• Energy Research

We used the TIMER energy model to explore the potential role of hydrogen in the energy systems of India and Western Europe, looking at the impacts on its main incentives: climate policy, energy security and urban air pollution. We found that hydrogen will not play a major role in both regions without considerable cost reductions, mainly in fuel cell technology. Also, energy taxation policy is essential for hydrogen penetration and India's lower energy taxes limit India's capacity to favour hydrogen. Once available to the (European) energy system, hydrogen can decrease the cost of CO2 emission reduction by increasing the potential for carbon capture technology. However, climate policy alone is insufficient to speed up the transition. Hydrogen diversifies energy imports; especially for Europe it decreases oil imports, while increasing imports of coal and natural gas. For India, it provides an opportunity to decrease oil imports and use indigenous coal resources in the transport sector. Hydrogen improves urban air quality by shifting emissions from urban transport to hydrogen production facilities. However, for total net emissions we found a sensitive trade-off between lower emissions at end-use (in transport) and higher emissions from hydrogen production, depending on local policy for hydrogen production facilities.

Abstract Rising affluence and a warming climate mean that the demand for air conditioning (AC) is rising rapidly, as society adapts to climate extremes. Here we present findings from a new methodological framework to flexibly couple and emulate these growing demands into a global integrated assessment model (IAM), subsequently representing the positive feedbacks between rising temperatures, growth in cooling demand, and carbon emissions. In assessing global and regional climate change impacts on cooling energy demand, the emulator incorporates climate model uncertainties and can explore behavioural and adaptation-related assumptions on setpoint temperature and access to cooling. It is also agnostic to the emissions and climate warming trajectory, enabling the IAM to run new policy-relevant scenarios (Current Policies, 2 °C and 1.5 °C) with climate impacts that do not follow Representative Concentration Pathways. We find that climate model uncertainty has a significant effect, more than doubling the increase in electricity demand, when comparing the 95th percentile cases to the median of the climate model ensemble. Residential AC cooling energy demands are expected to increase by 150% by 2050 whilst providing universal access to AC would result in the order of a 400% increase. Depending on the region, under current policies and limited mitigation, climate change could bring in the order of 10%–20% higher cooling-related electricity demands by 2050, and approximately 50% by 2100. Set point temperature has an important moderating role—increasing internal set-point from 23 °C to 26 °C, approximately halves the growth in electricity demand, for the majority of scenarios and regions. This effect is so strong that the change in set point temperature to both residential and commercial sectors outweighs the growth in demand that would occur by providing universal access to AC by 2050 to the 40% of the global population who would otherwise not afford it.

To meet ambitious global climate targets, mitigation effort in China and India is necessary. This paper presents an analysis of the scientific literature on how effort-sharing approaches affect emission allowances and abatement costs of China and India. We find that reductions for both China and India differ greatly in time, across- and within approaches and between concentration stabilisation targets. For China, allocated emission allowances in 2020 are substantially below baseline projections. Moreover, they may be below 2005 emission levels, particularly for low concentration targets (below 490ppm CO 2-eq). Effort-sharing approaches based on allocating reduction targets lead to relatively lower reductions for China than approaches that are based on allocating emission allowances. For 2050, emission allowances for China are 50-80% below 2005 levels for low concentration targets with minor differences between approaches. Still, mitigation costs of China (including emissions trading) remain mostly below global average. According to literature, Chinese emission allowances peak before 2025-2030 for low concentration targets. India's emission allowances show high increases compared to 2005 levels. If emission trading is allowed, financial revenues from selling credits might compensate mitigation costs in most approaches, even for low concentration targets. India's emission allowances peak around 2030-2040 for all concentration targets.

Most modelling studies that explore emission mitigation scenarios only look into least-cost emission pathways, induced by a carbon tax. This means that European policies targeting specific - sometimes relatively costly - technologies, such as electric cars and advanced insulation measures, are usually not evaluated as part of cost-optimal scenarios. This study explores an emission mitigation scenario for Europe up to 2050, taking as a starting point specific emission reduction options instead of a carbon tax. The purpose is to identify the potential of each of these policies and identify trade-offs between sectoral policies in achieving emission reduction targets. The reduction options evaluated in this paper together lead to a reduction of 65% of 1990 CO2-equivalent emissions by 2050. More bottom-up modelling exercises, like the one presented here, provide a promising starting point to evaluate policy options that are currently considered by policy makers.

AbstractThe building sector in China is responsible for 40% of total energy‐related CO2 emissions, driven by its large population, continuous economic growth, and construction boom. In addition to greenhouse gas (GHG) emissions from energy use, buildings drive significant emissions for construction activities and production of energy‐intensive materials, such as steel and cement. While supply‐side energy strategies have been extensively explored, a demand‐side perspective that considers stock dynamics and circularity improvements is essential to assess sustainable pathways for the buildings sector. Here, we explore a set of decarbonization scenarios for the building sector in China considering a range of circular strategies and their interplay with different climate policies. The strategies include lifetime extension of buildings, switch to wood‐based construction, reduction of per‐capita floorspace, and a combination of all three strategies. We use the building sector model MESSAGEix‐Buildings soft linked to the integrated assessment model (IAM) MESSAGEix‐GLOBIOM and prospective life cycle assessment (LCA) to assess the effects of these circular strategies on building material and energy demands, and operational and embodied emissions. We find that the three strategies could reduce building material demand up to 60% on mass basis by 2060 compared to a reference scenario with continuation of current policies. This translates into a reduction of embodied and total GHG emissions of 62% and 24%, respectively, significantly contributing to achieving decarbonization targets. Integrating industrial ecology methods in IAMs, as demonstrated in this study, can provide valuable insights to inform national policy decisions on mitigation strategies accounting for both demand and supply sides.

The residential sector plays an important role in the energy system of developing countries. In this paper we introduce a bottom up simulation model for household energy use. The model describes energy demand for several end-use functions based on a set of physical drivers, such as floor space and heating degree days. The model also recognizes different population groups: i.e. urban and rural households, each distinguishing five income quintiles. The model is applied to analyze possible future developments of residential energy use in five developing world regions: India, China, South East Asia, South Africa and Brazil. We find that in each of these regions cooking is currently the main end-use function, but that other functions, such as space heating, cooling and appliances become more important. At the same time, energy consumption slowly shifts towards modern fuels. The model also shows that climate policy can reduce residential energy emissions, but could also slow down the energy transition away from traditional fuels in low income classes.