To effectively address global climate change, the world needs to transform its energy systems from a dependence on fossil fuels (which emit carbon dioxide and other greenhouse gases) to low-carbon energy sources.1 This process of transitioning from carbon-intensive fossil fuels to low-carbon sources is referred to as ‘decarbonisation’.
To achieve this, we have a range of low-carbon energy options. These can be defined within two main categories: renewable technologies (this is inclusive of hydropower, biomass, wind, solar, geothermal and marine sources), and nuclear energy. Both of these options produce very low CO2 emissions per unit of energy compared with fossil fuels.
If we want to reduce our CO2 emissions from energy production, we have to decrease the share of energy we produce from fossil fuels, and increase the share from renewables and/or nuclear energy. So how is the world actually performing when it comes to increasing its share of low-carbon technologies?
In the graph below we see trends in electricity production2 from renewable technologies (hydropower, biomass, wind, solar, geothermal and marine sources, without nuclear) and nuclear energy from 1990-2014. These figures are given as the percentage contribution to total global electricity production. In 2014, renewables accounted for approximately 22% of global electricity, and nuclear about half that at 10-11%.3
What we see from 2005 onwards is a distinct divergence in renewable and nuclear trends (they are essentially a mirror image of one another). Renewable energy’s share has increased by 4-5%, meanwhile, nuclear energy’s share has decreased by approximately the same (4-5%). Our share of ‘low-carbon’ electricity has remained unchanged. We have simply substituted one low-carbon energy source (renewables) for another (nuclear energy).
What we don’t produce from renewables or nuclear is, of course, produced from fossil fuels. In the chart below we have plotted the share of electricity production from fossil fuels (coal, oil and gas), and our combined low-carbon (nuclear plus renewables) sources from 1990-2014. We see that despite an increase in renewable energy production, the share of electricity production from fossil fuels has remained almost completely flat (or even increased marginally) over the last decade. It still represents 66-67% of electricity production.
Whilst the world is making progress in the uptake of renewable technologies, it appears our growing aversion to nuclear has been offsetting progress in decarbonising our electricity grids.