A guide to renewable energy

Using renewable energy to power your home or business can help to reduce your carbon footprint and even cut your electricity bills. Learn more about renewable energy and start comparing green-energy tariffs today.

Using renewable energy to power your home or business can help to reduce your carbon footprint and even cut your electricity bills. Learn more about renewable energy and start comparing green-energy tariffs today.

Sofia Hutson
From the Energy team
minute read
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Posted 7 DECEMBER 2020

What is renewable energy?

Renewable energy is generated from a source that’s naturally replenished – for example, wind, water and sunlight. It can quickly renew itself, so we’ll never run out of it.

Energy produced from natural resources offers an environmentally friendly alternative to energy from fossil fuels, helping you to lower your carbon footprint.

What are fossil fuels?

Fossil fuels such as oil, gas and coal also come from natural sources. They’re formed from the remains of dead plants and animals. They take hundreds of millions of years to form and can’t be replaced; once they’re used up, we’ll have nothing left to burn.

And there’s more bad news: fossil fuels release dirty, harmful carbon emissions that are clogging up the air we breathe. Burning fossil fuels creates the largest source of emissions from carbon dioxide, which – in terms of greenhouse gases that contribute to global warming – is one of the main offenders.

To help fight climate change we’ll eventually need to phase out traditional fossil fuels and move towards cleaner and greener energy sources.

Is there a difference between green energy and renewable energy?

For most of us, the two phrases mean the same thing. But there is a slight difference.

Renewable energy is classed as energy that comes from a natural resource that is quickly and easily regenerated. For example, wave and tidal energy is something that naturally occurs and never runs out, whereas coal and oil are the result of millions of years’ worth of natural organic production.

The idea behind green energy is to be entirely eco-friendly, leaving no impact on the environment. So, while all green energy is renewable, not all renewable energy is green.

So, if in order to build a hydro-electric dam or wind farm you need to clear a large area of forest, or use a large amount of fossil-fuelled energy to build and install the supply, you could argue that it’s not really that green.

What does green-energy tariff mean?

Having an energy tariff that is labelled ‘green’ doesn’t guarantee that your energy is actually supplied through renewable or green sources. Your supply may still be fuelled by the burning of coal.

What it does guarantee is that your supplier is buying in this form of energy, which is essentially a promise to offset the carbon produced through green-schemes – eg: reforestation projects somewhere on the planet.

How much renewable energy is generated in the UK?

In 2019, 12.3% of the UK’s available energy came from renewable sources. Also, in 2019, renewable electricity represented 37.1% of the total electricity generated in the UK.

Bioenergy is the leading source of green power in the UK, accounting for two-thirds of our energy demands, while energy generated from wind power is responsible for nearly 23% of our green energy.  

Under the EU Renewable Energy Directive, the UK’s target for production and consumption of green energy is set at 15% for 2020.

When compared to the rest of the world, the UK is among those leading the way in renewable energy production. In 2019, we were second only to Germany with the highest proportion of renewable energy.

What are the different types of green energy?

There are four types of renewable energy already being used to power homes and businesses in the UK:

  1. Solar energy
  2. Wind energy
  3. Wave and tidal stream energy
  4. Biomass energy

1. Solar energy
This is where light energy from the sun is used to generate electricity and heat water.

Advantages of solar energy Disadvantages of solar energy
Clean energy that’s sourced every day Performance depends on weather
Cheap to maintain once installed Expensive to install
Can save money on your energy bills Needs a lot of space

How does solar energy work? 

Sunlight is made up of tiny packets of energy called photons. Solar energy works by absorbing this energy and converting it into electricity that can be used to power your home or business.

Solar panels use what’s called photovoltaic (PV) cells to absorb the sun’s energy. They turn the energy into direct current (DC) energy, which is converted into a usable alternating current (AC) that can be used to power most devices in your home.

There are also solar thermal systems that are used to heat water.

Residential solar panels are more than 50% cheaper now than they were in 2011. That makes them a great option for home and business owners who want to generate their own power.

Did you know?

Solar energy is the most abundant energy source on the planet, because the sun shines down every single day. Anywhere the sun touches could be converted into solar power.

Find out more about solar panels

2. Wind energy

Wind turbines convert energy from wind pressure into electricity.

Advantages of onshore wind energy Disadvantages of onshore wind energy
Cheaper renewable energy source Performance depends on weather
Easy to install Wind farms take up a lot of land
Installation has minimal environmental impact They can be an eyesore for some


Advantages of offshore wind energy Disadvantages of offshore wind energy
Wind is stronger and more consistent offshore More expensive to install
Doesn’t take up any land More expensive to maintain and repair
Is no longer an eyesore  

How does wind energy work? 

Wind turbines can be used to convert energy from wind pressure into electricity. Huge propellers turn like a fan in the moving air, powering an electric generator to produce a current of usable electricity.  

In 2019, onshore and offshore wind made up 54% of renewable electricity generation, making it the largest source of renewable electricity in the UK.

Wind power has huge potential when it comes to green energy. Prime Minister Boris Johnson says that, based on current electricity use, offshore wind will produce more than enough electricity to power every home in the country by 2030.

Did you know?

The UK is the windiest country in Europe. Roughly 40% of all wind energy generated over Europe blows across blustery Britain.

Find out more about wind turbines

3. Wave and tidal stream energy

This uses moving water to spin a turbine, either in a dam or underwater, to produce a constant flow of electricity.

Advantages of wave energy Disadvantages of wave energy
Produces lots of consistent energy Very expensive to install
Cheap to maintain Impacts marine life
UK has lots of coastline to use  

How does tidal energy work? 

Wave and tidal power is generated using large underwater turbines. These rotate with the ebbing and flowing of the moving water to create energy. The turbines are connected to electrical generators that turn this kinetic energy into electricity, which we can use.

Tidal and wave power is a cheap and generally consistent way of generating renewable power, with the potential to supply up to 20% of the UK’s electricity needs.

Did you know?

Tidal energy is the oldest form of renewable energy. It was used by the Romans when they occupied Britain to power water mills.

Find out more about tidal energy

4. Biomass energy

This uses plant material or animal waste as a sustainable solution to burning fossil fuels.

Advantages of bioenergy Disadvantages of bioenergy
Entirely carbon neutral Still releases greenhouse gases
Reduces waste Can be expensive
Large and consistent supply Requires greater input

How does biomass energy work?

Biofuels can be made from many sources, from food waste to algae and sugarcane. Even human and animal waste can be used to generate biomass energy. It’s used as a low-carbon alternative to fossils fuels. Unlike carbon-based fuels like petrol and coal, biofuels are renewable and produce fewer greenhouse gases when burnt.

One of the main uses for biofuels in the UK is as an alternative transport fuel. Vegetable oil, animal fat and recycled grease can be turned into biodiesel, which can replace normal diesel in cars, trucks and ships. The government’s Renewable Transport Fuel Obligation (RTFO), introduced in 2008, encourages the transport sector to supply renewable fuels that meet sustainability standards.

Find out more about biomass energy

Is natural gas renewable? 

Natural gas is a fossil fuel in liquid form, so although it’s naturally occurring, it’s not renewable.

Although natural gases are cleaner than other fossil fuels like coal, they still produce some carbon emissions. Even biomethane, a renewable natural gas, doesn’t produce energy that’s 100% green.

How does nuclear energy work? 

Nuclear energy is generated by splitting uranium atoms in a process called fission. This produces heat used to turn water into steam, turning huge turbines and generating electricity in much the same way as a wind turbine.

Nuclear power does not produce any carbon or other greenhouse gases, so it’s generally considered to be a clean source of energy.

Is nuclear power a sustainable resource? 

Though considered a clean source of energy, there’s debate about whether the nuclear power can be called ‘sustainable’.

The process of generating nuclear energy doesn’t produce carbon waste, but it does produce radioactive pollutants that can take decades – and sometimes thousands of years – to become safe enough to dispose of. Intensive clean-ups are necessary when decommissioning disused power plants. This means that nuclear power is viewed by many as an unsustainable source of energy.

How does renewable energy meet demand?

In June 2019, the UK became the first major economy to pass a net zero emissions law. This set a target for the UK to bring all greenhouse gas emissions to net zero by 2050. Net zero essentially means carbon-neutral, whether that’s through clean energy production, or the balancing of greenhouse gas emissions against an equal amount removed from the earth’s atmosphere.

While the potential is there for renewable energy to meet the country’s demand, the issue is how we harness the energy effectively enough. We need to integrate this clean energy into the national grid at a rate that is consistent enough to meet demand, especially at its peak (typically the evenings).

Current green-energy suppliers do feed into the national grid, but consistency is an issue because green-energy sources, such as solar and wind, need enough sunlight and wind to power them, which can’t be guaranteed. Tidal energy is more consistently reliable, but we’re still unable to control the waves.

The Committee on Climate Change (CCC) has said that achieving net zero emissions is achievable but “highly challenging”. It’ll involve changes to several public sectors, and that this will be a complicated and expensive process, which will take many years.

How is renewable energy stored?

As the UK continues to strive for a greener future, the way renewable energy is stored becomes increasingly important. While renewable gas is still in its relative infancy, electricity is a different story.

A problem with renewable electricity is that it needs to be used as it’s being generated, which means either immediately feeding into the national grid, or being stored in large batteries. While battery technology is constantly improving, these can be costly to maintain, take up a lot of space and aren’t efficient.

For example, if you have solar panels on your roof, but you’re at work during the day, all that energy being generated while the sun’s out isn’t being used, because you’re not there watching TV or turning the lights on. This means the energy needs to be sent to the national grid, which, while it can earn you money back, typically won’t make up the value you could save on energy if you were using it yourself. The problem is, homes don’t have the batteries required to store this energy being produced.

How do green energy providers work?

Energy providers offering green energy tariffs promise to supply energy that’s up to 100% renewable. This energy comes from a range of sources, including wind farms, solar panels and power stations specialising in biofuels.

If you’re curious as to how much of your energy supply is green, you can look at your supplier’s fuel mix. You can find this on your bill, and it shows a breakdown of how much of your energy supply comes from renewable sources.

No matter who your supply comes from though, your electricity still comes from the national grid, just like everyone else’s. However, a green tariff will mean that more green energy is being supplied to the grid, to make up for your demand.

More and more providers are beginning to offer some form of green energy tariff. When comparing energy quotes with us, simply fill in a few details, including your postcode, energy requirements and email address. We’ll then email you a list of tariffs.

Can businesses have access to green energy?

Yes, like domestic energy, there are green energy options available to businesses. Of course, businesses tend to use much more energy than you would at home, so exploring greener options can make a big difference.

Find out more about business energy here.

Are green energy tariffs more expensive? 

As the demand rises, green-energy tariffs have grown increasingly competitive. Four of the top five cheapest energy tariffs available in September 2020 were for green energy, with all four on average around £300 cheaper than the existing energy price cap. In fact, half of the 30 cheapest tariffs in September 2020 were green.

Compare energy suppliers with Compare the Market today, to find a tariff that’s right for you.

Can I generate my own renewable energy?  

Depending on space and subject to building permissions, you could generate your own renewable power using solar panels, or by investing in a home wind-turbine.

Solar panels are easy to install and don’t need much maintenance, making them the ideal low-impact solution for homeowners and businesses. While solar panels aren’t cheap, they may help you save money in the long run, cutting your energy bills and reducing your dependence on the National Grid.

Installing a wind turbine is a bigger commitment. Not only are they more expensive to install, but you’ll need a lot more space and extra money for ongoing maintenance. However, wind turbines generate more electricity, with a single turbine capable of generating enough power to supply multiple homes.

Can I make money by generating my own energy? 

The government’s Feed-in-tariff scheme allowed households and businesses to earn money back on the energy they generated, as well as selling any excess energy, feeding it into the National Grid. The Feed-in tariff scheme is now closed to new applicants, with some exceptions.

The Smart Export Guarantee, introduced on 1 January 2020, works in a similar way. It can offer payments to people who are generating their own energy through solar, wind, water, micro-combined heat and power or anaerobic digestion. The latter is a type of bioenergy that turns plant material into gas.

What else can I do to be greener?

Switching to a green-energy tariff is one of the best ways to start being greener, but it’s also about reducing the amount of energy you’re using. If you’re looking for ways to save energy and reduce your carbon footprint, take a look at our energy-saving tips guide.

Finding a renewable energy provider  

It’s always a good idea to shop around when searching for the right energy provider. Comparing prices and types of tariff, including those from green-energy sources, is the best way to help you find a supplier that’s right for you.

Switching energy providers is easy to do, with a seamless transition period, so you shouldn’t have a gap in your energy supply.

Start comparing cheaper energy tariffs with Compare the Market today.

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