Q3 2020: The low carbon electricity league table

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by Dr Iain Staffell – Imperial College London 

A lot can change in a decade.  

Around the world, coal is being pushed out of major power systems by renewables, but who has been successful at decarbonising their electricity?  We rank the world’s 30 largest electricity systems by the carbon content of their generation mix, and explore the changes that occurred over the last ten years.  We find that the UK has decarbonised its electricity system at almost twice the pace of any other major economy by growing renewables six-fold and slashing the use of coal.

The carbon intensity of electricity generation in the world’s thirty largest markets at the start and end of the last decade [left] and the change in electricity carbon intensity in the world’s thirty largest markets over the last decade [right]

There is a huge variation in how much carbon is emitted when generating one kWh of electricity around the world.  It ranges from just 13 grams of CO2 in Norway up to 880 grams in South Africa.

The cleanest countries at the top of the league table – Scandinavia, France, Brazil and Canada – all have large hydropower resources or a sizeable share of nuclear power.

Not everywhere has the same natural resources or historic infrastructure, so it matters how fast emissions are falling.  The red bars in the chart to the left show the change in emissions intensity between 2010 and 2019.

Of the thirty largest electricity consumers (all over 100 TWh per year), the UK has decarbonised faster than anywhere else over the last decade.  The UK’s carbon intensity fell from 450 to 195 g/kWh, a fall of 58%.  British households are emitting three quarters of a tonne of CO2 less per year just from changes in the power system alone.1  

This is double the reduction seen in the other major economies.  Great progress has also been made in the USA, Germany, Australia and China, where carbon intensities have fallen by 120–150 g/kWh over the past decade.

These are not the places that many would associate with world-leading shifts towards clean energy – as the soundbites of China building a coal power station every week, or ”Trump digs coal” live long in the memory.  But, these countries embody the two big macro trends going on in electricity generation: the shrinking role for coal, and growing share of renewables.

The chart below highlights the changes seen in these two areas. The countries which have done most to clean up their electricity generation sit in the top left.  Across the five highlighted countries, their electricity mix has shifted from around two-thirds to one-half coming from coal over this period (a 15 percentage points fall), and their share of renewables doubled from an eighth to a quarter (12 percentage points gain).  The UK stands out in front, with coal falling from 30% to just 2%, and renewables increase from 8% to 42%.

It is crucial that the coming decade sees most countries follow this path.  It is five years since the Paris Agreement was adopted by almost 200 countries, and while much has improved since then, global carbon emissions have continued to rise.  Power systems provide one of the cheapest and most effective ways to reverse this trend, and the UK offers the world an example of how fast the transition can be made.

Evolving electricity mixes used around the world,2 showing the change in the shares of coal and renewables between 2010 and 2019

[1] A typical house consuming 2,900 kWh per year would save 777 kgCO2 per year.  Houses with electric heating would typically save more than a tonne (1125 kg) of CO2 per year, based on average consumption of 4,200 kWh per year.

[2] Geographic regions shown are those recognised by the United Nations Statistical Commission.

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