How green is your electricity tariff?

One way you can reduce your impact on the environment is to buy energy from a renewable or low-carbon source.

Green electricity is now a popular choice 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 to a renewable electricity tariff. But in practice, it’s a bit more complicated than that.

Let's get into the detail

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 to do with 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 if they're not?

So this is how it works: for every 1000 units of renewable energy generated, Ofgem hand 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 at the same time, for around 15p per certificate. Every year the suppliers must send their REGOs to Ofgem. 

However, the market for these certificates is separate to the market for power. Therefore, suppliers can buy as many REGOs as they like 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 was 100% green, when in fact, it wasn’t.

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

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

How do I ensure I’m using 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 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, our Powervault 3 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.

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 sources of energy 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 demand for electricity.

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