September 12, 2023
Energy Transition
Since the dawn of the Industrial Revolution, our energy needs have been primarily met by the combustion of fossil-derived, non-renewable fuels. Besides a couple of brief intermissions (e.g., the two world wars), society has advanced at a dizzying pace thanks to the conveniences afforded by conventional coal and petroleum-derived fuels. While we are still very reliant on these globally, a transition is also occurring, towards low-carbon, renewable sources of energy. Much of the ‘fuel’ for this transition comes from the urgent need to cut carbon emissions to the atmosphere and mitigate the harmful effects of a warming planet.
The evidence for a warming planet exists in the form of temperature measurements taken as differences between observed temperature and long-term average temperatures during the pre-industrial period (typically, 1850-1900, unless otherwise specified) for multiple locations across the world; an example is shown in Figure 1.
An increase in global average temperature of 1.5 C is recognized as having the potential to contribute to uncertainties in precipitation, extreme droughts, frequency and intensity of temperature extremes, risks to energy, food, and water systems, the occurrence of flash flooding, and the risk of species loss. Mitigating this trend to an increase of 1.5 (or 2.0 °C), per the goals of the Paris Agreement is going to lessen these impacts, although severe risks still persist.
Looking at the source of emissions (2016 data), the vast majority (over 73%) is driven by energy, with other sectors such as agriculture and forestry, industry, etc., contributing the remainder (Figure 2). Industrial energy usage drives the majority of greenhouse gas emissions, followed by buildings (residential and commercial), and transportation. This information points to a strong incentive towards decarbonizing the industrial sector.
Primary energy refers to the original form of energy used in statistical accounting prior to its transformation into a secondary or tertiary energy source. For example, if solar energy was used to generate electricity which was then used to charge an electric vehicle, then solar would be the primary energy source, whereas electricity would be the secondary source of energy. Figure 3 shows the trend of primary energy consumption from different sources of energy for electricity generation between 1971 and 2019. While global demand is still primarily met by coal, natural gas and renewables have been trending towards a greater share of the energy mix. The ‘renewables’ category includes hydroelectricity, solar, wind, biomass, and geothermal energy, etc.
Additionally, sources of energy such as natural gas and renewables have lower emissions as compared to traditional sources such as coal, petroleum, etc., which makes their adoption attractive for emissions reduction.
Where does current energy demand come from?
Looking at the sectors that account for current fossil fuel (coal and oil) usage, heavy industry was one of the largest consumers of coal (Figure 4), followed by sectors such as residential. Coal usage by the iron and steel industry has increased over time. Oil consumption (Figure 5) is primarily driven by road transportation, a share that has been increasing over time.
Finding alternatives to supplement these sector-wide consumption of non-renewable energy sources to mitigate carbon emissions will require a combination of renewable energy sources, such as solar, wind, biomass, and biofuels. Some energy sources (such as solar) lend better to sectors such as residential energy, whereas biomass-based sustainable aviation fuel (SAF) can be a better supplement for aviation energy needs.
References
- NOAA National Centers for Environmental Information, Monthly Global Climate Report for Annual 2022, published online January 2023, retrieved on September 12, 2023 from https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202213.
- IEA, World electricity generation mix by fuel, 1971-2019, IEA, Paris https://www.iea.org/data-and-statistics/charts/world-electricity-generation-mix-by-fuel-1971-2019, IEA. Licence: CC BY 4.0
- IEA, Coal total final consumption by sector, 1971-2019, IEA, Paris https://www.iea.org/data-and-statistics/charts/coal-total-final-consumption-by-sector-1971-2019, IEA. Licence: CC BY 4.0
- IEA, Oil total final consumption by sector, 1971-2019, IEA, Paris https://www.iea.org/data-and-statistics/charts/oil-total-final-consumption-by-sector-1971-2019, IEA. Licence: CC BY 4.0
- Hannah Ritchie, Max Roser and Pablo Rosado (2020) – “CO₂ and Greenhouse Gas Emissions”. Published online at OurWorldInData.org. Retrieved from: ‘https://ourworldindata.org/co2-and-greenhouse-gas-emissions’ [Online Resource]