By 2050, primary consumption could rise to slightly over 1,000 EJ if it continues growing at the same rate, a total increase of 75% compared with 2019.
Population growth, urbanisation, rising incomes, and the enormous unmet demand for energy services will all boost energy consumption over the next three decades, especially in fast-growing developing economies.
Offsetting these drivers there is scope for increased efficiency, but over the last five decades, efficiency gains have nowhere fully offset rising energy demand, except in the wealthiest countries.
Given uncertainties about population growth, urbanisation, incomes and efficiency improvements, there is considerable uncertainty about the resulting rise in total energy consumption.
But if energy consumption increases by between 1.2% per year (one-third slower than over the last three decades) and 2.4% per year (one-third faster), consumption will climb between 842 and 1,212 EJ by the middle of the century.
In 2020, zero-emission energy sources (nuclear, hydro, wind, solar and other renewables) supplied 94 EJ of primary energy, just 16% of global energy consumption, according to BP data.
To meet the ambition of net zero emissions while simultaneously satisfying growing demand for energy services, production from zero-emission sources would have to be scaled up 9-13 times in 30 years.
Hydro and nuclear power production are unlikely to increase by anything like this amount, implying the need for even faster growth in wind, solar and other renewables.
The problem becomes more tractable if coal, oil and gas remain a significant part of the energy mix by coupling them with carbon capture and storage technology or other ways to offset their emissions.
Even so, the implied deployment of zero-emissions energy technologies will be exceptionally difficult and may be impossible within the time frame policymakers have set for themselves.
MODERN ENERGY SERVICES
In addition to the net zero target, global policymakers have committed themselves to ensuring universal access to affordable, reliable and modern energy services, as part of the United Nations Sustainable Development Goals.
Across much of sub-Saharan Africa, as well as parts of Asia and Latin America, even the most basic energy needs for cooking and heating have still not been met.
Progress towards providing universal household access to electricity and clean cooking fuels remains far off track to meet the implementation deadline of 2030.
In urban areas, most households now have access to electricity, even in developing countries, but one-fifth of rural households worldwide still lack this basic energy service, according to the World Bank.
More seriously, one-third of the world's population still relies on traditional cooking fuels such as wood, coal and kerosene, according to the World Health Organization.
Household fuel combustion is responsible for significant indoor air pollution, contributes to poor outdoor air quality, and was one the world's leading causes of mortality before the coronavirus epidemic.
The World Health Organization estimates household air pollution was responsible for almost 4 million deaths in 2016 ("Household air pollution and health", WHO, 2018).
Use of solid fuels and kerosene is associated with increased mortality from acute lower respiratory disease, chronic obstructive pulmonary disease, stroke, coronary heart disease, and lung cancer.
The Sustainable Development Goals envisaged polluting cooking fuels being replaced with electricity, natural gas, liquefied petroleum gas, biogas, ethanol and solar, but around 3 billion people still rely on them.
ADVANCED ENERGY NEEDS
Beyond satisfying basic needs, over time households in developing countries are likely to want to use more advanced energy services for lighting, heating, air-conditioning, television, computing and transport, including aviation.
In 2019, the average person in the advanced economies in the Organization for Economic Cooperation and Development used more than three times as much energy as their counterparts in the rest of the world.
But developing countries have been steadily closing the energy consumption gap, which has narrowed from 7:1 in 1969 and 6:1 in 1979 to 5:1 in 1989 and 4:1 in 2009.
If developing countries continue to close even part of the gap, the increase in primary energy use will be enormous.
Rising living standards and energy consumption in developing countries explain why most projections show big increases in global energy demand by 2050, even if energy efficiency can be improved.
Policymakers often describe the transition to a future energy system as characterised by two revolutionary changes: electrification of the overall energy system and the decarbonisation of electrical networks.
But there is a third transformation, providing basic and advanced energy services to developing countries, based on zero-emission sources, which is likely to be even more challenging.
(John Kemp is a Reuters market analyst. The views expressed are his own)
(Editing by David Evans) ((firstname.lastname@example.org))