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Special Focus: Pathways towards a decarbonised economy

4.2 COP 21 scenarios – a carbon budget approach

Below +1.5°C at the end of the century with
a carbon budget

Distributed Energy (DE) and Global Ambition (GA) (also referred to as “COP21 Scenarios”) scenarios are meant to assess sensible pathways to reach the target set by the Paris Agreement for the COP21: 1.5°C or at least well below 2°C by the end of the century. For the purpose of the TYNDP scenarios, this target has been translated by ENTSO-E and ENTSOG into a carbon budget to stay below +1.5°C at the end of the century with a 66.7 % probability2.

A carbon budget defined with environmental organisations

To limit the global warming to +1.5°C by the end of the century, there is a maximum quantity of GHG the EU – including the energy system – can emit. This defines the carbon budget for the EU, and to a more restrictive extent, the share allocated to the energy system that the COP21 scenarios consider. To define the carbon budget until the year 2100, ENTSO-E and ENTSOG have worked with the environmental NGOs Renewable Grid Initiative and Climate Action Network Europe.

A carbon neutral energy system by 2050

The other objective set in the COP21 scenarios is to reach carbon neutrality3 of the energy system by 2050. This objective therefore places further demands on the speed of decarbonisation the energy system should reach.

Carbon neutrality can be reached by 2050 within a budget of 61 GtCO …

Both Distributed Energy and Global Ambition scenarios show that a centralised or decentralised evolution of the energy system can achieve carbon neutrality by 2050. The scenarios also show that, considering different development of technologies – and starting from 2018 onwards – the energy system can limit its emissions to reach not more than 64.2 GtCO₂ at EU level until 2050 in Global Ambition, and not more than 61.4 GtCO₂ in Distributed Energy.

… but negative emissions are needed after 2050

However, the scenario budget defined to limit the global warming to 1.5°C with a 66.7 % probability considers that the cumulative EU GHG emissions should be limited to 48.5 GtCO₂ by the end of the 21st century. This means net negative emissions of 15.7 GtCO₂ have to be achieved between 2050 and 2100 in case of Global Ambition, provided the EU is carbon neutral in 2050. For Distributed Energy, due to lower cumulative emissions until 2050, 12.9 GtCO₂ of net negative emissions are needed to reach the 1.5°C target by 2100.

² The Intergovernmental Panel on Climate Change, Special Report, 2018,

³ “Carbon neutrality (or net zero) means having a balance between emitting carbon and absorbing carbon from the atmosphere in carbon sinks. Removing carbon oxide from the atmosphere and then storing it is known as carbon sequestration. In order to achieve net zero emissions,
all worldwide greenhouse gas emissions will have to be counterbalanced by carbon sequestration” (European Parliament). The ENTSOs consider all greenhouse gas emissions measured in terms of their carbon dioxide equivalence.

GHG emissions compared to 1990 level

Figure 2

Figure 2: GHG emissions in ENTSOs’ Scenarios

EU 28 cumulative GHG emissions – Global Ambition

Figure 3a
Cumulative non-CO₂ emissions1,5345,1358,40111,31113,84416,00017,780
Cumulative CO₂ emissions6,74321,95334,68644,99553,00859,07563,504
Cumulative credits from pre- and post-combustive CCS00-136-679-1,673-3,034-4,676
Cumulative credits from BECCS000-32-128-356-808
Cumulative credits from LULUCF-627-2,253-3,963-5,757-7,635-9,598-11,644
Net Cumulative CO₂eq emissions7,65024,83538,98849,83857,41662,08764,155

EU 28 cumulative GHG emissions – Distributed Energy

Figure 3b
Cumulative non-CO₂ emissions1,5345,1328,39411,29813,82115,96317,725
Cumulative CO₂ emissions6,73521,98534,48643,86050,45654,78457,113
Cumulative credits from pre- and postcombstive CCS00-56-260-642-1,165-1,778
Cumulative credits from BECCS0000000
Cumulative credits from LULUCF-627-2,253-3,963-5,757-7,635-9,598-11,644
Net Cumulative CO₂eq emissions7,64224,86438,86049,14155,99959,98461,416

Figure 3: EU28 Cumulative Emissions in COP21 Scenarios in MtCO2

Energy and non-energy related CO2 emissions57.1Carbon-­NeutralityAdditional measures needed, e.g.:
Non-CO2 GHG emissions (including methane and Fluorinated gases)* 17.7
Carbon sinks**-13.4
Net cumulative
61.4-13EU28 carbon budget share based on its population
48.5 GtCO

* Data for methane and fluorinated gases emissions is taken from the European Commission’s most ambitious 1.5Tech and 1.5Life scenarios (­average) as published in the “A Clean Planet for all”-Study “A Clean Planet for all”- Study
** Data for LULUFC is taken from the European Commission’s most ambitious 1.5Tech and 1.5Life scenarios (average) as published in the “A Clean Planet for all”-Study “A Clean Planet for all”- Study

Table 1: Cumulative emissions and required net negative emissions in Distributed Energy

4.3 Sector-Coupling – an enabler for (full) decarbonisation

For ENTSOG and ENTSO-E, sector coupling describes interlinkages between energy carriers, related technologies and infrastructure. Major processes in this regard are gas-fired power generation, Power-to-Gas ( P2G ) as part of the broader Power-to-X and hybrid demand technologies.

ENTSOs’ scenarios are dependent on further development of sector coupling, without these interlinkages a high or even full decarbonisation in the energy sector will not be reached.

Assuming a switch from carbon-intensive coal to natural gas in 2025, a minimum of 85 MtCO₂ could be avoided in the power generation. With increasing shares of renewable and decarbonised gases, gas-fired power plants become the main “back-up” for variable RES in the long-term. Distributed Energy even shows a further need for CCS for gas power plants to reach its ambitious target of full decarbonisation in power generation by 2040.

On the other hand, P2G becomes an enabler for the integration of variable RES and an option to decarbonise the gas supply. Hydrogen and synthetic methane or liquids allow for carbon-neutral energy use in the final sectors. Distributed Energy is the scenario with the highest need for P2G and P2L, requiring 1,460 TWh of dedicated power generation4 per year with more than 490 GW of capacities for wind and solar in 2040 to produce renewable gas.

Sector coupling in National Trends, with the assumption that P2G generation is limited to substitute otherwise curtailed electricity supply, amounts to 27 TWh with 22 GW of P2G to produce renewable gas.

4 According to the P2G and P2L modelling approach, the dedicated wind and solar is simulated outside the integrated electricity system.