Are iron-flow batteries the solution to variable renewables?

For the first time Australia’s main electricity grid reached a share of over 70% for renewable energy this week, an achievement that showcases the rapid rise of solar and wind generation, but also highlights several challenges.

Australia is a world leader in renewable electricity generation and has the world’s highest penetration of rooftop solar systems per capita.

At around 1.05pm Australian Eastern Daylight Time on Oct. 24 the grid that supplies the five of the nation’s six states was powered by 72.5% renewables, with solar and wind providing 70.9% and hydro the other 1.6%.

That may sound like a remarkable achievement in a country that until recently was largely powered by coal, but it could have been even higher, possibly above 90%.

The reason total generation from renewables didn’t reach over 90% on Oct. 24 was that some renewables were curtailed, largely due to negative wholesale electricity prices, according to the website Renew Economy.

The rising share of renewables illustrates a wider problem for Australia’s grid, and those in other countries that are also seeking to transition away from fossil fuels.

Australia generates excess solar during the middle of the day, which in turn forces the ageing fleet of coal-fired generators to ramp down, before they ramp up again as the sun sets and renewable generation slides.

There are solutions to this, and all of them are variations on the theme that as the grid is fed by more and more variable renewables, you need fast-acting and variable backups.

In Australia this role has fallen to natural gas-fired peaking plants, battery storage and hydropower.

Natural gas, while cleaner than coal, still emits carbon and ultimately isn’t a long-term solution if the goal is to reach net-zero electricity generation.

Solar power expected to dominate electricity generation by 2050 – even without more ambitious climate policies

In pursuit of the ambitious goal of reaching net-zero emissions, nations worldwide must expand their use of clean energy sources. In the case of solar energy, this change may already be upon us.

The cost of electricity from solar plants has experienced a remarkable reduction over the past decade, falling by 89% from 2010 to 2022. Batteries, which are essential for balancing solar energy supply throughout the day and night, have also undergone a similar price revolution, decreasing by the same amount between 2008 and 2022.

These developments pose an important question: have we already crossed a tipping point where solar energy is poised to become the dominant source of electricity generation? This is the very question we sought to address in our recent study.

Our findings, which were obtained by plugging the latest technological and economic data from 70 regions across the globe into a macroeconomic model, suggest that the solar revolution has, indeed, arrived. Solar energy is on track to make up more than half of global electricity generation by the middle of this century – even without more ambitious climate policies.

The good times are over – how Eskom managed to suspend load shedding for so long

Power utility Eskom announced on Sunday that load shedding is back in full swing, with outages returning at stage 2 and stage 3 until further notice.

On Sunday (29 October), the group said that stage 2 load shedding would be implemented from 16h00, lasting until 16h00 on Monday.

After this, stage 2 and stage 3 load shedding would be rotated in the familial pattern (stage 3 from 16h00 to 05h00 and stage 2 from 05h00 to 16h00) indefinitely.

This ends the longest streak of no load shedding since permanent outages started at the tail end of 2022.

According to independent energy analyst Pieter Jordaan, last week represented the best performance in over 400 days.

“The 7-day blackout trend touched the 0%-mark on Thursday, 26 October and remained there for three days. This is the metric’s first ‘landing’ after ‘taking off’ on 6 September 2022, some 416 days prior.”

However, Jordaan noted that this milestone wasn’t necessarily a result of any significant turnaround at Eskom (even though its performance has been improving) but was only made possible by exceptionally low demand and considerable peaking effort by the Systems Operator.

“For context: (the prior week) required 118 GWh of peaking energy but (last week) had already recorded 223 GWh of peaking by Friday.

Ultimately, Eskom employed double the annual average level of Open Cycle Gas Turbine peaking last week to make the extended suspension possible.

Eskom’s stronger performance over the past few weeks has largely been thanks to lower demand. However, with colder weather hitting the country this week, the demand profile is changing.

Demand during the weeks of suspension have tracked far lower than the typical profile, and also lower than the same periods in 2021 and 2022.

This lower demand has been attributed to both a more conscientious consumer and a major boost from rooftop solar installations, which have doubled this year so far.

Credit is also due to Eskom, which has been improving plant performance. The group’s Energy Availability Factor has improved to over 60% for the first time in 2023 and is currently better than comparable periods in 2021 and 2022.

However, the improved EAF is no panacea, as it is still far below the minimum set by energy regulator Nersa (65%) and the group is still not producing enough power to meet ‘typical’ demand – so it continues to operate on that knife’s edge.

Sebenzana APP releases “Springbok inspired” team video

High-value energy and industrial asset performance experts, Sebenzana APP, have released a “Springbok inspired” team video that calls on their skilled electricity and energy asset engineering experts to share what truly motivates them to “move the needle” in terms of the performance of energy and power assets across the continent.

A recent Springboks video “For South Africa (Part 1) that was released on social media channels two months ago, tells of the personal and sometimes quirky reasons why the Springboks are so committed to achieving success for South Africa in France in 2023.


“As energy and power asset engineering practitioners in the trenches, we are daunted by the challenges that South Africa and other countries on the continent face!  Our teams are digging deep and giving a lot of themselves to improve infrastructure that enables society,” says Andrew Carr, Managing Director, Sebenzana APP.


“Like so many other South Africans, we’ve been inspired by how the Springboks openly acknowledge our difficulties as a country and are leading us all to achieve the very best we can while keeping those that we care most about firmly in our minds,” Carr concludes.

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