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The UK has been one of the few countries that has successfully decoupled final energy consumption from economic growth over the past 15 years. This study investigates the drivers of final energy consumption in the UK productive sectors between 1997 and 2013 using a decomposition analysis that incorporates two novel features. Firstly, it investigates to what extent changes in thermodynamic efficiency have contributed to overall changes in sectoral energy intensities. Secondly, it analyses how much of the structural change in the UK economy is driven by the offshoring of energy-intensive production overseas. The results show that energy intensity reductions are the strongest factor reducing energy consumption. However, only a third of the energy savings from energy intensity reductions can be attributed to reductions in thermodynamic efficiency with reductions in the exergy intensity of production making up the reminder. In addition the majority of energy savings from structural change are a result of offshoring, which constitutes the second biggest factor reducing energy consumption. In recent years the contributions of all decomposition factors have been declining with very little change in energy consumption after 2009. This suggests that a return to the strong reductions in energy consumption observed between 2001 and 2009 in the UK productive sectors should not be taken for granted. Given that further reductions in UK final energy consumption are needed to achieve global targets for climate change mitigation, additional policy interventions are needed. Such policies should adopt a holistic approach, taking into account all sectors in the UK economy as well as the relationship between the structural change in the UK and in the global supply chains delivering the goods and service for consumption and investment in the UK. [ABSTRACT FROM AUTHOR]

Mitigating climate change is driving the need to decarbonize the electricity sector, for which various possible technological options exist, alongside uncertainty over which options are preferable in terms of cost, emissions reductions, and energy security. To reduce this uncertainty, we here quantify two questions for the power system of Great Britain (England, Wales and Scotland): First, when compared within the same high-resolution modeling framework, how much do different combinations of technologies differ in these three respects? Second, how strongly does the cost and availability of grid-scale storage affect overall system cost, and would it favor some technology combinations above others? We compare three main possible generation technologies: (1) renewables, (2) nuclear, and (3) fossil fuels (with/without carbon capture and storage). Our results show that across a wide range of these combinations, the overall costs remain similar, implying that different configurations are equally feasible both technically and economically. However, the most economically favorable scenarios are not necessarily favorable in terms of emissions or energy security. The availability of grid-scale storage in scenarios with little dispatchable generation can reduce overall levelized electricity cost by up to 50%, depending on storage capacity costs. The UK can rely on its domestic wind and solar PV generation at lower renewable shares, with levelized costs only rising more than 10% above the mean of 0.084 GBP/kWh for shares of 50% and below at a 70% share, which is 35% higher. However, for more than an 80% renewable generation share to be economically feasible, large-scale storage, significantly more power imports, or domestic dispatchable renewables like tidal range must be available. [ABSTRACT FROM AUTHOR]

• An accelerated EV program is needed to meet 2050 CO2 emission targets for the UK. • Even under accelerated uptake, few CO 2 benefits will be seen before 2030. • The lack of impact before 2030 derives from slow vehicle stock turnover. • With embedded production CO2, 2050 UK targets will need intense grid decarbonisation. • There is an urgent need to pursue both EV uptake and demand side solutions. The decarbonisation of the road transport sector is increasingly seen as a necessary component to meet global and national targets as specified in the Paris Agreement. It may be achieved best by shifting from Internal Combustion Engine (ICE) cars to Electric Vehicles (EVs). However, the transition to a low carbon mode of transport will not be instantaneous and any policy or technological change implemented now will take years to have the desired effect. Within this paper we show how on-road emission factors of EVs and models of embedded CO 2 in the vehicle production may be combined with statistics for vehicle uptake/replacement to forecast future transport emissions. We demonstrate that EVs, when compared to an efficient ICE, provide few benefits in terms of CO 2 mitigation until 2030. However, between 2030 and 2050, predicted CO 2 savings under the different EV uptake and decarbonisation scenarios begin to diverge with larger CO 2 savings seen for the accelerated EV uptake. This work shows that simply focusing on on-road emissions is insufficient to model the future CO 2 impact of transport. Instead a more complete production calculation must be combined with an EV uptake model. Using this extended model, our scenarios show how the lack of difference between a Business as Usual and accelerated EV uptake scenario can be explained by the time-lag in cause and effect between policy changes and the desired change in the vehicle fleet. Our work reveals that current UK policy is unlikely to achieve the desired reduction in transport-based CO 2 by 2030. If embedded CO 2 is included as part of the transport emissions sector, then all possible UK EV scenarios will miss the reduction target for 2050 unless this is combined with intense decarbonisation (80% of 1990 levels) of the UK electricity grid. This result highlights that whilst EVs offer an important contribution to decarbonisation in the transport sector it will be necessary to look at other transport mitigation strategies, such as modal shift to public transit, car sharing and demand management, to achieve both near-term and long-term mitigation targets. [ABSTRACT FROM AUTHOR]

• A comparative societal exergy analysis of Ghana and the United Kingdom is performed. • Ghana's projected 5 %/year economic growth requires primary energy growth of 2 %/year. • Energy efficiency measures are ineffective due to economy-wide feedbacks. • Energy intensity is not an appropriate metric for primary energy reduction goals. • Absolute decoupling of energy from gross domestic product appears mission impossible. To meet climate change mitigation objectives, international institutions have adopted targets aimed at reducing or ending growth of primary energy consumption. Simultaneously, continued economic growth is forecasted to meet human development goals. Together, declining energy consumption and rising gross domestic product (GDP) is called "absolute decoupling." However, absolute decoupling is unprecedented for the world economy as a whole (since at least 1971). Is absolute decoupling "Mission impossible?" Given the high stakes, we need a clearer understanding of the extent of future energy–GDP decoupling. To gain that understanding, we perform societal exergy analyses using a novel Physical Supply Use Table framework to assess historical and future trends of primary energy consumption and economic growth for one medium human development index country and one very high human development index country, Ghana and the United Kingdom (UK), respectively. Three key results are obtained. First, we find that it will be very difficult to absolutely decouple primary energy consumption from economic activity. This is particularly true for Ghana's rapidly growing economy, where projected economic growth of 5.0 %/year will require growth of primary energy consumption of around 2.0 %/year. It is also true for the UK, where at best primary energy consumption appears constant into the future to provide a projected GDP growth of 2.7 %/year. Second, we find that energy efficiency is not an effective means to reduce primary energy consumption and associated carbon dioxide emissions due to economy-wide feedback effects, placing greater importance on decarbonizing the primary energy supply. Third, we find primary energy intensity is not an appropriate metric to measure energy reduction progress, because meeting primary energy intensity targets does not ensure absolute decoupling will occur. At present, absolute decoupling appears to be mission impossible. [ABSTRACT FROM AUTHOR]