This chapter identifies systems where dispersed multiphase flow is important as well as the key fluid physics via important engineered and natural systems. This includes energy systems and propulsion systems, manufacturing, processing and transport systems, as well as environmental and biological systems. In addition, this chapter sets forth key terminology and assumptions for dispersed multiphase flow, the key velocity reference frames used for multiphase flow, and the assumption of continuum conditions.

This chapter explores the integrated potential of future technological and social innovations enabling sharing in future energy systems. Energy systems around the world are undergoing a transformation toward more distributed, renewable-based configurations where new mechanisms for “sharing” are evolving. Future energy systems are likely to integrate a regionally appropriate mix of electricity generation that is dispatched, stored, and distributed through sophisticated platforms that enable sharing of electricity at multiple scales. Sharing in future energy systems has the potential to radically disrupt relationships governing utilities, energy consumers, and distributed electricity generation at the individual and household levels, at the community and organizational levels, and at the regional, state, national, and even international levels. Innovations may allow formerly passive consumers to become actively engaged in producing and managing electricity which could shift the locus of organizational decision making and control away from traditional utilities. Prosumers who can “share” their electricity may be empowered to change the rules that have governed their relationships with utilities for the past century. We consider a potential “death spiral of utilities’ business model” as new sharing platforms, including community-level energy cooperatives, emerge to replace the conventional approach to managing and distributing energy. This chapter also explores how future energy sharing might connect with the concept of energy democracy.

Tapping the power of fossil fuels over the past century and a half has propelled a massive expansion of human enterprise and prosperity, yet it has also released toxic amounts of carbon dioxide into the atmosphere, thereby endangering the future viability of human civilization. If global average temperatures rise 4 to 6 degrees above the level of preindustrial times, climate scientists nearly unanimously conclude that severe disruptions of global ecosystems will result. These disruptions include: self-reinforcing spirals of global warming caused by feedback factors like melting permafrost, ice loss, water vapor, and wildfires; acidification of ocean waters and flooding of coastal regions as sea level rises by as much as one foot per decade; growing frequency of severe weather events such as droughts, floods, superstorms, and heat waves; the spread of tropical diseases into temperate regions; and the collapse of agriculture in many parts of the planet, leading to waves of desperate climate refugees.

The transition toward sustainable energy systems poses a most prominent societal challenge for decades to come. We demonstrate that the alignment framework provides a set of rich instruments for exploring this field of research. It allows us to disentangle the complex interrelations between the technologies and institutions required to provide expected services and safeguard the critical functions at the core of network infrastructures. Since the energy transition requires structural changes in the technological architecture and the macro-institutions, this chapter focuses on this most generic layer of analysis. In order to illustrate our approach, we compare and analyze three archetypes, namely, traditional, contemporary, and future energy systems. Using a comparative static approach, we identify (in)compatibilities between the technological and institutional characteristics of different coordination arrangements when it comes to safeguarding the critical functions throughout the energy transition. We show that the alignment framework provides an innovative approach for understanding and analyzing these complex changes. This analysis of future energy systems represents an important step toward understanding the consequences of the energy transition and the possible evolution of existing energy systems.