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Renewable energy explained

What is renewable energy?

It’s energy from 100% renewable and sustainable sources, like wind off the Scottish coast or solar from sunny Spain. It’s called renewable (or sometimes infinite energy) because it can ‘renew’ itself quickly, time and time again.

It’s the greener, cleaner way to power our homes, and has a huge part to play in building a sustainable energy system of the future.

Renewable energy sources

There are many sources of renewable energy, and more and more power companies, like us, are embracing the technology to encourage it. The good news is that it’s predicted to be behind 40% of the world’s power by 2040.

At OVO, renewable electricity comes from a range of green sources, including:

  • Geothermal energy.

  • Hydroelectric power.

  • Solar power.

  • Wind power.

What’s the difference between renewable, green and clean energy?

Renewable energy

Essentially, it’s a energy that can be replenished as fast or faster than it gets consumed. Most renewable energy is green too, although some, like hydroelectric power, for example, can have a small negative impact on fishing or land use.

Green energy plans

These don't simply use renewables. Ofgem, the energy regulator, also asks that 'green energy' plans must offer additional environmental benefits.

Take our Green Energy add-on for example. On top of offering 100% renewable electricity1, we plant 5 trees2 a year for every customer who signs up, which means we're actively fighting carbon emissions across the UK.

Clean energy

This means energy that’s created with minimal use of hazardous chemicals or radiation. It won’t emit carbon dioxide (CO2) pollution. Like green energy, it doesn’t directly threaten plants and animals either.

Some regard nuclear power as clean – it doesn’t produce CO2. However, the uranium mining involved in it does and, if something goes wrong with a nuclear plant, the fallout can be catastrophic and last for generations.

You could argue that ‘clean’ energy is the hardest to define. It’s a pretty broad term.


The opposite of clean energy?

You’ve got it – dirty fossil fuels. This is coal, oil and gas that takes hundreds of millions of years to form. They’re fossils. They can never be replenished or renewed before we use them all up – so burning them is completely unsustainable.


Why is it so important to invest in renewables?

Yes, there could be financial benefits, due to the boom within the industry (it’s growing and looks good for the economy). But the real reason to invest in renewable energy – in the true sense – is to provide a better, healthier future for our planet and everyone in it.

Unlike fossil fuels, renewable electricity simply can’t run out. It’s always there for future generations. And the more we use it, the more we shrink our carbon footprint.


How does renewable energy work?

If you fancy wearing your science hat, you can find out more about about the mechanics of some of the world’s most popular renewables:


Which renewable energy source produces the most energy?

As the UK is extremely windy, especially at sea, and has both a large coastline and shallow water, wind farms are currently able to produce the most energy – renewable or otherwise.

Overall, wind generated more electricity than coal for Britain in 2017. It’s worth noting that solar power did too, most of the time, which makes it a close second.


How is renewable energy stored?

New, innovative technologies are capable of storing renewable electricity, so an abundance of energy doesn’t go to waste.

For example, we’re developing vehicle-to-grid technology, so electric vehicle drivers can store power in their cars and pass it back to the National Grid at peak times when the rest of us need it. We’re also modernising troublesome storage heater batteries with VCharge Heat controls, so these customers can be warm exactly when they want for the first time.

Other storage systems can also be installed in the home. The most established are lithium ion storage batteries – but more systems are on the way, including:

  • Compressed air energy storage.

  • Electricity batteries.

  • Flywheels (rotor energy).

  • Heat batteries.

  • Hydrogen stores.

  • Molten salt.

  • Pumped hydroelectric storage.

  • Thermal stores.


Batteries could revolutionise renewable energy but developing them is key. Helpful then that development is now part of the UK government’s Industrial Strategy, which means developers of renewable batteries will receive funding.

Can renewable energy meet demand?

Not quite yet, as renewables, like wind and solar, are unpredictable. That makes balancing the National Grid – matching the supply of electricity to demand – trickier. But we’re getting there. With the correct infrastructure and storage in place, experts say renewables could power the world by 2050.

At OVO, we’re doing our bit by investing in and developing grid balancing software and storage technology, like electric vehicles and home batteries, to store electricity when it’s abundant – and release it back to the National Grid when demand is high.

It’s the smart way to balance the National Grid and increase green electricity generation, so one day our country can be solely and reliably powered by renewables.


Can renewable energy meet base load power?

With the advent of new batteries, pumped hydro and bio-fuelled gas turbines, energy can be supplied flexibly, 24/7, to meet the demand. Smart technology can also be used to provide power, as the world of energy changes.


How do UK energy companies buy their energy?

To secure the best prices, suppliers like us buy most of our energy on the wholesale market. This gets generated in all sorts of ways.

UK electricity generation mix (for the wholesale market):

  • Coal.

  • Oil.

  • Gas.

  • Nuclear.

  • Hydro.

  • Wind and Solar.

  • Bioenergy.

  • Pumped storage.

  • Other fuels.

  • Net imports (interconnectors).


How we keep it green

The fuel mix at OVO is simple. It’s made up of two things – renewables and natural gas. We don’t use nuclear power, coal or ‘other’ fuels.

We’re really proud that a huge 64.7% of our energy comes from renewables (that’s more than double the UK average). It’s clear proof of our commitment to building a greener, more sustainable energy system for the future.

We’re also chuffed that we’re not responsible for any high level radioactive waste. And that we’ve managed to half our CO2 emissions over the last 3 years, making them well below the national average.

Overall, our fuel mix picture is a positive one, and our customers can feel confident that they’ve made a green choice on all our plans. Better Energy, Simpler Energy and 2 Year Fixed Energy all include 50% renewable electricity3, and that amount can be bumped up to 100% with the Green Energy add-on.


Getting green energy into homes

Whatever way power is generated, it all gets mixed up together on the National Grid – which means no electricity supplier can trace the origins of the actual electricity from generator to customer. Luckily, the UK energy industry uses a certificate called a Renewable Energy Guarantee of Origin. It shows how much renewable electricity it’s bought, versus how much it’s sold to customers. For the same reason, EU member states use GoOs.

So, although we can’t guarantee what ends up in your home will be the exact same renewable electricity we bought for you – no supplier can – we can show that for every unit you use, we’ve bought the equivalent amount of renewable electricity.


Do you think a green future is worth investing in? We hope so – because we certainly do. Our Green Energy add-on is designed to help you do your bit for the planet, while we get to work on paving the way for a cleaner, more sustainable energy system.







1 If you’re signed up to our Green Energy, we purchase renewable certificates for 100% of your electricity use from green sources such as wind, solar, geothermal and hydro. Visit for more information.

We aim to plant 5 trees on your behalf in green spaces over the UK through our I Dig Trees programme. From April 2017 to March 2018 we're aiming to have planted at least 150,000 trees bringing the total number of trees planted to over 500,000 trees since 2015. Find out more about I Dig Trees, here: /i-dig-trees

3 50% renewable electricity as standard as of 1st October 2019. Renewable electricity is generated from wind, solar, geothermal and hydro.

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