Today when we think about energy sources, a diverse mix comes to mind – coal, oil, gas, nuclear, hydropower, solar, wind, and biofuels. But a diverse energy system is a very recent phenomenon. Go back a couple of centuries and we see that we relied on only one or two key sources of energy.
In the chart we see global primary energy consumption dating back to the year 1800.1
Until the mid-19th century, traditional biomass – the burning of solid fuels such as wood, crop waste, or charcoal – was the dominant source of energy used across the world. With the Industrial Revolution came the staggering rise of coal. By the turn of the 20th century, around half of the world’s energy came from coal; and half still came from biomass.
Throughout the 1900s, the world adopted a broader range of sources. First oil, gas, then hydropower. It wasn’t until the 1960s that nuclear energy was added to the mix. What are often referred to as ‘modern renewables’ – solar and wind – were only added much later, in the 1980s.What stands out from this 200-year history of global energy use is that energy transitions have been very slow in the past. It has taken many decades – or even a century – for a particular energy source to become dominant. While this is true of the past, there are signs that this is changing. Some recent energy transitions happened very quickly. In the UK, for example, nearly two-thirds of electricity came from coal power in 1990. By 2010, this had fallen to just below one-third. And in the decade that followed it fell to around 1%.
Historical energy transitions have been slow; but future transitions do not have to be.