UK National Grid looks at energy scenarios for net zero in 2050

15 July 2021

A new report by UK grid operator National Grid ESO on 2021 Future Energy Scenarios (FES) looks at the prospects for net zero in 2050. It says reaching net zero by 2050 is possible “as long as we work together urgently to reduce our emissions and agree clear ways forward”. The 167-page FES 2021 outlines four pathways for the future of energy from now to 2050. “These scenarios are not forecasts or predictions, but they do represent a credible range of likely outcomes and are used by the National Grid ESO and other energy network owners/operators as a fundamental part of annual network planning and operability analysis.” The first FES document was published in 2011 and the scenarios have evolved since then.

All four FES 2021 scenarios have lower emissions by 2030 compared with FES 2020. Three of those reach net zero by 2050. The Consumer Transformation and System Transformation scenarios represent two different ways to get there either by changing energy use or by changing the way energy generate and supply. Leading the Way is a scenario which combines high consumer engagement and world-leading technology and investment to enable the fastest credible decarbonisation journey. In this scenario, the UK reaches net zero in 2047 and goes on to reduce emissions by 103% by 2050 (compared with 1990 levels). Decarbonisation is slowest in the Steady Progression scenario, where 2050 emissions are reduced by 73% compared with 1990 levels.

In addition to reducing emissions by lowering demand and moving to zero-carbon energy, there are three ways to support net zero greenhouse gas emissions, the report notes:

  • Using bioenergy so that emissions are offset by biomass growth. Burning sustainably sourced wood or other sustainable bioenergy crops instead of fossil fuels means the CO2 emitted can be offset by the CO2 they have absorbed over their life.
  • Continuing to produce fossil emissions but capturing the greenhouse gases before they are released into the atmosphere - Carbon Capture Usage and Storage (CCUS). Capture rates are expected to range between 90 and 98% by 2050 across the FES 2021 scenarios.
  • Actively removing greenhouse gases - this can be done using natural options such as creating new forests/woodland areas (afforestation), replanting trees in old forests (reforestation) and peatland restoration. Another approach is to combine CCUS with the use of bioenergy - Bioenergy with Carbon Capture and Storage (BECCS). New technology is also under development to capture CO2 directly from the atmosphere. Direct Air Carbon Capture and Storage (DACCS) involves a chemical process which absorbs CO2 from a flow of air. However, this is in the early stages of development.

Leading the Way, System Transformation and Consumer Transformation all meet net zero by 2050. Leading the Way reaches net zero by 2047 and goes on to achieve annual net emissions of -28 MtCO2e by 2050, a removal of 28 million tonnes of greenhouse gas (GHG) emissions from the atmosphere annually.

The report looks at hydrogen supply, noting that “nuclear energy combined with low temperature electrolysis has been modelled for the first time this year based on stakeholder feedback and is used in both System Transformation and Consumer Transformation”. Electrolysis from wind or solar power is the main production source for Leading the Way and Consumer Transformation.

Key insights listed in the report include:

  • The use of BECCS means makes it possible to achieve overall net negative emissions in the power sector.
  • Increased electricity peak demands compared with FES 2020 indicates the need more generation capacity, particularly renewables, as well as flexible technologies and demand side response.
  • As unabated gas generation is phased out in the 2030s in the net zero scenarios, maintaining system security will be challenging. This will need the accelerated uptake of zero carbon technologies and CCUS.
  • The profile of electricity supply is changing with demand side response playing a central role in flexibility, which will ensure security of supply in a more efficient way.
  • Connecting high volumes of new renewable generation, particularly offshore wind, to the electricity system will be challenging in the short term due to the need for network reinforcement.

The report notes that today’s electricity mix is made up primarily of gas, renewables and nuclear, supplemented by a few other sources.

Renewable generation capacity, primarily wind and solar, has increased fivefold over the past 10 years. This has been supported by government subsidies, such as the Feed-In Tariff and the Contracts for Difference scheme but has also been driven by rapid reductions in cost.

Across all scenarios there is an increase in renewable generation, particularly offshore wind, which grows to make up over half of electricity supply by the late 2030s in all scenarios. Natural gas as a proportion of output reduces through the 2020s, displaced by renewables as the largest share of generation. In 2050 wind, solar, nuclear and BECCS provide over 90% of generation output in all scenarios.

Power sector carbon emissions are expected to fall rapidly in the early 2020s in all scenarios. The commissioning of Hinkley Point C contributes to emissions falling further in the mid to late 2020s. In the net zero scenarios, gas generation continues reducing rapidly through the 2020s and 2030s. The late 2020s also see the first BECCS plants commissioned in the net zero scenarios, delivering negative emissions. BECCS plays an important role as one of the sources of negative emissions that can offset low residual emissions from electricity generation and other sectors. 

Looking at nuclear, the report says “nuclear generation will continue to be affected by stations reaching the end of their life through the 2020s”. Hinkley Point C is expected to come online in the mid-2020s which helps offset some of this decline, but nuclear capacity does not recover to current levels in any scenario until post-2035. This is due to the very long lead times on new nuclear projects. While there are no other large-scale nuclear projects at advanced stages of development, the government aims to bring one large nuclear project to final investment decision by the close of Parliament in 2024.

The Consumer Transformation scenario relies primarily on small modular reactors (SMRs) with the first deployed from the early 2030s in line with the aims of the Advanced Nuclear and to bring forward demonstrator projects. These are significantly smaller than the GW-scale traditional nuclear reactors and are designed to be more easily replicable and scalable. The System Transformation scenario, however, primarily sees the development of traditional large-scale nuclear projects. The lower energy demands of the Leading the Way scenario see only very limited new nuclear development after Hinkley Point C.

Electricity system flexibility today is predominantly delivered on the supply side. As demand varies through the day, different sources of electricity are brought online. Some like nuclear operate more as ‘baseload’ generation, running constantly, other than for periods of maintenance, while others such as natural gas turbines are more flexible.

Electrolysis plays an important role as a source of flexibility in the net zero scenarios, able to ramp up demand rapidly to match renewable output and producing hydrogen that can be stored until it is needed.

The Leading the Way scenario sees the earliest development of significant electrolysis capacity, reaching over 10 GW by 2034, followed by the other net zero scenarios by 2041. There is only limited development of electrolysis production in the Steady Progression scenario due to limited demand for hydrogen and, because the electricity sector is not decarbonised, hydrogen produced from electrolysis is not zero carbon.

In the Consumer Transformation and System Transformation scenarios some electrolysis capacity developed in the 2030s is connected directly to new nuclear generation, allowing these generators to operate in baseload. At times of low demand, nuclear-connected electrolysis increases to absorb excess power from the reactor. This makes up a relatively small proportion of total electrolysis capacity in these scenarios in 2050 - 7% in Consumer Transformation and 14% in System Transformation.

In response to the National Grid’s FES 2021, Nuclear Industry Association CEO Tom Greatrex said: “National Grid’s scenarios show that we need new nuclear to hit net zero, including replacing existing capacity by the mid-2030s, and expansion thereafter. But to meet the growing demand for clean power, the UK should have even more ambitious targets for nuclear, our only proven source of firm, emissions-free power.

“We should also strive to produce as much of that power ourselves, to safeguard Britain’s energy security. Interconnectors have a key role in stabilising our energy system, but we should not make our road to net zero dependent on other countries’ energy policies. Nuclear investment is a sure path to better jobs, lower emissions, and security of supply.”

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