Energy efficiency has tremendous potential to boost economic growth and avoid greenhouse gas emissions, but the global rate of progress is slowing, according to a new report by the International Energy Agency.

Global primary energy demand rose by 2.3% in 2018, driven in large part by the People’s Republic of China, India and the United States, which were responsible for 70% of demand growth. In the United States, primary demand increased for the first time since 2014.

Primary energy intensity—an indicator of how much energy is used by the global economy—improved by just 1.2% in 2018—the slowest rate since 2010—according to Energy Efficiency 2019, the IEA’s annual report on energy efficiency.

This was slower than the 1.7% improvement in 2017 and marked the third year in a row the rate has declined. It was also well below the average 3% improvement that would be consistent with the IEA Efficient World Strategy.

Primary intensity improvements varied by region, according to the report. In China and India, primary intensity improved by almost 3%, a slight drop on 2017 levels. In Europe, it improved by 2%, up from 1.4% in 2017. In the United States, primary intensity worsened for the first time in more than 25 years.

In 2018 final demand (total final consumption) grew by 2.2%, continuing an increasing trend since 2015, driven by strong growth in energy-intensive industries.

Of the increase in final demand in 2018, growth was strongest in gas (5.7%) and electricity (4.1%). Gas demand growth was driven by its use in industry and buildings for heating. China continued to implement policies designed to shift households and businesses from coal to gas boilers, mainly for air quality reasons. Electricity demand growth came mostly from the buildings sector as more people gained access to modern energy services and exceptional weather drove demand for heating and cooling.

Oil represented the largest share of final demand, at around 41%, but demand growth slowed to 1.5% in 2018, a trend that has continued since 2015 when demand grew by 2.5%. In 2018, higher oil prices helped dampen demand for road transport fuels.

In 2018, demand for coal continued to decline (by 3.5%), partly due to switches from coal to gas, noted above, although since 2016, the annual rate of decline has slowed.

Transport. In the transport and residential buildings sectors, structural factors are reducing the impact of technical efficiency improvements, the report found. In both these sectors, technical efficiency gains have been smaller than in the industry and services sector but are still improving at or above the five-year average.

Since 2015, annual technical efficiency gains in the transport sector averaged over 1% of final transport energy demand. However, this gain has been offset primarily by users’ purchasing decisions and behavior.