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

Global energy demand continues to grow, fueled by economic expansion and increasing energy service demands. Despite improvements in energy efficiency, the growth is largely met by fossil fuels, outpacing the development of low-carbon alternatives. This necessitates a greater focus on reducing energy demand to meet stringent climate targets. The Paris Agreement emphasizes national-level responsibility for emissions reduction. Many countries have set net-zero targets, but current pledges are insufficient to achieve the 1.5°C goal. This study addresses the gap in national-level energy demand reduction scenarios by developing a comprehensive framework, applied here to the UK. The framework assesses the potential for energy demand reduction to contribute to net-zero emissions, examining measures beyond energy efficiency improvements. The UK is a suitable case study due to its legally binding emission reduction targets and extensive experience with decarbonization pathway analysis.

Existing research highlights the crucial role of reducing final energy demand in meeting climate goals. Studies like Grubler et al. (2018) show that substantial global energy demand reductions are possible, even eliminating the need for carbon dioxide removal (CDR). The International Energy Agency (IEA) also emphasizes the importance of energy efficiency improvements through technological advancements. However, comprehensive assessments focusing on national-level energy demand reduction are limited. While global analyses provide a valuable framework, climate policies are implemented nationally, creating a policy relevance gap. This research addresses that gap by focusing specifically on the UK's potential for energy demand reduction to achieve its ambitious climate targets.

The researchers developed a five-step national modelling framework (illustrated in Figure 1): 1. **Scenario Narrative Development:** Seven key trends influencing future energy demand were identified (digitalization, sharing economy, energy efficiency, healthy society, environmental awareness, globalization, and work/automation). These trends formed the basis for consistent scenario narratives across sectors. 2. **Sector-Level Modelling:** Appropriate models were used for each sector: TEAM-UK for mobility, hybrid UK MRIO models for materials/products and nutrition, a national household model for residential energy, and bespoke models for non-domestic buildings and industry. These models projected energy service demands under different scenarios. 3. **Inter-linkage Identification:** An iterative process mapped dependencies between sectors to ensure scenario consistency. For example, changes in working patterns affect mobility and non-domestic building demands. 4. **Whole-System Integration:** The energy service demands and other assumptions from the sector models were integrated into the UKTM (UK Technology Model), a whole-system energy model that optimizes energy supply based on demand projections. 5. **Coherent Scenario Creation:** Four internally consistent scenarios were created (Ignore, Steer, Shift, Transform), each with a distinct narrative and level of energy demand reduction. The Ignore scenario represents current policies, while the others explore progressively ambitious energy demand reduction strategies.

The analysis revealed that significant reductions in final energy consumption are feasible in the UK. The most ambitious scenario, "Transform," projected a 52% reduction by 2050 compared to 2020 levels. This contrasts with the "Steer" scenario, which relied solely on energy efficiency improvements and achieved a 31% reduction, falling short of the net-zero target. The "Transform" scenario achieved per capita energy use of 40 GJ, substantially below the global average of 55 GJ and the OECD average of 116 GJ. The study highlighted that the "Transform" and "Shift" scenarios, achieving substantial demand reductions, eliminated the need for large-scale engineered CDR (Carbon Dioxide Removal) technologies, such as BECCS or direct air capture. Furthermore, the lower energy demand scenarios reduced investment needs in energy system infrastructure by 20-40%, easing the transition to a decarbonized energy system. The earlier mitigation from demand-side actions also created the opportunity to ratchet up climate ambition further, achieving even lower cumulative emissions. The decomposition of energy demand reductions in the "Shift" and "Transform" scenarios showed a significant contribution from avoid/shift measures, highlighting the importance of broader societal changes beyond mere efficiency improvements (Figure 3). Avoid/shift measures were especially critical in the "Transform" scenario.

The findings demonstrate the substantial untapped potential for energy demand reduction in high-energy-consuming countries. The research independently replicates the scale of reductions suggested by previous global assessments. The variation in reduction levels across sectors underscores the importance of context-specific scenario development. While many identified interventions are transferable to other nations, their implementation level varies. The framework presented here offers a replicable template for assessing the contribution of various interventions to meeting national emission targets. The combination of detailed sectorial models and a systems integration model, guided by a comprehensive scenario narrative that accounts for sectoral interlinkages, constitutes the strength of this approach. Without energy demand reduction, achieving short-term climate targets becomes highly challenging, and long-term ambitions would rely heavily on unproven and potentially expensive CDR technologies. This research underscores the crucial role of demand-side strategies in accelerating the transition to net-zero emissions.

This study reveals substantial and currently underexplored potential for energy demand reduction in high-energy-consuming countries like the UK. The "Transform" scenario, while ambitious, does not depict a drastically different future, emphasizing achievable changes involving improved efficiency, structural shifts, and altered societal practices without sacrificing essential energy services. Future research should strengthen the link between scenario narratives and detailed sectoral measures to inform effective policy packages. Additional analysis is required to ensure a just and equitable transition, assess economic impacts, and address complex investment and stranded asset challenges.

The study acknowledges the potential for rebound effects, where energy savings from efficiency improvements are offset by increased energy consumption due to other factors. While these effects are difficult to quantify, they can be mitigated through broader societal shifts toward sustainable production and consumption, decarbonization, and targeted policy interventions. Further research is needed to better understand and mitigate macro-level rebounds in demand-led transitions. Additionally, the economic, social, and political implications of large-scale energy demand reduction warrant careful consideration.