Granular technologies to accelerate decarbonization

Of the 45 energy technologies deemed critical by the International Energy Agency for meeting global climate targets, 38 need to improve substan- tially in cost and performance while accelerating deployment over the next decades.Low-carbon technological solutions vary in scale from solar panels, e-bikes, and smart thermostats to carbon capture and storage, light rail transit, and whole-building retrofits. We make three contributions to long-standing debates on the appropriate scale of technological responses in the energy system. First, we focus on the specific needs of accelerated low-carbon transformation: rapid technology deployment, escaping lock-in, and social legitimacy. Second, we synthesize evidence on energy end-use technologies in homes, transport, and industry, as well as electricity generation and energy supply. Third, we go beyond technical and economic considerations to include innovation, investment, deployment, social, and equity criteria for assessing the relative advantage of alternative technologies as a function of their scale. We suggest numerous potential advantages of more-granular energy technologies for accelerating progress toward climate targets, as well as the conditions on which such progress depends

Dynamics of the water-energy nexuses of Mumbai and London

The urban water-energy nexus sits at the intersection of three global challenges: urbanisation, global freshwater scarcity, and climate change caused by energy use. The concept recognises the various interactions between water and energy systems at all stages, as well as the concentration of service demand in cities which drives most of global resource use. Research indicates that end use is the largest component of the nexus, both in terms of energy and of water. However, the interactions on the level of energy and water supply and wastewater have received most attention, part of the reason being the difficulty in characterising end use. There is still a lack of knowledge about the end-use linkages in cities, and about their role in urban dynamics. This research elucidates the urban water-energy nexus with a conceptualisation, a comprehensive appraisal of its components and an investigation of its dynamics. To this end, I developed a system dynamics model for London as a case study, and expanded on it for Mumbai as an example of a city in the Global South for which research of this kind has been thin. The models have at their core a novel end-use structure with bidirectional water-energy interactions by service, and also represent population dynamics, the urban water system, environmental constraints and a tax based climate policy. The results show that end-use interactions play an important role in determining future resource consumption. In London, disregarding them in planning may lock in energy-intensive water supply, while in Mumbai it may perpetuate intermittent water supply. More applications of this kind are needed for global conclusions, and I provide methods for extending the model to the diversity of cities. This work ultimately implies that the end-use water-energy interactions should be more prominent in urban sustainability debates and planning.Open Acces

A Review of Urban Water-energy Linkages in End-use: A Call for Joint Demand Studies

Aims: A literature review to show the importance of combined water and energy demand end-use studies and to illustrate techniques that can be applied for these analyses. Study Design: A review of energy-related water end-use and water-related energy end-use studies. Place and Duration of Study: Cited studies on urban water/energy use are mainly based on the work done in the UK, Australia or the US, which has been completed over the course of the past decades but mainly in recent years. Methodology: An overview included studies focused on the different energy and water end-uses in cities, their quantification and methods for estimating those end-uses using aggregate indicators such as total energy or water use. Particular focus was given to the estimation of water-related energy and energy-related water. Results: Up-to-date research has been focused on the disaggregation of the actual end-use for energy and for water separately, estimating the corresponding water/energy use. There is considerable uncertainty about the joint end-use of water and energy, and the implications of this linkage for the overall water and energy supply at the city level. Conclusion: Combined water/energy end-use is an important end-use component. Water and energy end-uses have been studied extensively in isolation using empirical approaches. However, there is a need for empirical studies of the combined water/energy end-uses that can greatly reduce the uncertainties on the feedbacks between the two systems, and benefit both utilities and end-users