Global Transitions Indicators

Tracking energy transitions

Tracking global energy transitions

Global energy-related CO2 emissions increased again in 2018, indicating a clear lack of progress in the global clean energy transition. This page explores trends in key energy transition indicators to unpack the underlying drivers of change in energy supply intensity and end-use efficiency that drive energy sector CO2 emissions.

IEA analysis of the latest data shows that only one of the four intermediate clean energy transition indicators – share of electricity in end use – was on track with the progress needed in 2018.

Average annual change in key high level indicators

	2000-2018	Change in 2018	SDS 2018-2040
Energy-related CO2 emissions	2.020195789	1.6853381	-2.767105063
Final energy carbon intensity	0.099492964	-0.260616866	-2.806002298
Electricity mix carbon intensity 	-0.652782029	-1.218417176	-8.409538752
Electricity share in final demand	1.253850536	1.520548439	1.709041188
Energy intensity	-1.604679677	-1.595523076	-3.445520539
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No single indicator can fully capture the complexity of the global clean energy transition. As the energy sector accounts for nearly 90% of CO­2 emissions globally – and is therefore the dominant contributor to climate change – the IEA’s global transition indicators are designed to track the makeup of the energy sector’s CO2 emissions. The indicators build up from underlying sector-specific emissions drivers to intermediate indicators, and ultimately to the energy sector’s total contribution to CO2 emissions.

These global transition indicators can guide short-term action for policy makers seeking to achieve immediate clean energy transition objectives, as well as drive long-term decarbonisation. Tracking the energy sector transition from a broader, sustainable-development viewpoint is also critical, as demonstrated by efforts to track progress towards Sustainable Development Goal (SDG) 7.

Tracking framework

Global energy-related CO2 emissions are the product of economic, technological and demographic factors. The IEA has identified a set of indicators that unpack the main underlying drivers of change in energy supply intensity and end use efficiency that, along with some intermediate indicators, ultimately determine the energy sector’s contribution to CO2 emissions.

These drivers identify key opportunity areas for enhanced action – i.e. they are ‘levers’ that can be pulled to accelerate the transition. Together, the indicators make up an accessible and comprehensive tracking framework that can help inform effective and well-co‑ordinated policy-making. They include cross cutting drivers, such as investment in low-carbon energy supply and end-use. Working from the bottom up, they also incorporate indicators of energy use efficiency and direct fuel use decarbonisation across industry, buildings and transport end use sectors. In parallel, these indicators track power generation decarbonisation and energy integration progress.

Global transition progress

Global energy-related CO2 emissions increased again in 2018, indicating a clear lack of progress in the global clean energy transition.

Analysis of the underlying drivers behind this trend indicates that only one of the four intermediate clean energy transition indicators – share of electricity in end use – was on track with the progress needed in 2018. The other three are significantly off track, showing that the progress in clean energy transition is not sufficient.

Simultaneous progress across all the indicators (electrification, decarbonisation and energy efficiency) – as well as an investment boost – is needed for the clean energy transition to happen at a sufficient pace. Importantly, while electrification has been moving in the right direction, with electricity growing at twice the rate of global energy demand, improvement in carbon intensity of electricity generation has not been sufficient to ensure that additional electricity demand is being met by low-carbon sources.

Energy-related CO2 emissions

Global energy-related CO2 emissions rose by 1.7% in 2018, the second consecutive year of growth after three flat years, reaching a historic high of 33 gigatonnes (Gt).

The increase in emissions was driven by higher energy consumption resulting from a robust global economy as well as from weather conditions in some parts of the world that prompted higher energy demand for heating and cooling. Current and planned policies, including the Nationally Determined Contributions (NDCs), are clearly not ambitious enough to reduce energy-related CO2 ­emissions: the increases of the past two years confirm that we are off track.

Global fuel combustion-related CO2 emissions

Following a brief hiatus, global energy-related CO2 emissions increased for the second consecutive year in 2018. To achieve the goals of the Paris Agreement, however, CO2 emissions need to peak soon and decline steeply after 2020.

	Total	Power	Transport	Industry	Buildings
2000	23.12254899	9.30496653	5.757330139	3.800879653	2.714221333
2001	23.47146496	9.5078247	5.788782784	3.827996477	2.747187674
2002	23.78282661	9.63709876	5.927863204	3.818814129	2.744303525
2003	24.82514854	10.20251083	6.061801968	3.998092898	2.834714993
2004	25.99529161	10.5681569	6.338642644	4.435029403	2.8871447
2005	26.96095127	10.92301855	6.473184126	4.851502703	2.8941626
2006	27.80654419	11.35179098	6.619485384	5.090673515	2.869437109
2007	28.86096499	11.85457995	6.82715492	5.361851789	2.870152265
2008	29.08042175	11.82992001	6.835590435	5.513647064	2.93269288
2009	28.68539567	11.65305332	6.702085503	5.482328547	2.906689888
2010	30.33130251	12.40701045	6.987265405	5.95346864	2.94018384
2011	31.16236365	12.97502735	7.091786215	6.181127731	2.866679689
2012	31.48883439	13.24820617	7.162347348	6.16998119	2.843435209
2013	32.10265377	13.48634253	7.358231685	6.201053537	2.954942257
2014	32.13838726	13.43671145	7.481625205	6.228618591	2.907924198
2015	32.08090364	13.25741648	7.699035601	6.150333381	2.91973441
2016	32.05308108	13.24730734	7.85123826	6.003762859	2.945481672
2017	32.58035787	13.58735764	7.985531305	5.973845824	2.997235671
2018	33.1425909				
2020	32.24612668	12.88853129	8.096102647	6.194035911	2.94750274
2025	29.53513792	10.65645934	7.931631026	6.109310592	2.767166861
2030	25.4815813	7.838544571	7.325545654	5.798619773	2.59346829
2035	20.98192906	5.127261698	6.373226853	5.368779096	2.367205417
2040	17.64690866	3.292261607	5.562692461	4.987285508	2.201672592
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To reach long-term climate change mitigation targets, emissions need to peak around 2020 and decline steeply thereafter – requiring a rapid reversal of the rebound seen during the last two years. The IEA’s SDS shows that energy-related CO2 emissions need to be 47% below the current level by 2040 to be on track with the Paris Agreement. To achieve this, they start falling at an increasing pace reaching 2% annual reduction in 2020s and almost 4% in 2030s.

Final energy carbon intensity

The final energy carbon intensity tracks the amount of global energy-related CO2 emissions (expressed in tonnes of carbon dioxide) per unit of total final consumption (tonnes of oil equivalent), across the whole global energy system. It shows the net impact of policy changes, shifts in investment and technology developments on CO2 emissions in the energy sector and give a measure of how ‘clean’ the global energy mix is from a climate perspective.

Energy sector carbon intensity

In 2018, the world’s energy consumption mix was almost exactly as carbon-intensive as in 2000. Final energy carbon intensity needs to decline by 47% from the current level by 2040 to achieve the SDS.

2000	3.286532759
2001	3.317750939
2002	3.308303938
2003	3.350807095
2004	3.356643807
2005	3.382690556
2006	3.402395912
2007	3.438720442
2008	3.431932155
2009	3.419947954
2010	3.43900023
2011	3.48088583
2012	3.478588579
2013	3.482482178
2014	3.450786137
2015	3.412841207
2016	3.363399129
2017	3.36220793
2018	3.345890803
2020	3.202303891
2025	2.916691888
2030	2.546392365
2035	2.109485541
2040	1.772192653
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Unfortunately, this indicator has changed very little in the last 30 years. It has been on a declining trajectory since a peak in 2013, showing tentative signs that the global energy supply has become somewhat cleaner with greater use of renewables and less coal in recent years, but higher fossil fuel use to meet final energy demand growth has stalled improvement since 2016.

The full spectrum of low-carbon options, including nuclear, is needed to get on track with the SDS carbon intensity reductions of 24% by 2030 and 47% by 2040. It will require progressive increase in annual rate of carbon intensity reduction, from around 2% throughout 2020s to 4% in 2030s.

Decarbonisation of electricity and electrification of energy demand

Electrifying end-use subsectors is an important option for decarbonising the energy sector – if power generation is decarbonised rapidly at the same time. Increasing shares of electricity are being realised in transport (for EVs and freight), in buildings (for cooking, heating and appliances) and in industry, but challenges remain.

The share of electricity reached almost 20% in 2018, having risen incrementally each year from 15% in 2000. It is estimated that electrification is expanding even under current policies (according to the New Policies Scenario [NPS]), but its pace needs to more than double to achieve the SDS potential of 28% in 2040.

Share of electricity in total final energy consumption

The carbon intensity of electricity generation fell 11% during 2000 18, while the electrification share of energy demand rose from 15% to 19%. To reach SDS, carbon intensity has to decrease 86% from 2018 to 2040 and electrification share needs to rise a further 9 percentage points to 28%.

	Electrification share	Electricity intensity
2000	15.48571801	534
2001	15.62833692	543
2002	15.92059275	531
2003	16.07453151	542
2004	16.06696465	539
2005	16.32310299	539
2006	16.61738605	540
2007	16.97149649	544
2008	17.09858399	533
2009	17.17596986	528
2010	17.45173285	526
2011	17.74762652	534
2012	17.97909501	532
2013	18.2154703	528
2014	18.38150952	517
2015	18.48704244	502
2016	18.80317969	487
2017	19.04595195	484
2018	19.37935002	475
2025	20.90469203	332.15
2030	23.11783419	220.79
2035	25.63565523	125.99
2040	28.13516925	68.77
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In contrast, the carbon intensity of electricity generation is off track. Having remained flat between 2000 and 2010, a significant global transformation of the power sector had begun, with energy intensity dropping 10% from 2010 to 2018. However, even though renewables contributed the most to meeting global electricity demand growth in 2018, coal- and gas-fired power generation still increased. Although the carbon intensity of electricity generation declined almost 2% in 2018 (from 484 gCO2/kWh to 475 gCO2/kWh), the slowdown in reductions over the last two years means the improvement rate is off track with what would be needed by 2040 under the SDS.

With electrification rate expected to accelerate, more efforts are needed to support low-carbon technology deployment, including CCUS, as well as early retirement of unabated coal-fired plants.

Energy intensity

The energy intensity indicator tracks total primary energy demand per unit of GDP.

In 2018, global energy intensity improved by only 1.3%, the third consecutive annual decline from the 2.9% improvement in 2015. In contrast, reaching the SDS requires that energy intensity reductions accelerate to the unprecedented level of 3.5% annually through to 2040, meaning that total primary energy demand barely grows over today’s level, despite continued economic growth.

Average annual change in energy intensity

Energy intensity improvement has slowed down for the third consecutive year, falling only 1.3% in 2018, in contrast with the unprecedented 3.5% average annual rate of decline required to 2030 under the SDS.

	Annual change	2018	SDS
1990-2013 average	-1.463		
2014	-2.863		
2015	-2.468		
2016	-2.269		
2017	-1.693		
2018		-1.3	
2018-2040 average			-3.442

Falling energy intensity was the main factor behind the flattening of global energy-related CO2 emissions from 2013‑2016, as it offset three-quarters of the impact of GDP growth. Sectoral analysis of energy efficiency shows that even though policy coverage has been expanding, the rate of increase in recent years has been lower than in the early 2010s.

Energy efficiency

Energy efficiency improved by just over 1% in 2017, with a 15% improvement overall between 2000 and 2017 in IEA countries and other major economies. It has been the main driver of decoupling of economic growth and energy consumption: without energy efficiency improvements, global emissions would have been nearly 4 gigatonnes of CO2 equivalent (GtCO2‑eq) higher in 2017.

Energy savings potential due to efficiency

Energy efficiency has improved by an estimated 15% since 2000 in IEA countries and other major economies; but the additional global energy efficiency savings of up to 16% in 2040 can be realised if we go beyond current and announced policies.

	Energy use	Energy savings since 2000	Energy savings potential to 2040
2000	7036		
2017	9682	1484	
2040	10463		2957
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Efficiency gains were not sufficient to counter balance activity growth, however, resulting in a net increase in final energy consumption between 2000 and 2017. Government policies have been pivotal in achieving these energy efficiency gains, but recent weakening in both their coverage and stringency global energy efficiency improvements in 2017.

In the SDS, total final consumption remains close to the 2017 level up to 2040, while the economy will more than double. Energy efficiency improvements will therefore play a critical role in achieving this outcome. Given the ample efficiency potential identified the SDS, additional energy savings in final energy consumption could be 16% higher in 2040 than what current and announced policies would deliver.

Low-carbon investment in clean energy transition

Energy investment decisions provide a preview of what types of technologies are going to be developed or are about to be built. Likewise, tracking the share of clean energy investment gives an indication of the trajectory of clean energy technology deployment into the future as well as the extent to which investment flows are shifting towards clean energy technologies.

In 2018, the share of overall clean energy investment, covering both low-carbon power and efficiency, stood at 34%, where it remained stalled over the past years.

Share of clean energy and network investment in total energy sector investment

The share of clean energy investments overall – covering both low-carbon power and efficiency – stalled in recent years and needs a rapid boost to keep Paris in sight. In 2018 it stood at 34%, in the SDS, it rises to 68% by 2040.

Investment shares in the SDS 	Clean energy investment	Network investment
2014	26.39422612	12
2015	29.84539937	14.41260171
2016	33.34437958	16.25862005
2017	33.69912695	16.01502564
2018	33.6	15.8805
2020	42	12.84945443
2025	60.728167	12.41572386
2030	65.33920135	14.15158572
2035	66.24454765	16.98355436
2040	68	17
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Note: Clean energy investment includes renewables, nuclear and end-use efficiency.

In the SDS, total energy investments rise 98% from today’s level by 2040, with a marked shift towards clean energy: the share of clean energy investments in the energy sector increases to 68% in 2040. While absolute electricity network investments increase in the SDS, the share in total investment remains relatively stable at around 16% in 2040 due to a substantial increase in energy efficiency investments.

Importantly, the SDS shows that only 13% more investment in the energy sector is required up to 2040 than what would be needed if countries were to stay on the current course of existing and planned decarbonisation policies. Much more capital needs to be allocated to end-use efficiency and clean energy technologies, however.

Subsector indicators

Subsector indicators are also needed to obtain metrics that can be used to design and implement policies and measures for specific energy subsectors. These indicators can serve as tools to monitor progress as well as provide insights on how to target policy interventions. A set of key sectoral indicators is available for power, buildings, transport and industry on sectoral TCEP pages.






Transport CO2 emissions




Total transport-related final energy consumption per GDP




Energy efficiency policy coverage in transport (% of new vehicle sales covered by regulations)




Share of EVs in new vehicles sales




Share of biofuels use in transport (of total liquid fuels)




Industry CO2 emissions




Industrial productivity: industrial value added/final industrial energy use




Mandatory policy coverage of industrial energy use




CO2 intensity of industrial energy supply




Buildings CO2 emissions




Buildings sector energy performance (intensity) (total final energy used per m2)




Mandatory Energy efficiency policy coverage of building energy use




Power CO2 emissions




Share of low-carbon power generation in overall power generation




Average CO2 intensity of electricity generation (gCO2/kWh)




CO2 intensity of power generation from new investments (gCO2/kWh)




Share of new low-carbon power generation investment in overall new power generation investment