South Africa, which has a strong research base in solar energy, along with the Universities of Lagos, in Nigeria, and the University of Mauritius, Mauritius. The specific concentrated solar power technology we are developing in this project is also a new area for my research group to get involved in. So we are all learning on this project.

The second aim involves building up research and training capacity in the region.

What does capacity building entail?

Through the transfer of knowledge and skills, we are helping our collaborators build up a strong and research capacity base, while supporting a cohort of young, talented African researchers through PhD scholarships. We know that a strong research base can lead to many opportunities such as new businesses and a positive impact on the economy, society and people.

We hope that by the end of the project there will be established and self-sustaining research networks in these countries that will be capable of undertaking high-quality, international-level research and of taking part in similar projects with a global reach.