Researchers found 37 mine sites in Australia that could be converted into renewable energy storage. So what are we waiting for?

Shutterstock Timothy Weber, Australian National University and Andrew Blakers, Australian National University

The world is rapidly moving towards a renewable energy future. To support the transition, we must prepare back-up energy supplies for times when solar panels and wind turbines are not producing enough electricity.

One solution is to build more pumped hydro energy storage. But where should this expansion happen?

Our new research identified more than 900 suitable locations around the world: at former and existing mining sites. Some 37 sites are in Australia.

Huge open-cut mining pits would be turned into reservoirs to hold water for renewable energy storage. It would give the sites a new lease on life and help shore up the world’s low-emissions future.

The benefits of pumped hydro storage

Pumped hydro energy storage has been demonstrated at scale for more than a century. Over the past few years, we have been identifying the best sites for “closed-loop” pumped hydro systems around the world.

Unlike conventional hydropower systems operating on rivers, closed-loop systems are located away from rivers. They require only two reservoirs, one higher than the other, between which water flows down a tunnel and through a turbine, producing electricity.

The water can be released – and power produced – to cover gaps in electricity supply when output from solar and wind is low (for example on cloudy or windless days). And when wind and solar are producing more electricity than is needed – such as on sunny or windy days – this cheap surplus power is used to pump the water back up the hill to the top reservoir, ready to be released again.

Off-river sites have very small environmental footprints and require very little water to operate. Pumped hydro energy storage is also generally cheaper than battery storage at large scales.

Batteries are the preferred method for energy storage over seconds to hours, while pumped hydro is preferred for overnight and longer storage.

Pumped-hydro storage technology has been demonstrated at scale for over a century. Shutterstock

Why mining sites?

There are big benefits to converting mining areas into pumped hydro plants.

For a start, the hole has already been dug, reducing construction costs. What’s more, mining sites are typically already serviced by roads and transmission infrastructure. The site usually has access to a water source for which the mine operators may have pumping rights. And the development takes place on land that is already cleared of vegetation, avoiding the need to disturb new areas.

Finally, community support may have already been obtained for the mining operations, which could easily be rolled over into a pumped hydro site.

In Australia, one pumped hydro energy storage project is already being built at a former gold mine site at Kidston in Far North Queensland.

The feasibility of two others is being assessed at Mount Rawdon near Bundaberg in Queensland, and at Muswellbrook in New South Wales. Both would repurpose old mining pits.

What we found

Our previous research identified suitable locations in undeveloped areas (excluding protected land) and using existing reservoirs. Now, we have turned our attention to mine sites.

Our study used a computer algorithm to search the Earth’s surface for suitable sites. It looked for mining pits, pit lakes and tailings ponds in mining sites which were located near suitable land for a new upper reservoir. The idea is that the reservoir and mining site are “paired” and water pumped between them.

Globally, we identified 904 suitable mining sites across 77 countries.

Some 37 suitable sites are located in Australia. They include the Mount Rawdon and Muswellbrook mining pits already under investigation.

There are a number of potential options in Western Australia: in the iron-ore region of the Pilbara, south of Perth and around Kalgoorlie.

Options in Queensland and New South Wales are mostly located down the east coast, including the Coppabella Mine and the coal mining pits near the old Liddell Power Station. Possible sites also exist inland at Mount Isa in Queensland and at the Cadia Hill gold mine near Orange in NSW.

Potential sites in South Australia include the old Leigh Creek coal mine in the Flinders Ranges and the operating Prominent Hill mine northwest of Adelaide. Tasmania and Victoria also offer possible locations, although many other non-mining options exist in these states for pumped hydro storage.

We are not suggesting that operating mines be closed – rather, that pumped hydro storage be considered as part of site rehabilitation at the end of the mine’s life.

If old mining sites are to be converted into pumped hydro, several challenges must be addressed. For example, mine pits may contain contaminants that, if filled with water, could seep into groundwater. However, this could be overcome by lining reservoirs.

Looking ahead

Australia has set a readily achievable goal of reaching 82% renewable electricity by 2030.

The Australian Energy Market Operator suggests by 2050, this nation needs about 640 gigawatt-hours of dispatchable or “on demand” storage to support solar and wind capacity. We currently have about 17 gigawatt-hours of electricity storage, with more committed by Snowy 2.0 and other projects.

The 37 possible pumped hydro sites we’ve identified could deliver 540 gigawatt-hours of storage potential. Combined with other non-mining sites we’ve identified previously, the options are far more numerous than our needs.

This means we can afford to be picky, and develop only the very best sites. So what are we waiting for?

Timothy Weber, Research Officer for School of Engineering, Australian National University and Andrew Blakers, Professor of Engineering, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More........→February 29, 2024

A 380-million-year old predatory fish from Central Australia is finally named after decades of digging

Harajicadectes cruises through the ancient rivers of central Australia ~385 million years ago. Brian Choo Brian Choo, Flinders University; Alice Clement, Flinders University, and John Long, Flinders University

More than 380 million years ago, a sleek, air-breathing predatory fish patrolled the rivers of central Australia. Today, the sediments of those rivers are outcrops of red sandstone in the remote outback.

Our new paper, published in the Journal of Vertebrate Paleontology, describes the fossils of this fish, which we have named Harajicadectes zhumini.

Known from at least 17 fossil specimens, Harajicadectes is the first reasonably complete bony fish found from Devonian rocks in central Australia. It has also proven to be a most unusual animal.

Meet the biter

The name means “Min Zhu’s Harajica-biter”, after the location where its fossils were found, its presumed predatory habits, and in honour of eminent Chinese palaeontologist Min Zhu, who has made many contributions to early vertebrate research.

Harajicadectes was a fish in the Tetrapodomorpha group. This group had strongly built paired fins and usually only a single pair of external nostrils.

Tetrapodomorph fish from the Devonian period (359–419 million years ago) have long been of great interest to science. They include the forerunners of modern tetrapods – animals with backbones and limbs such as amphibians, reptiles, birds and mammals.

For example, recent fossil discoveries show fingers and toes arose in this group.

Devonian fossil sites in northwestern and eastern Australia have produced many spectacular discoveries of early tetrapodomorphs.

But until our discovery, the poorly sampled interior of the continent had only offered tantalising fossil fragments.

A long road to discovery

Our species description is the culmination of 50 years of tireless exploration and research.

Palaeontologist Gavin Young from the Australian National University made the initial discoveries in 1973 while exploring the Middle-Late Devonian Harajica Sandstone on Luritja/Arrernte country, more than 150 kilometres west of Alice Springs (Mparntwe).

Packed within red sandstone blocks on a remote hilltop were hundreds of fossil fishes. The vast majority of them were small Bothriolepis – a type of widespread prehistoric fish known as a placoderm, covered in box-like armour.

Scattered among them were fragments of other fishes. These included a lungfish known as Harajicadipterus youngi, named in honour of Gavin Young and his years of work on material from Harajica.

There were also spines from acanthodians (small, vaguely shark-like fish), the plates of phyllolepids (extremely flat placoderms) and, most intriguingly, jaw fragments of a previously unknown tetrapodomorph.

The moment of discovery when we found a complete fossil of Harajicadectes in 2016. Flinders University palaeontologists John Long (centre), Brian Choo (right) and Alice Clement (left) with ANU palaeontologist Gavin Young (top left). Author provided

Many more partial specimens of this Harajica tetrapodomorph were collected in 1991, including some by the late palaeontologist Alex Ritchie.

There were early attempts at figuring out the species, but this proved troublesome. Then, our Flinders University expedition to the site in 2016 yielded the first almost complete fossil of this animal.

This beautiful specimen demonstrated that all the isolated bits and pieces collected over the years belonged to a single new type of fish. It is now in the collections of the Museum and Art Gallery of the Northern Territory, serving as the type specimen of Harajicadectes.

The type specimen of Harajicadectes discovered in 2016. Author provided

A strange apex predator

Up to 40 centimetres long, Harajicadectes is the biggest fish found in the Harajica rocks. Likely the top predator of those ancient rivers, its big mouth was lined with closely-packed sharp teeth alongside larger, widely spaced triangular fangs.

It seems to have combined anatomical traits from different tetrapodomorph lineages via convergent evolution (when different creatures evolve similar features independently). An example of this are the patterns of bones in its skull and scales. Exactly where it sits among its closest relatives is difficult to resolve.

Artist’s reconstruction of Harajicadectes menacing a pair of armoured Bothriolepis. Artist: Brian Choo

The most striking and perhaps most important features are the two huge openings on the top of the skull called spiracles. These typically only appear as minute slits in most early bony fishes.

Similar giant spiracles also appear in Gogonasus, a marine tetrapodomorph from the famous Late Devonian Gogo Formation of Western Australia. (It doesn’t appear to be an immediate relative of Harajicadectes.)

They are also seen in the unrelated Pickeringius, an early ray-finned fish that was also at Gogo.

The earliest air-breathers?

Other Devonian animals that sported such spiracles were the famous elpistostegalians – freshwater tetrapodomorphs from the Northern Hemisphere such as Elpistostege and Tiktaalik.

These animals were extremely close to the ancestry of limbed vertebrates. So, enlarged spiracles seem to have arisen independently in at least four separate lineages of Devonian fishes.

The skull of Harajicadectes seen from above, showing the enormous spiracles. Author provided

The only living fishes with similar structures are bichirs, African ray-finned fishes that live in shallow floodplains and estuaries. It was recently confirmed they draw surface air through their spiracles to aid survival in oxygen-poor waters.

That these structures appeared roughly simultaneously in four Devonian lineages provides a fossil “signal” for scientists attempting to reconstruct atmospheric conditions in the distant past.

It could help us uncover the evolution of air breathing in backboned animals.

Brian Choo, Postdoctoral fellow in vertebrate palaeontology, Flinders University; Alice Clement, Research Associate in the College of Science and Engineering, Flinders University, and John Long, Strategic Professor in Palaeontology, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More........→February 27, 2024