wind turbines with sun setting

Answering the big renewable question

What do we do when the sun doesn’t shine?

With a parent company who produces more renewable power than any other company in Australia, you can bet we're big renewable fans.

But the question remains: how do you get solar power without sun, or wind power without a suitable gust? This isn’t a trick question – you just don’t. So while the future is renewable, there’s plenty of scepticism around how we plan to get there if the resources we need to generate electricity have a patchy record of showing up for work.

Over 75% of Australia’s energy still comes from burning fossil fuels. Part of the reason we still rely so heavily on coal plants is that much of our renewable energy uses intermittent resources. Wind and solar account for 57.8% of Australian renewables, so when there’s no sun or wind, what do we do? Tell everyone to flick The Bachelor off for a hot second? We’re not monsters.

Nick Sissons, our Head of Emerging Technologies held a talk at the Melbourne International Flower and Garden Show this year. He said “the challenge is you can’t replace coal unless you find a suitable source of on-demand power – wind and solar alone won’t let you do that.”

While coal has never been a sustainable option, it’s made it possible for us to generate power as and when we need it. And given we’re losing a lot of coal-powered plants in the coming years, we need a renewable solution that’s equally as reliable.

How we can make it work with renewables

There are plenty of people out there making sure all’s not lost when the sun goes down. For one thing, there’s battery storage. It lets us save the energy we don’t use at the time it’s generated and access it later. Like taking a doggy bag home from the restaurant.

Plenty of homes already do this on a small scale with rooftop solar and home batteries. But we’re not talking about a ‘stick it on your garage wall’ situation – these are entire farms of batteries so big they need their own fleet of road trains (not trucks – road trains) to get around.

Then there’s pumped hydro – which is kind of like a big (wet) rechargeable battery. Momentum’s parent company, Hydro Tasmania is one generator working on making pumped hydro a part of the solution.

Hydro Tasmania Dam - Lake Gordon
Hydro Tasmania’s dam at Lake Gordon

How does pumped hydro work?

First, water flows downhill to produce hydropower. So far, nothing new. But here’s where it gets smart: the system includes solar and wind power so when it’s sunny or windy, that energy is used to pump the water back up into the reservoir it came from. This usually happens when demand is low, to make sure the dam is ready to go when we need it again.

Learn more about how hydropower works.

The challenges around pumped hydro

Pumped hydro is a work in progress and there are a couple of hurdles. One is that existing dams only work in one direction. We still need to build the infrastructure that pumps water back to the top (and try not to let any engineers hear us make it sound that simple).

Another problem is Australia’s abundance of coal. According to Nick Sissons, the challenge of being the world’s largest exporter of coal is that you end up with a strong coal industry, which has historically made it the go-to for power. But there’s no stopping Nick’s optimism – “despite that, Australia has the largest rooftop solar uptake in the world, and it’s only increasing. In fact, there’s more wind and solar projects in planning right now than we can actually add to the grid”. Sounds like a good problem to have.

If money talks, we’re on the right track

If you’re sick of good news, tune out. Because once it’s established, renewable generation paired with storage is a more cost-effective option than what we’re using today. Good for planets, good for pockets.

There’s no silver bullet, but that’s okay

Nick’s take on how we’ll move towards using more renewable energy is “you’ve got to do lots of different things to get the outcome you want”. And he’s already seen a huge transition towards renewables – mostly driven by solar and wind – that, to him, makes a more renewable Australia inevitable (even on cloudy days).

Where we got our stats:

Clean Energy Australia Report 2019 (Clean Energy Council, 2019).

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