Blog post

Finding the right combination – using renewables to unlock the base load problem

Energy security in South Africa, 2 April 2024

A favourite Sunday afternoon activity for the Marshall family growing up was a family walk (usually accompanied by the Irish rain to be honest). From time to time, we would venture to some of the hills not far from my parents’ home where we could walk in and around these new and unusual wind parks. And from time to time there would be no turbines turning. How does that work and how is that efficient my father would ask?

Now that’s a while ago and today those same hills have many more turbines, but this question is still one I hear quite frequently and in no doubt has played a role in perpetuating the popular belief that renewable energy is not reliable. I don’t think too many people outside of the energy industry have spent a long time wondering how the electricity grid functions and what goes into it (if you are used to electricity arriving at the flick of a switch, why would you?), but nonetheless this perception persists. And there is some truth to it if we are honest. The wind does not always blow as expected and although the sun rises and falls regularly, cloud cover is not something we have the same level of certainty on when predicting solar generation patterns.

It’s not unexpected then that there continues to be a common mantra of ‘conventional generation for baseload’ even within the energy industry. But what happens when we test this thesis and examine the evidence?

When we at Green Giraffe Advisory began to look at the framework for the South African emergency Risk Mitigation Independent Power Procurement Programme (RMIPPPP) tender a few years ago, it was immediately clear that the process had been designed with conventional generation solutions in mind – although technology neutral, it was asking for dispatchable generation to provide baseload like generation between 5h00 and 21h30 for the lowest bid price possible. However, with our client G7 Renewable Energies for the Oya Energy project, we began to examine the possibility of responding to these needs with a solution fully based around renewable energy.

This wasn’t a unique idea (although the solution combining wind, solar PV, and storage at the same location is) and eventually what came out of this tender process was a list of projects reaching financial close that was dominated by renewable energy-based solutions.

What can we read into this?

Whilst not a silver bullet to the variability brought by renewable energy to a grid, it certainly shows the ability for a single plant with a combined interface of solar, wind and storage (the plant controller playing a vital role behind the meter for these components to then perform their collective role) to provide services to the grid operator at a price which is a competitive (or even more competitive) compared to conventional competitors.

That might not work so well in every geography (it certainly helps that South Africa has great wind and solar resource) and indeed it is likely in many places that it would be more economical to manage such interface and dispatch at the level of the grid. However, that in itself gives rise to the further question as to how a national grid heavy with renewable energy might function.

The duck curve is widely observed and analysed (i.e. the effect on the load throughout the day when there is a mass of solar PV generation in a system). My colleague Michael Ware has already commented here on what this may mean for idea of required baseload from conventional generation. It’s a stretch to argue that one project is a proof of concept, but we think Oya Energy provides a fantastic example of how renewable energy can help provide dispatchable and baseload type generation at a micro-level. Additionally, replicating a project such as Oya Energy in a geography where the overall grid is less developed or there is an energy intensive captive demand could still make a lot of sense.

We are immensely proud of what we achieved on Oya Energy, alongside G7 Renewable Energies and Engie. Not simply because of the addition that makes to cleaner energy security in South Africa but because of the precedent that sets for the use of renewable energy to provide stable power to the grid during a long window. And to be able to blow away (pun intended) some of those persistent old perceptions about renewables at the same time does no harm either.