Using the power of the sun... twice.

One of the big benefits of solar energy is that it can provide for a very diverse set of energy needs, as we’re going to hear from our final guest on this week’s show. Richard Randle-Boggis from The University of Sheffield is working with collaborators in Kenya and Tanzania on Agrovoltaics, technologies which aren’t just providing solar energy to remote communities, but may not repurpose land currently used for food production. James Tytko reports...

Richard - Agrovoltaics is actually a pretty simple concept. It's combining agriculture with photovoltaic. So when you visited the solar park, you mentioned the food versus fuel land use crisis those conflicts that we're seeing with developing solar parks. And so what we do with Agrovoltaics is raise the panels up so that you can have agricultural activities underneath and you space the panels apart to let enough sunlight through to the underlying crops. And what that means is that you're getting renewable energy without losing the crop land.

James - It must be quite tricky to balance between making sure the solar panels are receiving enough sunlight to produce a good amount of electricity. And also that the crops are receiving enough light to produce enough food for themselves. How do you manage that?

Richard - Yeah, so it's really important that the Agrovoltaics systems are designed depending on the local context. So in Northern Europe, for example, it is a bit more of a conflict for the light from solar panels and for the crops, but in other places, for example, where I'm working in east Africa and in tropical regions where there's plenty of sunlight it's actually a benefit to partially shade the crops underneath. Whereas if you are in Northern locations, then you need to space the panels apart a bit more. There's also tilting panel technologies, which can tilt the panels away from the sun to let more sunlight through to the crops. But of course that comes at a bit of a cost to electricity production.

James - And if we think first just about those projects you're working on in Africa, what results are you seeing from installing Agrovoltaics in these remote arid communities?

Richard - Well, it's actually really exciting because what we're seeing by partially shading, the crops is that we're reducing water loss from evapotranspiration. We are reducing temperature stresses and UV stresses. And so we're actually increasing the yields of some of the crops that we've grown. We're in the early stages of our studies at the moment. So we need more time to study more crops over a longer period of time. But from one harvest season that we've had so far with cabbages, the cabbages were actually 21%, larger than in the open field control system. So not only are we getting the low carbon and local and also off grid electricity, but also increasing the crop yields as well. And something else I wanted to mention was that you also mentioned about the issue with the temperature affecting the electricity generation. One of my collaborators in the university of Arizona has seen that by raising the panels up and having the crops underneath the solar panels are actually slightly cooler than conventional ground mounted panels as well, increasing their electricity generation. So actually it's benefiting both the food yields and also the electricity production

James - And these communities in Africa where there's a lot of off grid electricity needs is really providing a benefit.

Richard - Yeah, absolutely. So more than half of the population of east Africa. So that's more than 200 million people don't have access to electricity. They're not connected to national grids. And those that are connected to national grids also have issues with blackouts, with the grid being unreliable. And one of the wonderful things about solar technology is that you can provide a range of different scales in many places around the world, which means that you don't need to be focusing on expanding national grids. And you can actually work on off grid and mini grid systems. And this can apply both for Agrovoltaics and also other forms of solar like rooftop solar, and other mini grid systems.

James - This sounds kind of like the opposite of what we were talking to Karim about earlier with these massive solar projects in Morocco designed for Europe's needs. You're working with people internationally still, but this feels like it has a very local focus. I wonder what you think the possibilities of scaling Agrovoltaics, we touched on it a bit before, but using the same method on the vast ways of land in this country currently being used for solar and a bit of grazing as in the case of Vine farm.

Richard - Yeah, absolutely. So firstly, it can be incorporated with grazing as well. But with the Agrovoltaics we look at it aims to take it to another step. So we're not losing those fields of crop land. When you get on the train around the UK and you see those huge fields of solar parks, which are providing much needed, low carbon electricity we are now seeing that we can also produce food underneath those solar panels as well, but there's a loss of work that needs to be done. The systems have been tested in France, Italy, the Netherlands and Germany, but we haven't tested them yet in the UK. So we need to figure out how to design the systems, how spaced apart the panels need to be. And importantly, what will the local communities think about the systems as well? That's a crucial factor when developing an Agrovoltaics system.