What is renewable energy?

Renewable energy is energy that’s generated using renewable resources - like wind, water or the sun. You might also know it as green energy or alternative energy.

Where do I find it?

You’ll find renewable power plants in places that make it easy to use the renewable resource they need to generate electricity. Which means no dams in deserts, and no solar plants in caves. Sorry, eco-bats.

How is it different from non-renewable energy?

Non-renewable energy is generated using resources we only have a certain amount of, or that take tens to hundreds of millions of years to form - you’d know most of these as ‘fossil fuels’.

Ever since it became a big deal, electricity has been generated by burning fossil fuels, which are not only finite but also highly pollutive - around a third of our greenhouse gas emissions in Australia come from electricity generation.

Coal is a non-renewable resource

What are non-renewable resources?

Firstly, there’s fossil fuels ­- oil, coal and natural gas that are formed over millions of years from the buried remains of plants and animals. (Like these colossal, surprised-looking prehistoric fish.) Then there’s uranium (made from zero deceased animals as far as we know), which we mine to use for nuclear energy.

What are renewable resources?

Anything that’s replenished frequently enough to be used over and over, like wind, water and sun. With the right infrastructure, they can be used to generate electricity. They’re not the only renewable sources of energy, though - plenty of others are being used to generate electricity all over the world.

Types of renewable energy

Barring things like the niche exploration into jellyfish goo (a real thing you can Google yourself), here’s a list of renewable resources being used around the world right now.

Solar power

Sun is one of the most reliable renewable energy resources - and it isn’t going away any time soon. When the sun shines, solar panels use energy from sunlight to generate electricity (how? Read What is solar energy?)

A recent addition to solar power generation comes from a pretty unexpected place – right next to the No.4 nuclear reactor in Chernobyl (you know the one). That’s where they’ve installed no fewer than 3,762 solar panels that are now making electricity for Ukraine.

So in 2018 (and for the first time since the No.3 reactor was shut down in 2000,) electricity started coming out of Chernobyl again. According to Solar Chernobyl, the plant produces 1.02gWh of electricity per year. A modest amount, but name one other unliveable disaster zone that’s made itself so useful.

Wind power

To get power from wind, we use turbines. Turbine blades catch the wind, which makes them spin, which in turn powers an electricity generator. Read What is wind energy? if you’re into the details.

Wind turbines need a few things to work efficiently. They need to be spaced far enough apart so that they’re not affected by turbulence from wind hitting surrounding turbines. Naturally, they need the right amount of wind too - enough to get the turbines spinning without getting caught on anything too strong. Which is why the Havøygavlen wind farm in northern Norway makes absolutely no sense.

It’s stationed on a coastal headland with winds so high that some turbines have lost rotors, and one has even fallen down entirely. Ever the optimists, engineers there have taken the conditions as an opportunity. They’re using it to find out exactly what it takes to operate in such challenging conditions, with a view (we assume) to making some sort of SuperTurbine™.*

Bioenergy

Bioenergy is kind of the original energy. Ever seen wood burning? You’re an expert already.

The thermal energy you get from burning biofuel can be used directly (in other words: fire), or you can use it in the same way as coal is used to boil water, create steam and spin turbines.

Finland is the main bioenergy generator, with plans to make 30% of their electricity from biofuel by 2030. There, they use byproducts from wood processing (like chips and bark), but biofuel can come from all sorts of places: bagasse (a fancy-sounding word for what’s left over when sugar is extracted from the cane), landfill gas, energy crops (grown specifically to make energy), household waste and agricultural products.

In terms of sustainability, bioenergy is a little like the less cool sibling of the other renewable energy types. In theory, there should be a closed carbon loop - where whatever is emitted by burning should be absorbed when you grow the next crop. The problem is a lot of traditional biofuels are grown unsustainably and they burn inefficiently (meaning less bang for your greenhouse gas emission buck). So making sure we choose the right biofuels is key.

Hydropower

Boy, wouldn’t it be cool if an energy source just… fell from the sky?

Water is a go-to for renewable energy, especially in areas where sunlight isn’t as abundant. Hydroelectricity is generated from spinning turbines, using the force of falling water that’s released from a dam when needed.

Most of Australia’s renewable energy comes from hydropower, with Hydro Tasmania being the largest generator of clean energy in Australia – all out of tiny Tassie. They’re the main source of electricity for Tasmanians, and also trade on the National Energy Market (NEM) which the electricity they generate goes to other parts of Australia too.

Geothermal

Under the Earth’s surface, there’s a hell of a lot of heat. Just sitting there - up for grabs. And it can be used just as it comes for interior heating, or for making electricity.

Some geothermal heating systems are made simply by bringing hot groundwater to the surface. Others send water from the surface down to be heated, and bring it back up again. The hot water gets carried into homes through pipes that in turn heat the room. As for electricity, we can use geothermal in places where the underground water temperature is particularly high - by using the steam it produces to spin turbines, the same way as coal-fired plants do.

Geothermal energy has relied on technological advancements to become more widely used (try drilling holes a mile deep with that cordless drill you got for your birthday). Which is why the establishment of the first generator - in Lardarello, Tuscany ­- is so neat. It started supplying electricity commercially in 1913 and was used to power the central Italian electric railway system. So you could say geothermal energy has moved a lot of cabooses in its time.

Tidal

Tidal energy works by holding water using a barrage at a tidal inlet (imagine a mostly solid bridge that lets water through at certain points). When the tide comes in or out, gates in the barrage close to create a difference in water levels on either side (like a dam) - so when they open, water flows to re-establish equilibrium, spinning turbines in the process.

Tidal power plants haven’t been explored to the same extent as other renewable energy sources. Mostly because their limitations are the big ones: cost (compared to the more mainstream wind and solar) and environmental implications – barrages disrupt natural water flow which can affect the surrounding ecosystem. But for any enthusiasts in need of reassurance, there’s still a lot that makes tidal energy an interesting prospect. Using the tides means output is easier to predict (thanks, moon) and the density of water means it doesn’t have to move as fast to spin a turbine as wind does.

The world’s first tidal power plant was built at the mouth of the Rance river in France in 1966 and generates more than 500GWh of electricity a year. Its turbines were designed to work in both directions so the plant could take advantage of incoming and outgoing water during spring tides. The barrage (that also functions as a bridge) is over 700m long and was probably considered ‘très cool’ when it saved locals on coastal jaunts a trip around the estuary.

How do we use renewable energy?

Renewable energy is used in the same way as energy from fossil fuels. That’s because electricity is just a current of charged particles (they say the simple ideas are the best ones). We can get that current going in a whole lot of ways, which is why there are so many different examples of renewable energy.

If, like most people, you’re connected to the power network, there’s no way of telling where the electricity in your home came from. That’s because it’s supplied by different generators ­- some that use renewables, and others that don’t. Lucky for you, all you need is that flow of electrons and you’re ready to go.

Renewable energy advantages

The benefits of renewable energy are pretty significant:

  • Cleaner
    When we burn fossil fuels we emit carbon dioxide into the atmosphere - a leading cause of climate change. Renewable energy doesn’t create these emissions (except in the case of burning biofuel).
  • Infinite
    Once you use a non-renewable source, that’s it, it’s gone. But the wind, sun or rain? They’ll come back again and again. (Maybe several times a day if you happen to live in Melbourne.)
  • Cost-effective
    Once a renewable system is set up, the resource needed to generate energy is more or less always freely available on-site. No need to buy it, no need to transport it (with the exception of biofuel).

How to use renewable energy at home

In Australia, it’s not as simple as deciding to use renewable energy in your home. In most cases, you’ll be connected to the National Electricity Market (or the ‘grid’). Electricity from both renewable and non-renewable sources is mixed in the grid and we all get our energy from this same pool.

But there are a few ways you can support renewables at home.

Installing solar panels to provide some (or even all) of your usage is one way to make your home greener. If you’re not in a position to do that, you can still make a difference by choosing an energy company that supports renewables, or a plan that lets you offset some or all of your usage. Maybe you’ll even feel incrementally better about paying your power bill. Maybe.

Want to get a little more renewable-friendly?

We’re owned by Australia’s largest renewable generator, Hydro Tasmania.

* This isn’t our trademark, it’s a dicey creative flourish which I hope my editor lets me keep.

Psst. Where’d you get all that info?

Australia’s Rising Greenhouse Gas Emissions (Climate Council, 2018)
Fossil Fuel (Encyclopaedia Britannica, 2019)
Uranium (Encyclopaedia Britannica, 2019)
Solar Chernobyl
The Chernobyl Disaster: Legacy and Impact on the Future of Nuclear Energy (Wil Mara, 2010)
Conquering the Arctic (Recharge News, 2013)
Benefits of Bioenergy (Victoria State Government, 2017)
Finland Sets 30% Biofuel Commitment for 2030 (Biofuels International, 2019)
Alholmens Kraft
What is Bioenergy and Energy from Waste? (ARENA, 2019)
Resources, Conversation and Recycling (Elsevier, 2009)
Clean Energy Australia Report 2019 (Clean Energy Council, 2019)
Energy in Tasmania Report 2017-18 (Office of the Tasmanian Economic Regulator, 2018)
Geothermal Energy: Utilization and Technology (Dickson, 2003)
Geothermal Energy – History (Encyclopaedia Britannica, 2018)
100 Years of Geothermal Power Product (Lund, 2005)
Tidal Power (EDF, 2019)
South Korea’s Plans for Tidal Power: When a “Green” Solution Creates More Problems (Ko, Schubert, 2011)
The Causes of Climate Change (NASA, 2019)