Feature Report: The Energy Mix and Energy Transition

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The Challenges of the Energy Transition

Most countries in the world have embarked on an “energy transition” – or are thinking about doing so – under the dual influence of the realization that fossil fuels are a limited resource, however long supplies might last, and, more recently, the growing awareness that they are adversely impacting the planet’s climate. But what does an energy transition actually entail?

Wind turbines in Rio Vista, California: renewable energies are expanding worldwide. © FOTOLIA

The term energy transition refers to the shift from current energy production and consumption systems, which rely primarily on non-renewable energyNon-renewable energy or fossil fuels are forms of primary energy that cannot be replenished after use on a human time scale... sources such as oil, natural gas and coalCoal is ranked by its degree of transformation or maturity, increasing in carbon content from..., to a more efficient, lower-carbon energy mixThe range of energy sources of a region.. This type of transition is not without precedent. The energy mix has been transformed in the past, first by the introduction of coal in the mid-19th century and then by oil in the mid-20th century and nuclear powerIn physics, power is the amount of energy supplied by a system per unit time. In simpler terms, power can be viewed as energy output... in the 1970s — although these new forms of energy added to, rather than replaced, existing sources.

No Ideal Universal Energy Mix

Most experts agree on a number of points:

  • There is no single mix that would be ideal worldwide. Although major international climate summits seek to adopt global objectives, the energy transition is specific to each country or group of countries.
  • Energy systems are not very dynamic, meaning that an energy transition is a slow process.
  • Energy transitions required technological breakthroughs and radical changes in energy use by consumers (See Close-Up "Technological Breakthroughs and New Energy Uses").

No single mix would be ideal worldwide. The energy transition will be different in each country. 

The “Energy Trilemma”

The World Energy Council, an alliance of leaders and practitioners from close to 100 countries, has summed up the challenges in their “energy trilemma” concept, which involves balancing three seemingly conflicting yet interwoven objectives:

64%, the share of fossil fuels in the 2035 world energy mix according to the IEA’s 2°C  scenario.

International Energy Agency (IEA) Scenarios

Experts at the IEAAn independent, intergovernmental organization founded within the framework of the OECD... have developed scenarios assessing the impact of changes in the global energy mix on global warming, drawing on the findings of the Intergovernmental Panel on Climate Change (intergovernmental panel on climate change (ipcc)Body established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988...).

In 2015, in its annual World Energy Outlook (WEO)1, the IEA unveiled a scenario aimed at achieving the target first set at the Copenhagen Climate Summit and later confirmed in the December 2015 Paris Climate AgreementOil contract under which the oil that is produced is shared between the state and the oil company..., that is, an increase of less than 2°C in the average global temperature by the end of the century compared with pre-industrial levels. 

Updated in the WEO-2016, the 2°C scenario assumes a sharp drop in the carbon content of global growth, as measured by world gross domestic product (GDP). Improving “carbon intensity”, or the ratioIn mathematics, the relationship between two numbers (the ratio of x to y is equal to x/y). Often expressed as a percentage... of greenhouse gas emissions to growth in global production, means simultaneously optimizing the current energy mix, developing renewable energies and improving energy efficiency.

The improvement of the prevailing energy mix implies increasing the share of natural gas relative to coal and oil. This is because, for equivalent energy content, gas emits half the amount of CO2See Carbon Dioxid as coal in power generation. The IEA’s 2°C scenario also factors in the ramp-up of carbon capture, utilization and storage (CCUS) technologies. The development of renewable energies will require greater use of solar, wind and biomassIn the energy sector, biomass is defined as all organic matter of plant or animal origin.... And the IEA foresees increased energy efficiency through continuous improvements in industrial processes, housing and transportation.

In the 2°C scenario, coal is expected to account for 16% of the global energy mix in 2035 (versus 25% in 1990), oil 25% (versus 37%) and gas 23% (versus 19%). This means fossil fuels will account for a total of 64% of the world’s energy mix (versus 81% in 1990). Nuclear power is projected to rise from 6% of the mix in 1990 to 10% in 2035, hydropower from 2% to 4%, biomass and biofuelA fuel produced from plant or animal matter. There are currently two types of biofuel... from 10% to 14%, and other renewables from 0% to 9% (See Infographic "Global energy mix from 1990 to 2035").


“The Stone Age did not end for lack of stone, and the Oil Age will end long before the world runs out of oil.” This now famous adage was spoken by Sheikh Yamani, former Saudi oil minister, in an interview with The Daily Telegraph on June 25, 2000. 



(1) World Energy Outlook 2015