Energy demand reduction options for meeting national zero-emission targets in the United Kingdom

Since the Paris Agreement, global assessments have underscored the role of reducing final energy demand in meeting climate targets by alleviating pressure on supply decarbonization and reducing reliance on carbon dioxide removal (CDR). However, global final energy demand continues to grow, partly met by fossil fuels, and decarbonization is progressing too slowly to meet stringent goals. As mitigation responsibilities and policies are national, and many current pledges fall short of limiting warming to 1.5 °C, there is a need to focus on demand reduction within national strategies, especially in high-use countries. This study addresses that gap by developing a comprehensive, replicable national framework for estimating the potential of final energy demand reduction, applied to the United Kingdom. It examines whether a country in the global North can halve energy demand by 2050 without reducing quality of life, how this affects reliance on CDR, investment needs, and the feasibility of more ambitious climate targets.

The paper situates its work within literature showing strong mitigation potential from demand-side measures. Previous scenarios such as Grubler et al.’s Low Energy Demand (LED) scenario indicate up to 40–56% global or global North energy demand reductions, potentially avoiding the need for engineered CDR. IEA’s Sustainable Development Scenario and Net Zero by 2050 roadmaps emphasize energy efficiency investments as central to decarbonization. Work by Kikstra et al. suggests efficiency-led, COVID-19-related demand changes can lower mitigation costs. Broader literatures address reductions via lifestyle, behavior, and social change. Despite these insights, most comprehensive analyses are global or multi-national, with a paucity of national-level scenarios directly informing policy. This study responds by providing a detailed national framework and application for the UK.

The study proposes and applies a five-step national framework integrating sectoral demand modelling with a whole-system energy model to quantify demand reduction contributions to net-zero targets. Step 1: Develop a scenario narrative grounded in seven observed trends affecting energy demand: digitalization; sharing and circular economy; energy efficiency; healthy society; environmental awareness; globalization; and work and automation. Step 2: Conduct sector-level modelling with appropriate tools per sector to derive energy service demands and their evolution: Mobility via TEAM-UK (Transport Energy Air pollution Model for the UK); Nutrition and Materials & Products via hybrid UK MRIO models (with a bespoke construction model across 36 applications and 17 built-asset categories); Residential (Shelter) via the UK National Household Model (NHM); Non-domestic buildings via a bespoke model based on the BEES dataset assessing technical savings and uptake trajectories. Step 3: Identify and iteratively map inter-linkages to ensure consistency, e.g., between shelter, mobility, and non-domestic space use; construction material demands from infrastructure and buildings; manufacturing impacts from vehicle sales; land-use effects from dietary shifts influencing forestry availability. Step 4: Integrate sector outputs into UKTM, a technology-explicit, whole-system, partial-equilibrium TIMES model for the UK. Sector models provide exogenous energy service-demand projections and alignment on technology efficiency and deployment constraints; UKTM endogenously determines least-cost supply-side evolution, balancing demands for electricity, hydrogen, and other vectors, and accounting for energy and key non-energy GHGs. Specific integrations include: • Mobility: service-demand projections by subsector (except shipping), alignment on vehicle efficiencies and deployment rates. • Shelter: exogenous space and water heating service demands; UKTM retrofit options switched off to avoid double counting; alignment on heat pump deployment and performance. • Non-domestic: import non-replacement efficiency gains (fabric, controls, management systems) and constrain roll-out by scenario; electrification handled endogenously; floor space trajectories drive service demand. • Materials & Products (Industry): apply resource efficiency gains to UKTM growth drivers (from EDM) and adjust for infrastructure construction changes (e.g., steel, cement). • Nutrition (Agriculture & Land): align CH4 and N2O emission trajectories with sectoral modelling; free land from dietary shifts constrains forestry and energy crop potentials; food waste trajectories aligned. Step 5: Construct four coherent scenarios with common narratives: Ignore (existing 2018 UK policies only), Steer (targets net zero but falls short; primarily efficiency), Shift (net-zero target with ambitious demand-side interventions feasible under current framings), Transform (net-zero with transformative technological, social, infrastructural, and institutional changes delivering demand reductions and co-benefits). Additional UKTM-only comparators include Ignore Demand and Steer demand variants. The framework evaluates implications for final energy, supply transformation, CDR reliance, system costs, investments, and feasibility of tighter carbon budgets.

• Final energy demand reductions: Transform achieves a 52% reduction by 2050 relative to 2020; Shift 41%; Steer (efficiency-focused) 31%; Ignore about 5%. Transform delivers >50% sectoral reductions across most sectors (transport >60%), with industry reducing less than other sectors. • Per-capita energy use: Transform reaches ~40 GJ per person by 2050, below the current global average (55 GJ) and far below the OECD average (116 GJ). • Role of avoid/shift vs efficiency: In Shift and especially Transform, avoid/shift measures (societal and structural changes) contribute substantially alongside efficiency, with sectoral variation (buildings rely relatively more on efficiency). • CDR reliance: Under Steer, engineered removals (BECCS and DAC) total 49 MtCO2e in 2050, rising to 76 MtCO2e when accounting for the residual emissions gap to net zero. Shift more than halves this to 37 MtCO2e. Transform requires no engineered removals; nature-based removals can reach up to 60 MtCO2e by 2050, though net zero can be achieved with <30 MtCO2e of nature-based removal. • Electricity system scale-up: All scenarios require decarbonized and expanded electricity. Generation increases by about 150% in Steer, 94% in Shift, and 44% in Transform relative to 2020, reducing the need for complex generation (e.g., nuclear, BECCS power) in lower-demand scenarios. • System costs and investments: Overall system costs in 2050 are about 20–40% lower in Shift and Transform relative to Steer; overall investment needs in low-carbon infrastructure and technologies are reduced, easing capital-raising challenges. • Cumulative emissions and near-term reductions: Demand-side measures enable earlier mitigation. Under a tighter cumulative carbon budget, cumulative CO2 emissions fall to 3.87 GtCO2 versus 4.82 GtCO2 in Transform. By 2030, emissions fall 47% (tighter-budget Transform) vs 41% (Transform) vs 37% (Steer) relative to 2020, preserving headroom for further ambition ratcheting.

The findings demonstrate that deep reductions in national final energy demand can substantially facilitate achieving net-zero targets while preserving or improving quality of life through co-benefits such as health, cleaner air, and better work-life balance. By incorporating avoid and shift strategies alongside efficiency, the framework reveals higher achievable reductions than efficiency-only approaches, thereby reducing dependence on high-risk, unproven engineered CDR and moderating the scale and complexity of supply-side transitions. The smaller energy system in low-demand scenarios lowers system costs, reduces infrastructure build-out challenges, and enhances the feasibility of meeting near- and medium-term targets, enabling stronger nationally determined contributions and lower cumulative emissions. The national focus fills a gap in the literature by providing policy-relevant pathways tailored to country-specific contexts, capturing inter-sectoral linkages and whole-system implications.

The study introduces a replicable, bottom-up national framework integrating sector-specific demand modelling with a whole-system energy model to quantify the contribution of energy demand reduction to climate targets. Applied to the UK, it shows that halving final energy demand by 2050 is feasible without compromising quality of life, delivering per-capita energy use near 40 GJ, significantly reducing or eliminating reliance on engineered CDR, lowering electricity system expansion needs, and cutting system costs and investments. Demand-led strategies also enable earlier emissions reductions and support tighter cumulative carbon budgets, preserving scope to ratchet climate ambition. Future research should strengthen the linkage from narrative to granular policy packages, assess macroeconomic effects and rebounds of demand-led transitions, design just and equitable transition pathways, and address structural change, investment, and stranded asset risks. The framework can guide other countries in assessing and implementing demand-side strategies alongside supply decarbonization.

• Scope and model detail: Shipping was not included in TEAM-UK and handled separately; UKTM’s agriculture detail is limited, with alignment via CH4 and N2O emissions trajectories rather than detailed production technologies. • Exogenous drivers: GDP and population are exogenous and unchanged across scenarios; macroeconomic feedbacks of substantially lower energy demand are not captured. • Scenario nature: The analysis presents simulated, narrative-driven scenarios rather than forecasts; results depend on assumptions about technology performance, deployment constraints, behavior, and policy feasibility. • National context specificity: Implementation potential varies by country; the UK’s current energy use and offshored industrial production affect comparability to the broader global North. • Social and political feasibility: Large-scale societal and structural changes entail acceptance, policy coordination, and governance challenges; rebound effects are uncertain and require integrated policy to mitigate. • CDR and technology uncertainties: Risks around engineered CDR scale-up and acceptance of large infrastructure remain; nature-based removal potentials depend on land-use trade-offs. • Sectoral integration uncertainties: Despite iterative alignment, some differences between sectoral models and UKTM outputs remain due to endogenization and aggregation.