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

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?The Conversation

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........

Think you’re good at multi-tasking? Here’s how your brain compensates – and how this changes with age

Arlington Research/Unsplash Peter Wilson, Australian Catholic UniversityWe’re all time-poor, so multi-tasking is seen as a necessity of modern living. We answer work emails while watching TV, make shopping lists in meetings and listen to podcasts when doing the dishes. We attempt to split our attention countless times a day when juggling both mundane and important tasks.

But doing two things at the same time isn’t always as productive or safe as focusing on one thing at a time.

The dilemma with multi-tasking is that when tasks become complex or energy-demanding, like driving a car while talking on the phone, our performance often drops on one or both.

Here’s why – and how our ability to multi-task changes as we age.

Doing more things, but less effectively

The issue with multi-tasking at a brain level, is that two tasks performed at the same time often compete for common neural pathways – like two intersecting streams of traffic on a road.

In particular, the brain’s planning centres in the frontal cortex (and connections to parieto-cerebellar system, among others) are needed for both motor and cognitive tasks. The more tasks rely on the same sensory system, like vision, the greater the interference.

The brain’s action planning centres are in the frontal cortex (blue), with reciprocal connections to parietal cortex (yellow) and the cerebellum (grey), among others. grayjay/Shutterstock

This is why multi-tasking, such as talking on the phone, while driving can be risky. It takes longer to react to critical events, such as a car braking suddenly, and you have a higher risk of missing critical signals, such as a red light.

The more involved the phone conversation, the higher the accident risk, even when talking “hands-free”.

Having a conversation while driving slows your reaction time. GBJSTOCK/Shutterstock

Generally, the more skilled you are on a primary motor task, the better able you are to juggle another task at the same time. Skilled surgeons, for example, can multitask more effectively than residents, which is reassuring in a busy operating suite.

Highly automated skills and efficient brain processes mean greater flexibility when multi-tasking.

Adults are better at multi-tasking than kids

Both brain capacity and experience endow adults with a greater capacity for multi-tasking compared with children.

You may have noticed that when you start thinking about a problem, you walk more slowly, and sometimes to a standstill if deep in thought. The ability to walk and think at the same time gets better over childhood and adolescence, as do other types of multi-tasking.

When children do these two things at once, their walking speed and smoothness both wane, particularly when also doing a memory task (like recalling a sequence of numbers), verbal fluency task (like naming animals) or a fine-motor task (like buttoning up a shirt). Alternately, outside the lab, the cognitive task might fall by wayside as the motor goal takes precedence.

Brain maturation has a lot to do with these age differences. A larger prefrontal cortex helps share cognitive resources between tasks, thereby reducing the costs. This means better capacity to maintain performance at or near single-task levels.

The white matter tract that connects our two hemispheres (the corpus callosum) also takes a long time to fully mature, placing limits on how well children can walk around and do manual tasks (like texting on a phone) together.

For a child or adult with motor skill difficulties, or developmental coordination disorder, multi-tastking errors are more common. Simply standing still while solving a visual task (like judging which of two lines is longer) is hard. When walking, it takes much longer to complete a path if it also involves cognitive effort along the way. So you can imagine how difficult walking to school could be.

What about as we approach older age?

Older adults are more prone to multi-tasking errors. When walking, for example, adding another task generally means older adults walk much slower and with less fluid movement than younger adults.

These age differences are even more pronounced when obstacles must be avoided or the path is winding or uneven.

Our ability to multi-task reduces with age. Shutterstock/Grizanda

Older adults tend to enlist more of their prefrontal cortex when walking and, especially, when multi-tasking. This creates more interference when the same brain networks are also enlisted to perform a cognitive task.

These age differences in performance of multi-tasking might be more “compensatory” than anything else, allowing older adults more time and safety when negotiating events around them.

Older people can practise and improve

Testing multi-tasking capabilities can tell clinicians about an older patient’s risk of future falls better than an assessment of walking alone, even for healthy people living in the community.

Testing can be as simple as asking someone to walk a path while either mentally subtracting by sevens, carrying a cup and saucer, or balancing a ball on a tray.

Patients can then practise and improve these abilities by, for example, pedalling an exercise bike or walking on a treadmill while composing a poem, making a shopping list, or playing a word game.

The goal is for patients to be able to divide their attention more efficiently across two tasks and to ignore distractions, improving speed and balance.

There are times when we do think better when moving

Let’s not forget that a good walk can help unclutter our mind and promote creative thought. And, some research shows walking can improve our ability to search and respond to visual events in the environment.

But often, it’s better to focus on one thing at a time

We often overlook the emotional and energy costs of multi-tasking when time-pressured. In many areas of life – home, work and school – we think it will save us time and energy. But the reality can be different.

Multi-tasking can sometimes sap our reserves and create stress, raising our cortisol levels, especially when we’re time-pressured. If such performance is sustained over long periods, it can leave you feeling fatigued or just plain empty.

Deep thinking is energy demanding by itself and so caution is sometimes warranted when acting at the same time – such as being immersed in deep thought while crossing a busy road, descending steep stairs, using power tools, or climbing a ladder.

So, pick a good time to ask someone a vexed question – perhaps not while they’re cutting vegetables with a sharp knife. Sometimes, it’s better to focus on one thing at a time.The Conversation

Peter Wilson, Professor of Developmental Psychology, Australian Catholic University

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

Read More........