The future is renewable because it has to be to avoid the worst impacts of climate change and meet our net zero emission ambitions, we need to decarbonise. 

A good place to start is electricity. Electricity accounts for a quarter of Australia's greenhouse gas emission. Therefore, it's crucial to tackle this sector so that we can achieve our goals of Net Zero by 2050, using the cheapest forms of clean energy, solar and wind. 

These technologies have become the cornerstone of our decarbonisation strategy, but to get to net zero emission we're going to need a lot of them. 

Data from the International Energy Agency suggests we'll need four times as much wind and solar power by the end of this decade as we had at the start.

But no technology lasts forever, and eventually all of these new renewables will become old waste. So what do we do about it?

To understand how we can reuse renewables, we need to know how to make them. 

These are complex technologies that require specific, pure, and often rare materials. 

Solar panels need high quality silicon. Wind turbines need rare earth elements, and batteries require lithium. 

You hear critical minerals being bandied around all the time. So generally we would call those things critical minerals. It's stuff that you need that you might not be able to get. 

Critical minerals aren't only used for renewables, but pretty much every renewable needs some kind of critical mineral that's left countries scrambling to secure a steady supply. 

As demand for renewables skyrockets, and we all saw what happened in COVID, suddenly we discovered that supply chains were really fragile and originated in one place. 

And if that one place shut down nobody could get anything. 

So we really need to do more processing in Australia to create jobs. We'll be creating diversified supply chains, but getting renewable technologies is only part of the solution.

When the sun doesn't shine and the wind doesn't blow, we still need to keep the lights on. 

So how do you get renewable power on demand? 

You could turn to hydrogen thermal or a range of other energy storage technologies, or you could turn to the compact piece of energy storage sitting in your front pocket, the lithium ion battery in your smartphone. 

Without the use of batteries, we have a very great difficulty in being able to generate energy when we don't have sun or when we don't have wind. 

Batteries are a critical piece of infrastructure in order to make sure we have energy over the durations of time, we need it. These tiny batteries work on the same scientific principle as the big ones in electric vehicles and home battery storage.

As you've no doubt noticed with your old phone, lithium ion batteries degrade over time. 

That leads to a significant e-waste. In Australia alone, battery waste could exceed 136,000 tons by the middle of next decade. 

What happens with that? Globally, it's estimated just 5% of batteries are recycled with much of the rest ending up in landfill.

That can wreak havoc on the environment. Leaking toxic metal ions into soil and groundwater and starting fires that can easily spread. 

We really need to educate consumers to understand more about what it is that they have in their pockets and when they're using electronic devices, to know that they have batteries there and that they do need to be take care of these devices and don't compromise them, such as leaving them in hot environments or putting them near, ignition sources or other dangerous environments.

Right now, most battery waste comes from personal devices, and these are relatively easy to recycle with public collection points at shopping centres and other venues. 

But it's considerably more difficult to recycle larger batteries like those in EVs. CSIRO’s lithium battery shredder pilot plant aims to demonstrate this more complex recycling at scale.

Even if we can improve our battery recycling, there's another problem hanging over our heads or more accurately on our roofs - Solar Panels. 

Australia has among the highest uptake of rooftop solar in the world with millions of panels spread right across the country. Those panels will eventually die contributing to a global waste pile that may exceed 70 million tons by 2050.

So what do we do with them now? 

They have about a 10 to 25 year lifetime, depending on how they're installed and where they're installed. And they hold a lot of critical metals and minerals. It's been estimated that if we could recycle just the raw materials by 2050, that would represent $20 billion worth of raw materials.

The easiest part of solar panel recycling is found in the glass, so most processes focus on that. There's a wealth of valuable components in the rest of the panel, but recovering them can be a challenge. 

The back of a solar module is usually made with poly vinyl fluoride, which if reshaped could be used in batteries or other technology, but traditional recycling considerably heats that PVF creating harmful per and poly fluoro alcohol substances or PFAS. 

Researchers are investigating non-volatile solvents, which can reduce these emissions and allow the reuse of solar PVF. 

We've developed methods to separate the different components of the solar panel safely. 

So for example, the fluorinated polymers from the back sheet, but we've also been able to recover the silver component, the valuable components of the solar panels, and that makes it very attractive for industries. 

Rigorous standards on solar deployment don't just affect solar panels at the end of their lives. In Australia, solar modules lose their certification if they're moved, which can add perfectly functional panels to the solar stockpile.

CSIRO researchers are developing portable testing systems and working with standards bodies to ensure that functioning panels don't end up in the scrap heap. 

We are doing projects where we demonstrate that you can take panels and create a very good system of reuse, but that's pilot scale or small scale at the moment.

The issue that we're talking about is that by 2030 or by 2050 the number of panels is in the millions. 

Circularity is also an emerging concern for wind farms as some of the earliest farms approach their end of life. Many parts of a wind turbine are readily recyclable. Steel, aluminium, copper, and cast iron all have mature pathways to a second life.

But the iconic blades of the turbine are more difficult to deal with. Manufacturers are developing new materials and methods to recycle these old components. 

But circularity means that recycling turbines in good condition can be redeployed, offering pathways for small businesses and to developing economies to decarbonise.

And in Europe, old blades have been repurposed, turned into public bus stops, seating, and even playgrounds. Net zero is a massive challenge. We're going to need innovation and novel thinking to tackle these emerging issues, such as the waste from renewables, but there can be great benefits from a coordinated circular economy approach to solve these and create new businesses and industries.

There's no way around it. The transition to clean renewable energy will require a significant increase in the mining and processing of critical minerals manufacturing and deployment. 

Nothing lasts forever, but by working smarter, we can turn the renewables of today into renewables for decades to come.