South Africa needs over 28 GW of flexibility to reach 100% renewables at lowest cost

By Oke Peter
Wärtsilä launches agile balancing technology – capable of ramping up to 10+ MW in two minutes – to bridge South Africa to renewable energy future

The technology group Wärtsilä has highlighted a striking need to scale up flexibility in South Africa, in the form of energy storage and flexible gas technology, to enable a 100% renewable energy future.
28 GW of flexible assets are needed for South Africa’s energy systems to run on 100% renewable energy at the lowest cost. The capacity needed to balance South Africa’s switch to grids powered by intermittent renewables must come from two key technologies: over 21 GW of energy storage and over 6.8 GW of flexible gas power capacity, capable of running on future fuels. Future fuels can be produced during periods when renewables produce more electricity than is needed.

Smart Energy vision, night time

Wayne Glossop, South Africa Business Development Manager, Wärtsilä Energy, said: “Last month’s UN climate report gives a clear message for South Africa: to decarbonise at the lowest cost, high levels of renewable energy must be scaled up by 2030. What we have learned from modelling over 145 countries and regions in our Atlas of 100% Renewable Energy is that power systems with high levels of renewables need a significant amount of flexibility, through energy storage and gas balancing technology, to achieve the transition to 100% renewable energy future.

“By building high shares of renewables, we can create the conditions to produce carbon-neutral Future Fuels that can decarbonise all energy intensive sectors, from power to mobility. To solve this final piece of the net-zero puzzle, the answer once again is to urgently build more renewables, supported by future-proof flexibility solutions.”

South Africa’s need for 28GW of agile flexible solutions reflects the country’s exceptionally high potential to meet its demand almost exclusively with wind and solar energy, and the requirement for significant power storage capacity when wind and solar is no longer generating.

To meet South Africa’s clear need for grid flexibility, Wärtsilä has today launched grid balancing technology – capable of ramping up to 10+ MW in two minutes – to bridge utilities to a 100% renewable energy future at the lowest cost.


Wärtsilä’s grid balancing technology is part of a portfolio of products designed to cost effectively accelerate the energy transition. The portfolio consists of power plants, energy storage and energy management systems. The first power plant solution in the portfolio is powered by the upgraded Wärtsilä 34SG Balancer engine, optimised for renewable baseload markets; an agile, fast-starting gas engine capable of ramping up to 10.8 MW in two minutes to seamlessly integrate with renewables. The power plant solution is based on lean design, and it can be equipped with features such as unmanned standby, remote control capabilities, 24/7 data streaming and dynamic power management. Optimised performance and reliability are supported by Wärtsilä Lifecycle solutions.

Cape Town aerial after sun set.

Wärtsilä’s power plant gas engines can currently run on natural gas, biogas, synthetic methane or hydrogen blends. The company is actively developing the combustion process to allow the burning of 100% hydrogen and other future fuels. Wärtsilä has a long track record of successful fuel conversions for the global installed engine base.

A significant degree of overcapacity is needed to account for the variability of wind and solar generation. Excess electricity is then utilised to produce future fuels with Power-to-X technology. The modelling finds that balancing the intermittency of the renewable production with a combination of flexible gas and energy storage would be 38% cheaper for the G20, in comparison to relying on energy storage alone.

Alongside the power plant solution, Wärtsilä offers its fully integrated GridSolv energy storage technology, designed for ease of deployment and sustainable energy optimisation, and its GEMS Digital Energy Platform. GEMS dynamically optimises energy systems through a broad range of applications, like frequency regulation, to create revenue streams and enhance grid/system resilience.

Jukka Lehtonen, Vice President for Technology & Product Management at Wärtsilä Energy, said: “Currently, the industry is in a challenging situation. Investments need to be made today even if visibility of the future is not fully clear. We have developed, in an agile manner, a solution based on existing, proven technology which is future-proof and flexible. The solution can be adapted to different operational profiles and running hours, along with evolving needs of the system. Using our solution, renewables can be integrated seamlessly into different energy mixes as they become available.”

The modelling on the G20’s comprehensive need for flexibility is based on Wärtsilä’s Atlas of 100% Renewable Energy, which shows the cost-optimal capacity mix for 100% renewable electricity systems in 145 countries and regions around the world.

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