Global electricity efficiency has remained stagnant at 15-17% since 1960, according to a recent study that produced a comprehensive global electricity dataset from 1900 to 2017. The dataset also highlighted a significant rise in efficiency from 2% to 15% between 1900 and 1960.

Structural transitions and end-use changes have caused this stagnation, such as the increasing share of low-temperature heating and the decreasing importance of static mechanical work. The study emphasizes that technological developments alone will not be sufficient to change aggregate electricity efficiency, but rather the mix of end-uses will have a significant impact. This underscores the need for a deeper investigation of the full impact of electrification on world energy efficiency and highlights the unprecedented challenge of meeting Paris targets through both the electrification of end-uses and the transition to renewables at sufficient speed.

Here’s the stats heavy breakdown:

Research Rationale:

The paper aims to investigate the historical trends in global electricity efficiency from 1900 to 2017, and the factors that contributed to its rise and stall. The authors argue that understanding the past trends of electricity efficiency is essential for the transition to renewable energy sources, as efficient energy use is critical to reducing greenhouse gas emissions and mitigating climate change.

Methodology:

To achieve this goal, the authors use a dataset of national electricity consumption and generation, population, and GDP from 1900 to 2017. They calculate the energy intensity of electricity generation and the energy efficiency of electricity use using a modified version of the Kaya identity. (The Kaya Identity Method is a mathematical formula that helps estimate the factors that contribute to carbon dioxide emissions).

Findings:

The authors find that the global electricity intensity (electricity generation per unit of GDP) has decreased from 7.1 kWh per dollar in 1900 to 0.8 kWh per dollar in 2017. However, the global electricity efficiency (electricity generation per unit of electricity consumption) has stalled since the 1980s, hovering around 40%.

Historical perspective:

• Between 1900 and 1950, over 95% of the world’s electricity was produced from coal and hydro sources, with coal representing 55% and hydro 40%.
• During this period, primary-to-final exergy efficiency increased significantly from 6% to 31% due to efficiency improvements in thermal power plants.
• The industrial sector increased its share of electricity consumption at the expense of the transport sector, with iron and steel decreasing its share more than 10%.
• Final-to-useful exergy efficiency increased only slightly from 1900 to 1950 from 44% to 47%, due to efficiency dilution effects. Primary-to-useful exergy efficiency, the product of both efficiencies, increased sharply.
• Carbon intensity decreased to 0.85 kgCO2/kWh (CIF) and 2.13 kgCO2/kWh (CIU) respectively by 1950, less than 1/5th of their 1900 values, mainly because of primary-to-final efficiency improvements. Nonetheless, CO2 emissions increased 24-fold during this period due to the near 150-fold increase in electricity production.
• In the second period (1950-2017), electricity production from nuclear, oil, and natural gas sources rose in prominence. The last decade saw an increase in the combined share of solar and wind, which remains less than 10%.
• Throughout 1950-2017, residential and commercial sectors increased their shares of electricity consumption, at the expense of the industrial sector. The share of the machine tools and pumps end-uses decreased sharply due to the decrease in the share of the industrial sector.
• Final-to-useful exergy efficiency remained overall stable at between 46% and 50%, due to efficiency dilution effects. Primary-to-useful exergy efficiency increased until 1960, caused by the increase in primary-to-final exergy efficiency, and stabilized afterwards.
• In 2017, carbon intensity was almost half the 1950 value. CIF declined continuously until 1985. The decline in CIF between 1950 and 1970 is due to growing primary-to-final efficiency, while from 1971 to 1985, carbon intensity improvements are explained by an increase in the share of electricity production with no CO2 emissions, mostly nuclear power.
• Although carbon intensity stabilized between 1985 and 2014, electricity production more than doubled, and therefore total electricity-based CO2 emissions also more than doubled. The most recent decline in carbon intensity (2014-2017) is caused by growth in wind and solar electricity.

Electricity efficiency:

• End-use efficiency is assumed to be a key driver of energy reductions and carbon emissions in future scenarios.
• Individual exergy efficiencies grew from 1900-2017 due to technological evolution, but aggregate primary-to-useful exergy efficiency gains were significant only until mid-1930s.
• There is no obvious correlation between aggregate primary-to-useful exergy efficiency, electricity consumption, and CO2 emissions.
• Final-to-useful exergy efficiency increased slightly from 44% (1900) to 47% (2017) due to efficiency dilution caused by growing demand for less efficient end-uses.
• This is the first study to estimate world electricity production and consumption efficiency over a long period.
• Global electricity consumption is expected to rise from 19% in 2022 to over 40% by 2050.
• Electrification may contribute to an increase in aggregate final-to-useful exergy efficiency, as electricity end-uses typically have higher efficiency compared to other end-uses.

Energy Transition:

• World electricity production and consumption time series can provide insight into future energy transitions towards decarbonization.
• Electrification of end-uses will create structural changes to electricity consumption, with an increase in the share of electricity consumption for the transport sector expected to reach over 20% of total electricity consumption by 2050.
• Aggregate world final-to-useful exergy efficiency is expected to increase due to the transport sector remaining more efficient than the commercial and residential sectors.
• IEA forecasts predict that electricity production will double between 2020 and 2050, and past increases suggest this scenario is feasible.
• A transition to electricity by 2050 and electrifying all end-uses currently using fossil fuels could reduce final energy demand by more than 50%.
• Efficiency alone has never been sufficient to decrease CO2 emissions, and electrification and efficiency must be linked with a deep renewables transition for decarbonization to occur.
• The transition to renewables must happen quickly (10-20 years) to meet Paris climate objectives, but historical transitions have been slow and too small to reduce electricity-related CO2 emissions, which have increased almost every year.
• Carbon intensity of electricity production is an insufficient metric to assess transitions if the goal is reducing CO2 emissions.
• In 2017, carbon intensity of electricity production was 0.49 kgCO2/kWh, and a reduction to 0.10 kgCO2/kWh is required by 2050 according to the IRENA scenario, which implies a further reduction of 0.39 kgCO2/kWh in less than 40 years.
• The necessary speed of decrease of carbon intensity to meet Paris objectives is unprecedented, as rising demand for electricity has always outstripped the capability of efficiency to reduce CO2 emissions.

Final words: Both the electrification of end-uses and the transition to renewables are required to meet Paris targets, which will be unprecedented in speed and scope.

Paper Title: The rise and stall of world electricity efficiency:1900–2017, results and insights for the renewables transition

Authors:
Ricardo Pinto a,*, Sofia T. Henriques b,c, Paul E. Brockway d, Matthew Kuperus Heun e,
Tˆania Sousa a

a MARETEC—Marine, Environment and Technology Center, LARSyS, Instituto Superior T ́ecnico, Universidade de Lisboa, Avenida Rovisco Pais, 1, Lisboa, 1049-001,
Portugal
b CEFUP, Faculdade de Economia da Universidade Do Porto, Rua Dr. Roberto Frias, 4200-464, Porto, Portugal
c Department of Economic History, Lund University, Box 7080, S-220 07, LUND, Sweden
d Sustainability Research Institute, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
e Engineering Department, Calvin University, 3201 Burton St. SE, Grand Rapids, MI 49546, USA

The full paper is under the Creative Commons License and is available here.