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What makes electricity green?

Tuesday, 18 May 20217 minute read
Sustainability
Energy Industry

What does green really mean? In this blog, we explain what green electricity is, how it’s made and why it’s better than power that pollutes.

Photo by Peggy Sue Zinn on Unsplash

All Pure Planet’s Members, whatever their tariff, are buying 100% green electricity – and, if on the gas network, all their gas is fully carbon offset gas too. But what does green really mean? In this blog, we’ll explain what green electricity is, how it’s made and why it’s better than power that pollutes.

What does green really mean?

Green electricity is power that’s produced from renewable sources, like sun, wind and water. Generating electricity in this way has a much lower environmental impact than fossil fuels like coal and gas because it utilises the natural energy created by our planet. It’s referred to as renewable for that reason too, because there isn’t a limited resource.

The renewable electricity mix

Here at Pure Planet, our electricity mix was 89% wind and 11% sun last year (April 2019-March 2020), with a small amount of hydro used too.

Compare that to the UK’s average fuel mix – according to thinktank Ember, 42% of the UK’s electricity was renewable in 2020 (generated by wind, sunlight, water and wood), compared with 41% generated from gas and coal plants.

For the first time, renewables were the main source of the UK’s electricity over the year.

We’ve still got a way to go, but things are certainly moving in the right direction, and our Members are helping Britain move towards a more sustainable future.

How is green electricity produced?

Photo by Andreas Gücklhorn on Unsplash

There’s a number of different ways that green electricity is produced:

Wind

Wind turbines are popping up around the UK – as of December 2020 there were 10,930 either onshore or offshore. Onshore wind is the most cost-effective of all new electricity in the UK.

It’s cheaper than gas, nuclear and coal, as well as other renewables, including offshore wind. That’s because onshore wind turbines are buried in the ground instead of the seabed, and it’s much easier to service them too.

But not everyone likes them, especially if they’re in the field next door, so the government has incentivised offshore wind farms, which can produce even more electricity than their onshore counterparts, but they are more expensive to build and operate. In fact, the UK is leading the way, with more offshore wind turbines than any other country.

This map shows where renewable energy is being generated in the UK. The green dots show wind farms. You may be able to see some of the larger offshore farms from the shore, including the Rampion which is visible from Brighton beach – at 72 square kilometres this wind farm is larger in size than Guernsey. Further north, the Humber Gateway offshore wind farm can be found 8km off the East Yorkshire coast. And Gwynt y Môr, which has the capacity to generate enough energy to power 400,000 homes, can be found eight miles off the North Wales coast.

Credit: Interactive map of renewables. Copyright Carbon Brief 2020

Solar

Despite the amount of rain we see here, solar is another popular source of green energy in the UK. There’s an ever-growing range of solar technology, but essentially they all do the same thing – capture the sun’s light and convert it into electricity. This electricity can then be fed into the National Grid, or into your home if you have your own solar panels, for example on your roof.

Did you know that it takes 8 minutes for the sun’s light to reach Earth? All the sunlight striking the Earth’s surface in just one hour would deliver enough electricity to power the world’s energy needs for a year.

It’s worth bearing in mind though that, as with most things, solar comes with its downsides too, and solar intermittency is one of its biggest criticisms. Since solar relies on the sun, electricity can’t be generated at night, so we need to store excess energy made during the day or use alternative sources. An overcast day will also reduce the amount of power made, too.

Hydro

Hydroelectricity is electricity generated by the movement of water. This water is used to spin a turbine. It’s reliable (no breaks in supply when the sun’s not shining) and flexible because the flow of water can be controlled and altered depending on demand. But, it’s very expensive to get set-up, and the areas you can build a hydro plant are limited.

At Pure Planet, we source some of our renewable electricity from a small hydro plant at Black Corrie, near Strontian in Scotland. Some of the biggest hydroelectric power stations in the UK can also be found in Scotland, as well as in Wales.

We’ve talked about hydro energy on the blog before. Take a look at this post here.

Biomass

Biomass is any organic material which has absorbed sunlight and stored it as chemical energy. Wood and waste from farms and forests are all examples of biomass. Bioenergy is energy made from biomass, and there’s a few different methods for this generation including:

  • Thermal conversion – this is where heat is used to upgrade the biomass to a better fuel (like when you burn logs in a woodburner to warm your home)
  • Biochemical processes – this is where biomass is broken down by microorganisms, for example through composting or fermentation, to create bioenergy.

Geothermal

Geothermal energy is energy that’s extracted from the Earth itself. More specifically, it’s the heat that naturally flows to the Earth’s crust. Being a Bath-based company, we know all about geothermal energy – Bath (or Aquae Sulis as it was once known) was built here in Roman times because of its geothermal spring, which raises water temperatures to between 69 and 96 °C.

Geothermal energy isn’t much used in the UK, but that doesn’t mean it won’t develop over time. The UK government has set ambitious targets and is supporting projects with funding.

And just down the road from us in Bristol, renewable energy investment company Thrive Renewables is investing £6.5 million in British geothermal energy. So you can expect to hear a lot more about geothermal energy in the years to come.

What’s so wrong with energy that’s not green?

Photo by ETA+ on Unsplash

Aside from renewable energy sources, the electricity we use in the UK is produced by burning fossil fuels like gas and coal, or through nuclear reactors. You’ll sometimes hear energy generated in these ways referred to as ‘dirty’*.

Here’s why:

  1. It’s warming our planet to dangerous levels – greenhouse gases like carbon dioxide are emitted when fossil fuels are burned to create electricity. These emissions trap heat in the atmosphere leading to climate change
  2. It’s polluting our air – burning fossil fuels can cause toxic air pollution, some of which has been linked to cancer
  3. It’s destroying our land – unearthing and using fossil fuels and uranium uses vast swathes of land,destroying it and the wildlife that lives there in the process
  4. It’s contaminating our water – acid runoff, radioactive particles and oil spills are just a few of the byproducts contaminating our waters thanks to dirty energy
  5. It’s producing radioactive waste – when energy is generated through nuclear reactors radioactive waste is produced. This can’t simply be thrown away. Instead it’s buried deep underground or stored in huge drums at surface-level.

*Nuclear power is sometimes referred to as low carbon, like green electricity. But unlike renewable energy, it can have a grave impact on the environment – at Pure Planet, we don’t buy from nuclear generators.

In the coming weeks we’ll be sharing more blogs explaining where and how we buy the energy supplied to our Members’ homes, including an in-depth look into REGOs.

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Alexandra
Digital Content Creator