Lowered energy demand reduces pressure on scarce natural resources, reducing the need to explore increasingly challenging locations for extraction. GHG emissions reduced through energy efficiency include both direct emissions reductions from fossil fuel savings and indirect emissions reductions in the power sector from the electricity savings. Reducing energy consumption and emissions through energy efficiency also plays a role in reducing air pollution, which leads to health improvements as well as reduced waste and the associated pollution of land and water, thereby contributing to efforts to combat ocean acidification and limit negative impacts on biodiversity.
One way to mitigate the impact of the growth in the demand for materials on energy demand is to improve material efficiency – delivering the same material service with less overall production of materials. Promoting a higher degree of efficiency in the value chain of production and in the use phase, while making sure that the same service is delivered to the consumer, can take several different forms: reducing the weight of products while delivering the same service (light-weighting); reducing yield losses in the manufacturing process; finding alternative uses for scrap without re-melting; re-using and recycling components; creating longer-lasting product components; and using products more intensely or at a higher capacity (Cullen et al, 2012).
Reducing the demand for energy-intensive materials and product recycling lowers energy demand. Typical final energy savings from recycling are up to 90% for aluminium, around 75% for steel and around 80% for plastics. Improving the efficiency of materials use is not new: fabrication yields are continuously improving, global recycling rates are increasing and products are consistently being light-weighted.
Promoting higher degrees of energy efficiency and material efficiency are related, as both promote a higher degree of efficiency along the value chain of production. The difference between energy efficiency and material efficiency is the production input. Material efficiency, in most cases, is complementary to energy efficiency, but the two reinforce each other. A car that contains less steel not only avoids the energy associated with excess steel production but also weighs less, leading to increased fuel efficiency during use. On the other hand, trade-offs also exist between energy and material efficiency: for example, extending the lifetime of steel-containing appliances means that the adoption of more efficient devices by consumers will occur later.
After decades of consecutive increases, GHG emissions from fossil fuel combustion have been steady at around 32 billion tonnes of carbon-dioxide equivalent (GtCO2-eq) since 2014. This is due to a combination of the decline in energy intensity and the change in the energy mix towards natural gas and renewable energy. The changing fuel mix offset 23% of the impact on global emissions from GDP growth since 2014, while falling energy intensity offset 77%, affirming the vital role of energy efficiency in steadying and reducing emissions.
Figure 1. Global fuel-combustion related GHGs since 1990 (left) and an analysis of the factors that influence GHGs, 2014-16 (right)
Source: IEA, Energy Efficiency 2017
Note: Energy intensity is calculated as Total Primary Energy Supply per thousand USD of GDP in 2016 prices at PPP.
Global energy savings from energy efficiency improvements since 2000 led to a reduction in GHG emissions of just over 4 billion tonnes of carbon dioxide equivalent (GtCO2-eq) in 2016. Without these energy efficiency improvements, emissions in 2016 would have been 12.5% higher. Of these emissions reductions, 45% came from IEA member countries, while major emerging economies accounted for 47%. The avoidance of fuel combustion that results from energy efficiency improvements also reduces local air pollutants, benefiting air quality and public health.
Figure 2. Avoided global GHG emissions from energy efficiency improvements, 2000-16
Source: IEA, Energy Efficiency 2017
Note: Energy savings for countries other than IEA members and the major emerging economies are estimated by applying the ratio of efficiency improvements to intensity gains observed in emerging economies to the gains in intensity observed in these other countries.