Zero-Carbon Power

A key milestone on the route to Net Zero

How the climate front-runners are discovering that zero-carbon electricity in the 2030s is key to meeting 2050 neutrality targets

Published April 2021

Author: Dr Chris Rosslowe


We analyse the latest energy scenarios informing UK and EU policy-making, and compare these with the announced US target for a zero-carbon electricity system by 2035. Commonalities offer insights into the actions required in the next 10-15 years to align with mid-century net-zero targets.

  • An ‘unspoken consensus’ is revealed between the UK, EU and US that a clean electricity supply in the 2030s is crucial for net-zero by 2050
  • A rapid end to coal-fired electricity can be seen across all scenarios, with major reductions before 2030
  • Wind and solar become the dominant source of electricity from 2030 in the UK and EU, and the US could achieve the same. 
  • Electricity generation from fossil gas declines in all regions in the next decade. A complete phase-out of unabated gas is recommended by 2035 in the UK and the same is implied by the US target.
  • Twenty-nine countries are committed to net-zero by 2050, including ten G20 members and over half of the OECD. However, these mid-century targets are not universally founded upon low carbon electricity in the next decade.

The stage is set for a high-ambition coalition on zero-carbon power by 2035 to emerge. Actions taken by this coalition could drive emissions reductions in the next decade, while adding integrity to net-zero targets. 

“There’s an emerging consensus among climate leaders that zero-carbon power systems in the 2030s are essential for net-zero. The idea that clean electricity can be a foundation for economy-wide decarbonisation is not new, but now it has entered mainstream thinking. Leaders committed to mid-century climate neutrality should heed the emerging consensus and join the US in targeting zero-carbon power by 2035. A high-ambition coalition could play a pivotal role in beginning to align policy and finance towards this goal.”

Dr Chris Rosslowe

Energy & Climate Data Analyst, Ember

Background to this briefing

Soon after taking office, President Biden issued an Executive Order on Tackling the Climate Crisis at Home and Abroad. This included the promise of a “carbon pollution-free electricity sector no later than 2035”. The pledge is reaffirmed in the updated US NDC, released during the Leader’s climate summit.

This target is the first of its kind from a major economy, however, in this briefing we reveal the US isn’t alone in aiming for a zero-carbon electricity system in the 2030s. Official analyses by the UK’s Climate Change Committee (CCC) and the EU Commission (EU-COM) both point towards very low carbon electricity by 2035 or soon after. Like Biden’s 2035 power target, the implications of the UK and EU analyses are yet to be fully reflected in policy, but they tell a common story that reaching net-zero emissions by 2050 requires a zero-carbon electricity system long before that date.

Recent years have seen a growing number of countries commit to net-zero by mid-century. On the eve of the Leader’s climate summit, 29 countries (plus the EU) were committed to net-zero, including half of the OECD (21/37 members). While this is encouraging, anticipated emissions reductions in the next decade are not sufficient to remain on track to meet the Paris goals. Key to getting the world on track will be phasing-out coal from global power systems, starting with OECD nations no later than 2030. The emerging consensus revealed by this briefing suggests the time could be right to extend a similar benchmark to all fossil fuels by 2035.


Comparing plans for power

The electricity supplies in all three regions have been tending towards lower carbon intensity for several years. Going forward, official energy scenarios show continuing declines to near-zero carbon between 2035 and 2040 (see methodology for the scenarios considered). The UK and EU have a head-start on the US, however, such is the ambition of Biden’s 2035 target that the US is set to make up ground quickly. 


Here we summarise what the available scenarios mean for the power sectors in the UK, EU, and US. We focus on three essential themes:

  1. Phasing out existing fossil-fired generation, and implications for new capacity.
  2. Ramping up solar and wind, to both replace fossil generation and meet growing demand.  
  3. Clean firm power and flexibility options to back up renewables-dominated systems. 


1) Phasing out fossils


A rapid end to coal-fired electricity can be seen across all scenarios, with major reductions before 2030. The UK will phase-out coal power completely by 2024. The US target implies coal phase-out before 2035, and a recent review of energy modelling studies concludes this could and should happen by 2030. Such an outcome would be inline with the UN Secretary-General’s OECD countries like the US to exit coal power by 2030. In the EU, previous analysis of the EU-COM figures by Ecologic and Climact revealed room for only 50TWh (approx) of coal-fired electricity in 2030, equivalent to 2% of production. This implication is, however, yet to sink in with some member states. Coal generation in Poland’s recent energy plan would exceed this limit alone. This is without considering Germany’s 2038 phase-out date, or discussions in Czechia to exit coal no sooner than 2033. 

Electricity generation from fossil gas declines in all regions in the next decade. A complete phase-out of unabated gas is recommended by 2035 in the UK and the same is implied by the US target. The EU figures leave more room for unabated gas, with generation falling 10% by 2030 and 63% by 2050 (compared to 2020). 

Regarding new fossil generation capacity, evidence for the UK and US suggests little if any need for new fossil gas capacity. The UK CCC advise no new unabated gas capacity after 2030, and to ensure that everything deployed after 2025 is robustly ready for CCS or hydrogen burning. The UC Berkeley ‘90% clean’ scenario demonstrates how the US can achieve the 2035 goal while reducing existing gas capacity by half. Similar conclusions cannot be concluded from the EU-COM scenarios directly, but the common end-point of very low carbon electricity in the 2030s has a shared implication for new gas assets in the UK, US, and EU. Well before the end of their economic lifetimes (typically 25 years), any new fossil gas assets will be required to operate with either low load factors or low carbon emissions (CCS or low-carbon gas).


2) Ramping up wind and solar


Wind and solar become the dominant source of electricity from 2030 in the UK and EU, and the US could achieve the same.

Scenarios for the UK and EU show huge increases in electricity generation from wind and solar. Together they become the dominant source of electricity from 2030 and reach 80% (UK) and 67% (EU) by 2050. In the US, a similar rise to dominance for wind and solar by 2030 is indicated by the Berkeley ‘90% clean’ scenario.



All scenarios analysed will require unprecedented expansion of wind and solar capacity, requiring a step-change in deployment rates if existing capacity targets are to be hit. The UK offshore wind fleet will have to grow by 2.7GW per year to meet the official target of 40GW by 2030, and the CCC estimate of 95G by 2050. Average growth between 2010-2019 was 1GW per year. In the EU, offshore wind growth will need to increase from 1.1GW per year (2010-2019) to 6.5GW per year to hit the 2030 target of 60GW in the offshore wind strategy. Onshore wind growth will need to double to 18GW per year in order to reach the capacity indicated in the EU-COM scenario.

The acceleration of deployment required in the US seems even greater. To keep pace with the ‘90% clean’ scenario, combined growth of the wind and solar fleet would have to average 100GW per year until 2035, compared to an average of 13GW over the last 5 years (EIA). Aligning policy and unlocking finance to deliver the infrastructure needed is a core challenge for all administrations.


3) System flexibility and low-carbon firm power


With electricity systems dominated by wind and solar after 2030, we compare how the scenarios propose to meet the challenge of integrating these sources while securing supply at all times. 

Both the UK and EU scenarios assume approximately stable nuclear generation and capacity until 2050. This implies new capacity to replace those nuclear plants expected to retire or close early as a result of policy. Relatively, nuclear’s contribution to the generation mix falls in both cases from 17% (UK) and 25% (EU) today to around 10% in 2050. 

After 2030, scenarios for the EU and UK feature currently unproven low-carbon dispatchable sources, however, the low carbon intensities reached in the 2030s are not contingent on these technologies. Their contributions remain small even in 2050. Low-carbon dispatchable sources (hydropower, bioenergy, fossil CCS, and BECCS) provide a 10% in the UK and 20% in the EU in 2050. If hydropower is excluded, these contributions are 8% and 16% respectively. 

Both UK and EU scenarios acknowledge the importance of strengthened transmission grids and electricity storage, which combine to limit curtailment of the large wind and solar fleet by 2050. Interconnection of the UK with neighbouring countries doubles by 2030 and triples by 2050. Electricity storage is provided by 18GW of batteries in 2035 and hydrogen plays an increasing role thereafter. In the EU, the latest network plan sees interconnection capacity across the continent increase by 10% by 2030. Furthermore, the EU system integration strategy features energy efficiency, energy storage and the synergies between renewable electricity and hydrogen electrolysis as key themes. 

It’s not clear how the US plans to provide low-carbon firm power. The 90% clean scenario maintains current output levels from non-fossil sources until 2035 (mostly nuclear and hydropower). Battery storage is quickly and cost-effectively scaled up to reach 150GW (600GWh) by 2035 and covers 20% of demand. It is also widely acknowledged that an expanded transmission system will be required, although estimates of the extent vary.


Zero-carbon power by 2035: a new challenge for the OECD

In the wake of the US leaders’ summit in April, and in advance of COP26, the stage is set for a high-ambition coalition on zero-carbon power by 2035 to emerge. Following in the footsteps of the successful Powering Past Coal Alliance (PPCA), this coalition could spur international progress towards clean electricity while adding integrity to net-zero targets. The PPCA was instrumental in forging a consensus that OECD countries should be coal-free by 2030. The emerging consensus revealed by this briefing suggests the time could be right to extend a similar benchmark to all fossil fuels by 2035.

Six of the G7 and 21 of the 37 OECD members have set net-zero goals for 2050. However, these targets are lacking the support of zero-carbon power goals for the 2030s, including coal phase-out commitments no later than 2030.

  • Japan is the only member of the G7 without a coal phase-out commitment. 
  • Germany’s coal phase-out date of 2038 is the latest in the G7 and incompatible with the Paris agreement. 
  • In the OECD:
    • Of the 37 members, 21 are targeting net-zero and 18 have coal policies aligned with the Paris agreement (phase-out before 2030). Only 14 can claim both. This would rise to 15 were the US to announce coal phase-out by 2030. 
    • Japan and South Korea are the highest coal users in the OECD committed to net-zero without accompanying this with a coal phase-out commitment. They are also the 4th and 5th largest coal users in the world.

The disparities between net-zero targets and near-term power sector plans expose a credibility gap that must be closed. Coal phase-out is just the first step in this process. Leaders committed to mid-century climate neutrality should heed the emerging consensus and join the US in a commitment to zero-carbon power by 2035. 


Notes on methodology:

  • Historic carbon intensities in Figure 1 are calculated using generation data reported in Ember’s Global Electricity Review (2021). Standard carbon intensities for each fuel type were applied for all regions. These were 850gCO2/kWh for hard coal, 1050gCO2/kWh for lignite (EU only), 400gCO2/kWh for fossil gas, and 650gCO2/kWh for other fossil fuels. A more accurate approach would account for regional differences in intensity by fuel type. However, we found that applying these standard intensities to fuel-specific generation data reproduced reported power sector emissions with reasonable accuracy (within 10%). 
  • Future carbon intensity for the UK was taken as presented by the CCC for the balanced pathway. It was not possible to confirm whether carbon intensities by fuel are consistent between historic calculations and future predictions.  
  • Future carbon intensity for the EU supply was calculated using data extracted from the EU Commission’s 2030 Impact Assessment (IA). Power sector emissions for policy scenarios are given in Table 39 of the Annex, from which we take 289MtCO2 for the MIX scenario in 2030. Generation data presented in Figure 46 of the Annex shows approximately 200TWh of unabated fossil in 2050, which we assume to be all fossil gas, and by use of emissions factors estimate power sector emissions of 80MtCO2. The trajectory of emissions between these points is implied from Figure 20. Power sector emissions in 2035 in the MIX scenario are estimated to be 200±20MtCO2. 
  • Figures 3-5 assume even annual growth in wind and solar capacity to achieve the capacity totals available for 2030, 2035, 2040, 2045, or 2050. This is not equivalent to deployment, which will have to be higher to account for retirements.


Summary of scenarios forming the basis of UK-EU-US comparison in this briefing

UK CCC Balanced pathway

The ‘Balanced pathway’ by the UK CCC – independent climate advisors to the UK government. This is one of several scenarios forming the evidence base for the sixth carbon budget advice to the UK Government. In the words of the CCC, the Balanced pathway “makes moderate assumptions on behavioural change and innovation and takes actions in the coming decade to develop multiple options for later”. In April 2021 the UK Government announced it will accept the advice of the CCC and set a new emissions reduction target for 2035.

EU Commission MIX scenario

The ‘MIX’ scenario presented by the European Commission as part of the impact assessment for raising the EU‘s 2030 greenhouse gas reduction target. This scenario, along with three other so-called ‘policy scenarios’, delivers -55% GHG emissions by 2030. The MIX scenario achieves these reductions by extending the scope of the ETS to buildings, road transport and intra-EU aviation and maritime navigation. It also models a ‘medium’ increase in ambition in renewables and energy efficiency policies. In April 2021 the -55% target – informed by this impact assessment – was agreed by co-legislators on the European Climate Law. 

US – UC Berkeley ‘90% clean’ scenario (2035 report)

In lieu of any detail about how “carbon pollution-free power” by 2035 will be achieved, we consider a range of analyses. One of the few studies to focus specifically on the 2035 target is the 2035 report by UC Berkeley (UCB), which presents a ‘90% clean’ scenario, whereby 90% of electricity generation is provided by clean sources, i.e., sources not producing carbon emissions (a category in which the authors include bioenergy).