The limitations of a supply-centric approach

Decarbonising energy supply has led to significant advances. The cost of renewable energy has fallen dramatically, and its share of global electricity generation continues to rise [2,3]. However, these gains have not translated into commensurate emissions reductions. Global carbon emissions remain stubbornly high. A key reason for this paradox is that energy demand continues to grow, often outpacing the decarbonisation of supply [4].

A supply-side focus also fails to address the inefficiencies embedded in how energy is consumed. Even the cleanest electricity is wasted if used to power inefficient buildings, outdated industrial processes, or poorly designed transport systems. Without addressing these inefficiencies, the challenge of achieving net-zero emissions becomes exponentially more difficult, as ever-increasing amounts of clean energy are required to compensate for avoidable waste.

And historically, energy efficiency has been the main driver of carbon emission reduction delivering significantly more carbon reduction than renewables [5].

The case for demand-side decarbonisation

Decarbonising demand is not merely about reducing energy consumption; it is about using energy more efficiently and intelligently. Key strategies include:

• Energy efficiency: Improving efficiency is the single most immediate and cost-effective method of reducing emissions. Insulation upgrades, energy-efficient appliances, and modernised industrial processes can significantly reduce energy consumption. According to the IEA, efficiency measures alone could contribute over 40% of the emissions reductions required to meet global climate targets [6].
• Demand flexibility and system optimisation: The timing of energy use is as important as its volume [5]. In other words, when we use energy is increasingly just as important or even more important as how much energy we consumer. By shifting demand to align with periods of high renewable energy generation, the reliance on fossil fuel backup power is reduced. Technologies such as smart meters, dynamic pricing, and automated energy management systems enable more efficient energy consumption patterns, balancing supply and demand more effectively.
• Electrification of end-uses: Replacing fossil fuel-based systems with electricity-powered alternatives - particularly for heating, transport, and industrial processes - can yield significant efficiency gains and emissions reductions [7]. However, electrification must be accompanied by demand-side measures to ensure that increased electricity use does not undermine overall system efficiency.
• Behavioural and structural changes: Technology alone cannot achieve full decarbonisation. Behavioural shifts and systemic transformations—such as increasing public transport use, promoting cycling and walking, and reducing material consumption—play a crucial role in reducing energy demand. The Intergovernmental Panel on Climate Change (IPCC) has recognised the importance of demand-side solutions in its Sixth Assessment Report (AR6), dedicating an entire chapter - “Chapter 5: Demand, Services, and Social Aspects of Mitigation” - to exploring their role in climate mitigation [8]. The report underscores that reducing energy consumption through behavioural, structural, and service-oriented approaches is a critical yet often underutilised strategy.

Beyond emissions: the co-benefits of demand-side solutions

A demand-centric approach to decarbonisation offers significant benefits beyond emissions reductions, many of which have been well-documented in previous research:

• Energy system resilience: Lower and more flexible demand reduces stress on electricity grids, enhancing resilience to supply disruptions and extreme weather events [9].
• Economic benefits: Energy efficiency lowers costs for households, businesses, and governments. Reducing overall energy demand mitigates exposure to volatile energy prices and supply chain disruptions [10].
• Health and environmental gains: Lower energy consumption results in reduced air pollution, leading to fewer respiratory and cardiovascular diseases [11]. A demand-first approach also minimises the environmental footprint of energy infrastructure, reducing land and resource use [12].

Expanding the policy and technological toolkit

A demand-side approach expands the range of available decarbonisation strategies, unlocking innovative solutions such as:

• Mobilising flexibility: Analysis shows that unlocking demand flexibility can unlock substantial economic, technical, and behavioural benefits [13]. These include reduced peak demand and required generation and grid capacity, reduced grid congestion, and reduced costs to consumers.
• Smart urban infrastructure: Cities designed with energy-efficient buildings, intelligent transportation networks, and integrated renewable energy systems can significantly lower per capita energy demand [14].
• Circular economy principles: Designing products and supply chains to minimise waste and maximise material and energy efficiency reduces overall energy consumption [15].

Conclusion: asking the right questions

The decarbonisation of energy supply is essential but insufficient to achieve net-zero emissions on its own. A demand-focused perspective enables a more systemic, cost-effective, and resilient energy transition. By addressing how much energy we use, how efficiently we use it, and when and where we use it, we unlock new pathways to decarbonisation.

The cleanest energy is the energy that does not need to be produced. By embracing this principle, we can accelerate decarbonisation, enhance energy security, and build a more sustainable and equitable future. It is time to redefine the energy transition debate - moving beyond supply-side solutions and embracing the transformative potential of demand-side decarbonisation.