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Today’s energy sectors hold different potentials for saving on energy, carbon, and other greenhouse gases (GHGs). Buildings, for instance, represent more than 40% of energy use worldwide and one-third of GHGs (United Nations Environment Programme [UNEP], n.d.a). Improvements in heating, cooling, and powering of buildings, as well as industrial processes, can deliver substantial and cost-effective savings. In line with this, geothermal energy represents a more unusual form of renewable energy in that it can directly contribute to heating, cooling, and electricity services. Unlike a number of its counterparts, geothermal energy can provide a more stable and renewable form of energy that is largely unaffected by weather. The chapter focuses on geothermal energy adoption in Iceland, “a little country that roars,” according to UNFCCC Executive Secretary Christina Figueres (Iceland Monitor, 2014), when discussing leadership in renewable energy use and related action. In developing its renewable energy leadership, Iceland has wrestled, like many countries, with tradeoffs in energy, the environment, and economic development. The chapter highlights the interplay of these interests and explores the innovative engineering and industrial spillovers in Iceland’s geothermal adoption. Iceland is a country of roughly 333,000 people, and is a global leader in renewable energy use (Islandsbanki, 2010; Ministry of the Environment, 2010; Statistics Iceland, 2017). Two-thirds of the country’s primary energy consists of geothermal energy, with roughly nine out of ten Icelandic homes heated by the fuel source and a quarter of the country’s electricity powered by it (Orkustofnun, 2015; Ragnarsson, 2015). The nation leads globally in terms of geothermal heat capacity per capita and serves as a principal source of international training and consulting on geothermal energy, with a diverse industrial cluster that has developed around the technology (Gekon, n.d.; United Nations University Geothermal Training Programme [UN- GTP], n.d). The country’s low carbon development pathway reflects choices and debate about how to manage its natural resources and allow for foreign investment. Iceland began the 20th century as one of the poorest nations in Europe and is now a top-ranked country in the United Nations Development Program’s Human Development Index (Hannibalsson, 2008; United Nations Development Program [UNDP], 2015).

As discussed in Chapter 3, the transportation sector accounts for approximately a third of total emissions of CO2 in the United States, with a smaller fraction but a rapidly growing total in China. Combustion of oil, either as gasoline or diesel, is primarily responsible for the transportation- related emissions of both countries. Strategies to curtail overall emissions of CO2 must include plans for a major reduction in the use of oil in the transportation sector. This could be accomplished (1) by reducing demand for trans¬portation services; (2) by increasing the energy efficiency of the sector; or (3) by transitioning to an energy system less reliant on carbon- emitting sources of energy. Assuming continuing growth in the economies of both countries, option 1 is unlikely, certainly for China. Significant success has been achieved already in the United States under option 2, prompted by the application of increasingly more stringent corporate average fuel economy (CAFE) standards. And the technological advances achieved under this program are likely to find application in China and elsewhere, given the global nature of the automobile/ truck industry. The topic for discussion in this chapter is whether switching from oil to a plant- or animal- based fuel could contribute to a significant reduction in CO2 emissions from the transportation sector of either or both countries, indeed from the globe as a whole. The question is whether plant- based ethanol can substitute for gasoline and whether additional plant- and animal- derived products can cut back on demand for diesel. The related issue is whether this substitution can contribute at acceptable social and economic cost to a net reduction in overall CO2 emissions when account is taken of the entire lifecycle for production of the nonfossil alternatives. There is an extensive history to the use of ethanol as a motor fuel. Nicolas Otto, cred¬ited with the development of the internal combustion engine, used ethanol as the energy source for one of his early vehicle inventions in 1860. Henry Ford designed his first auto¬mobile, the quadricycle, to run on pure ethanol in 1896.

Small molecules consisting of light-, few-electron atoms were the first species beyond atoms to yield to quantum-mechanical methods. Similarly, crystals of small light-atom molecules have served as most useful test cases of charge density mapping. The small number of core electrons in first-row atoms enhances the relative contribution of valence electron scattering to the diffraction pattern. Early studies, done just after automated diffractometers became widely available, were concerned with molecular crystals such as uracil (Stewart and Jensen 1967), s-triazine (Coppens 1967), oxalic acid dihydrate (Coppens et al. 1969), decaborane (Dietrich and Scheringer 1978), fumaramic acid (Hirshfeld 1971), glycine (Almlof et al. 1973), and tetraphenylbutatriene (Berkovitch-Yellin and Leiserowitz 1976). While thermal motion is often pronounced in molecular crystals, advances in low-temperature data collection have done much to alleviate this disadvantage. In recent years, subliquid-nitrogen cooling techniques have been increasingly applied. Among the most interesting aspects of molecular crystals are the influence of intermolecular interactions on the electronic structure. Physically meaningful Coulombic parameters pertinent to a molecule in a condensed environment can be obtained from the diffraction analysis, and can be used in the modeling of macromolecules. The enhancement of the electrostatic moments relative to those of the isolated species has been noted in chapter 7. But, beyond these considerations, molecular crystals are important in their own right. For example, crystals of aromatic molecules substituted with π-electron donor and acceptor groups are among the most strongly nonlinear optical solids known, considerably exceeding the nonlinearity of inorganic crystals such as potassium titanyl phosphate (KTP); while mixed-valence organic components of low-dimensional solids can become superconducting at low temperatures. The relation between such properties of molecular crystals and their charge distribution provides a continuing impetus for further study. The suitability of light-atom crystals for charge density analysis can be understood in terms of the relative importance of core electron scattering. As the perturbation of the core electrons by the chemical environment is beyond the reach of practically all experimental studies, the frozen-core approximation is routinely used. It assumes the intensity of the core electron scattering to be invariable, while the valence scattering is affected by the chemical environment, as discussed in chapter 3.

Protic solvents have hydrogen bound directly to electronegative atoms, such as oxygen or nitrogen. They are characterized by their ability to form strong hydrogen bonds with suitable acceptors, particularly simple anions. They include alcohols, formamide and other primary and secondary amides, and formic acid. In methanol, dissociation constants of carboxylic acids, phenols, and protonated nitrogen bases show excellent correlations with corresponding values in water. The largest differences occur for carboxylic acids, which are typically 5 pK-units weaker than in water. Acids become increasingly weak in the higher alcohols, especially t-butanol, because of poorer ion solvation. Homohydrogen-bond formation is generally weak, but ion-pair formation becomes progressively stronger as the solvent polarity decreases. Formamide contains a polar carbonyl group in addition to the ability to hydrogen-bond to anions, and displays pKa-values close to those in water. Formic acid hydrogen-bonds strongly with anions, but poor solvation of the proton, which inhibits the dissociation of acids, normally prevails.

Tables of dissociation constants are given for a wide range of substrates in the most extensively studied non-aqueous solvents, including methanol, dimethylsulphoxide, dimethylformamide, acetonitrile, and tetrahydrofuran. Equations representing correlations among the solvents and with water are also included.