Another one bites the dust

Concentrated solar is the latest non-solution to the intermittency challenge

In 2011, the Jemalong solar-thermal plant was promoted as a glimpse of the future: a bold renewable experiment using mirrors and molten sodium to produce solar power around the clock.

Today, the experiment lies in pieces on the plains of central NSW, 30 km west of Forbes. Vast Renewables, the company behind the project, entered administration last November, leaving the multimillion-dollar facility partially dismantled and abandoned.

The Jemalong Concentrated Solar Power (CSP) experiment was supposed to fix renewable energy’s enduring flaw: intermittency. Yet after 15 years and $9.9 million in government grants, it proved to be an epic flop.

Its failure set the stage for broader questions about the reliability of renewable energy.

The challenge of matching weather-dependent generation to a grid that must balance supply and demand every second remains unresolved.

Over the past decade, policymakers have promised a succession of technological solutions to this problem. However, none has delivered at the scale required to power a modern electricity system, and the Energy Minister is running out of nascent technologies to talk up.

Chris Bowen was spruiking concentrated solar technology as recently as three years ago, when he announced a $65 million grant to the now-defunct Vast Renewables for a CSP at Port Augusta.

“We know that the sun doesn’t always shine,” Bowen told ABC South Australia. “But this enables you to store it… You can then turn it on at any time of the night, and it’s available. That’s the real beauty of this technology.”

With the collapse of Vast, the Port Augusta plant will join the long list of failed solutions to the intermittency problem. So too has green hydrogen, the technology Bowen promised would allow us to be “exporting that sunshine to the rest of the world”.

Green hydrogen was supposed to bridge the gap between intermittent renewable energy and the industrial economy, allowing the production of green steel, green concrete and industrial-scale fertilisers.

Producing hydrogen from renewable electricity requires substantial amounts of power, and converting it back into usable energy involves significant losses. Would-be investors, including Fortescue, BP and Origin Energy, have walked away.

Yet Bowen refuses to give up on his quest to beat the laws of physics and force weather-dependent energy sources to deliver power on demand.

This week, he slipped out of Parliament House to help ACT Chief Minister Andrew Barr switch on the latest community battery in the Canberra suburb of Dickson.

“People say the sun doesn’t always shine,” said Bowen, “but the rain doesn’t fall every day either… we drink water every day because we store it for when we need it, and we can store renewable energy as well.”

Community batteries are expensive and have limited storage capacity. At the 2022 election, Labor promised to build 400 of them around the country, each serving an average of 250 households.

Four years later, it has delivered 109. The Dickson battery will serve just 45 households in a suburb where household income is 30 per cent higher than the national average.

How long would the batteries last? asked one journalist. That depends, replied Bowen. “Normally, batteries can support several hours’ worth of energy.”

That will be little reassurance to families in Canberra, where the sun sets around 5pm in mid-winter and average overnight temperatures hover around zero degrees centigrade.

Despite years of investment, the fundamental issue persists: the intermittency challenge remains unsolved, much as it was in 2007 when Kevin Rudd set ambitious renewable targets.

Expansive hopes for concentrated solar and hydrogen as storage solutions have come to nothing. Pumped hydro remains technically viable but extremely expensive and slow to build. Projects like Snowy 2.0 face years of delays and billions in cost overruns, while the transmission lines needed to connect new renewable zones can take a decade to plan and build

Bowen would have us believe that the answer to our troubles is batteries. Last July, he launched the Cheaper Home Batteries Program, allocating $2.3 billion to give a 30% on the cost of installing a battery system.

By December, the program’s cost had blown out to $7.2 billion, largely due to a policy design flaw: the subsidy structure paid more for larger batteries, prompting consumers to install bigger batteries than necessary.

In December, the government announced urgent changes to the scheme to avoid a much larger blowout. This week, it was reported that the subsidies are being reviewed as part of Jim Chalmers’ efforts to rein in spending in May’s Budget.

Batteries at grid scale and at the domestic level are proving useful at stabilising short-term fluctuations in a grid. By themselves, however, they cannot solve the intermittency problem in the National Electricity Market because of scale, duration, and economics.

The NEM consumes roughly 200 terawatt-hours of electricity each year and frequently requires 25–35 GW of continuous power.

Yet the largest storage facility in the country, the problem-plagued Waratah Super Battery, will be little more than a shock absorber, smoothing out short-term grid fluctuations. South Australia Hornsdale Power Reserve stores about 194 MWh of energy — enough to run the NEM for only a few seconds at full demand.

For all the technological optimism surrounding the energy transition, the basic system constraint remains the same as in 2007. A reliable electricity grid requires generation that can be dispatched whenever demand arises. Until a practical and economical way is found to store vast quantities of energy for long periods, intermittency remains a structural feature of wind and solar rather than a solved engineering problem.