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Introduction: Cities in the Twin Net-Zero and Digital Transition

Oleg Golubchikov1 and Komali Yenneti2

1 School of Geography and Planning, Cardiff University, Cardiff, Wales, UK

2 School of Architecture and Built Environment, University of Wolverhampton, Wolverhampton, England, UK

1.1 The Rise of Smart Energy Cities

The future of cities is going to be digital and that future is also to be low-carbon. To use the language of modellers, there is a high confidence level that the future will be both digital and low-carbon: there are simply too many symptoms pointing us in that direction. But how can we make sense of these two dimensions of the urban future, digital and low-carbon? To what extent are they co-constitutive of one another? For example, how will the cities of the future harness digital innovations to optimise energy consumption, reduce greenhouse gases (GHGs) and achieve overall sustainability? Are those futures already shaping the cities of today? If so, what do these experiences of today tell us about the future, as much as they do about the current trends? These are some of the concerns as well as inspirations underlying this volume.

The global consensus about the need to limit global warming to 1.5?°C and global pressures for climate mitigation have far-reaching implications for cities. Accounting for GHG emissions inside and outside urban areas, the urban share of combined global CO2 and CH4 emissions was estimated 67-72% in 2020 (IPCC 2022). These emissions are certainly unevenly distributed across the world, with cities in high- and upper-middle-income countries contributing as much as an estimated 86% of global urban CO2 emissions in 2015 (Mukim and Roberts 2023). However, as urbanisation is more rapid in the rest of the world, the share of cities in lower-income countries also increases. This means that cities around the world, as a 'global collective', and irrespective of their location, are seen as a key target for climate mitigation and 'deep decarbonisation' to achieve zero or near net-zero emissions (Seto et al. 2021).

Since the 'climate change problem is principally an energy problem' (MacKay 2009, p. 16) - the acknowledgement that it is fossil fuels that make the greatest contribution to GHG emission - actions addressing energy (reducing energy demand, switching energy provision to low-carbon supply and improving energy efficiency) are what climate governance at the urban level seeks to prioritise. Indeed, many socio-technical systems that contribute to GHG emissions, such as electricity systems, heating and transport, get 'densified' at the scale of the city, overlaying and interplaying with one another. Consequently, the whole variety of urban sectors and urban practices are implicated in the push for low-carbon transition: energy infrastructure, the built environment, the construction sector, industries, business and public services, transport and mobility, natural environments, waste and water management, food and other consumption practices, people's lifestyle and behavioural patterns, urban design and urban planning (Bulkeley et al. 2010; Golubchikov 2011; IPCC 2022; Seto et al. 2021).

The increasing digitalisation of society and the advent of 'smart city' add a new dimension to the urban climate agenda - the promise of leveraging digital innovation for accelerated energy transitions and decarbonisation. While there are no universal definitions for 'smart cities', the common denominator is the use of Information and Communications Technology (ICT) and automation for the improvements of urban processes, services and infrastructure (UNECE and ITU 2016). Wireless connectivity, the Internet of Things (IoT), big data and robotics have all been part of this trend, with artificial intelligence (AI) also becoming increasingly prominent at the urban scale (Cugurullo et al. 2023; Golubchikov and Thornbush 2020, 2022). Smart city has consequently gained wide currency in international practice with the promise of integration, efficiency, sustainability and people-centricity (Thornbush and Golubchikov 2020).

Smart buildings, smart water management, intelligent transport systems and smart waste management systems are a few developments that tap into digitally-enabled technologies in order to contribute to the promise of urban-scale decarbonisation. In parallel developments, energy systems are also becoming 'smart' and transitioning to net-zero and distributed/decentralised/micro-generation systems. Smart urban energy systems become an integral part of urban climate governance, offering solutions that not only optimise energy usage but also promote resilience and adaptability in the face of changing environmental and social dynamics. Smart energy systems can operate on a cross-system level, including the management of electricity via smart grids across different urban systems, or be integrated into particular urban systems, for example, buildings, with the deployment of smart energy meters, smart thermostats, battery storage, smart hot water tanks and electric vehicle charges, to name a few technologies. The relationships between providers of energy and users of energy also change; for example, enabled by smart energy systems the built environment becomes the infrastructure for energy generation and storage.

What essentially combines these various trends and developments is the notion of smart energy cities (Thornbush and Golubchikov 2021). Smart energy cities can be seen as part of the evolution of the city-energy-sustainability nexus, also tapping into the opportunities that digital transition brings for managing energy demand, energy supply and energy flows within urban domains, where digitally-enhanced smart cities and energy transitions represent mutually supporting processes. Combining the developments in ICT-led smart cities and sustainable energy, the notion of the smart energy city has come close to represent a digitally-mediated variant of low-carbon cities. Smart energy city, in its different manifestations, is consequently one of the central elements emerging from the discussions in the present volume.

Many cities have already incorporated smart, climate and energy targets into their strategies and plans, with a growing 'club' of cities that declare their intent to become carbon-neutral, climate-neutral, climate-smart, or net-zero in the near future. The European Union's 100 climate-neutral and smart cities (European Union 2022) or India's climate-smart cities initiative (NIUA-C3 2020) are examples of even larger-scale commitments to net-zero cities and sustainable urban development. Other cities and regions around the world are also making strides towards achieving similar goals (Bulkeley and Stripple 2021; Mendes 2022).

The technology-centred visions for net-zero and digital transitions are not without their problems, however. The smart city concept in particular has been widely critiqued for its tendency to glorify technology, where citizens become subordinate to, rather than placed at the heart of, a sustainable city project and where the city's actual needs are often circumvented by the availability of technology (Luque-Ayala and Marvin 2020). As some lines of critique suggested (Yigitcanlar et al. 2019), policymakers often opt for 'Black Box' technology solutions promoted by technology companies, rather than producing long-term visions for the 'good city'. Relatedly, the issues around social justice - in particular, how costs and benefits are distributed and who is included in smart and low-carbon urban transitions - have become an important part of academic and policy conversations (Golubchikov 2020).

In response, the concept of 'smart city' has also morphed over time: from what some now call 'Smart City 1.0' (characterised by a top-down framework, with a focus on ICT infrastructure and deploying solutions promoted by technological companies) to 'Smart City 2.0' (a people-focused, users-friendly framework) and even to 'Smart City 3.0' (a framework for inclusive and participatory urban governance, even if still technology-enhanced) (Golubchikov 2020). The active involvement of stakeholders - including citizens - in the co-creation and implementation of smart city solutions is now claimed, in theory at least, to be the key to improving transparency and incentivising society towards more sustainable practices and behaviours. With regard to technologies, instead of their uncritical deployment, there is now a search for solutions that are tailored to specific needs of individual cities and communities.

This volume further explores how cities - in particular, their energy systems - are being re-shaped by smartisation and decarbonisation (as encapsulated in the notions of the twin net-zero and digital transition and smart energy cities) and with what consequences for wider society. The volume draws together insights and case studies from across a variety of disciplines - from smart energy grids to active and energy-efficient...