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How green is your energy tariff?

By Marta Moses | Posted January 29, 2020

The British public is on board to reduce our country's carbon emissions to zero by 2050. Many of us now choosing green energy, with more than half of UK electricity tariffs claiming to provide renewable power.

It’s easy to assume that you're using 100% renewable electricity 100% of the time when you sign up for a green electricity tariff. But in practice, it’s a bit more complicated than that. 

Let's get into the detail of what green energy really is

Even when your tariff promises 100% renewable energy, there are times that gas and coal power are keeping the lights on. But why?

It’s all about how power gets from energy generators such as power stations and wind farms to homes across the UK. The National Grid doesn’t separate renewable and non-renewable energy, so the electricity arriving at our homes comes from a mix of sources generated all across the UK.

How can energy companies say they're green?

So this is how it works: for every 1000 units of renewable energy generated, Ofgem hands over one green certificate. This green certificate is called a Renewable Energy Guarantee of Origin (REGO for short).

When an energy supplier buys this renewable power from the generator (to sell on to customers), it buys REGOs simultaneously for around 15p per certificate. Every year, the energy suppliers must send their REGOs to Ofgem. 

However, the market for these certificates is separate from the market for power. Therefore, suppliers can buy as many REGOs as they like at a low cost without actually buying any power from that renewable generator. 

So, where do they buy their power from? This is the confusing part. They can buy power from anywhere. So long as they have enough bought REGOs to match. The supplier can then show the REGOs and legally claim their energy usage is 100% green when, in fact, it wasn’t.

Look behind your energy supplier’s green tariff, and you’ll unlikely find they exclusively buy or generate electricity from renewable sources. 

Take a look at this Which? article to discover more about this. 

How can we meet our Net Zero target then? 

Renewable energy is great, and it's growing, but it's not always reliable. This is where we come in. We're Britain's largest generator of zero-carbon electricity(1), and all our home fixed tariffs get zero-carbon electricity as standard(2).

So, we actually produce our clean electricity, and we don't need to buy certificates, which some see as energy greenwashing

If more of us switch our energy providers to those that supply their own generated renewable or zero-carbon electricity, we can be on our way to meeting our Net Zero target. 

Is there any way to use only renewable electricity?

The only way to guarantee you’re using renewable electricity 100% of the time is to generate your own. 

For example, by installing photovoltaic (PV) solar panels. Simple, durable and effective, solar panels turn the sun’s energy directly into electricity. This can be consumed as it’s produced or fed back into the grid to power other homes and businesses.

In recent years, improving solar battery technology has given homeowners with solar panels a way to store the electricity they generate rather than feed all the excess energy back into the grid.

For example, solar battery technology helps homeowners make the most of the renewable electricity they generate – and it can optionally be used by your electricity supplier to store and supply electricity for the grid, helping balance out renewable generation with peak demand.

However, it's very hard to go completely 'off-grid', so you might want to back up your own generation with a tariff that you know is backed by zero carbon electricity generation, just as our fixed tariffs are. 

The takeaway? When choosing an electricity supplier, always look behind their renewable tariffs to see just how green the energy really is.

Our commitment to renewable energy

We’re working hard to build and invest in as many renewable energy sources as possible for the UK.

We currently operate 36 wind farms and have many more renewable projects in planning and development. We’re also the proud owners of one of the largest battery storage units in Europe – a way in which we’re helping balance the variable output from wind generation against the electricity demand.

As a leading provider of renewable electricity, we're committed to providing reliable, low-carbon and affordable energy to the UK – and working to support customers who want to generate and store their own.

Discover all our renewable energy projects