ABSTRACT
Many of the techniques used for larger-scale energy storage can, in a suitably modified form, also be used in small units and for dispersed application. For example, metal or composite material containers can be used to store liquid and gaseous fuels (rather than the excavated underground stores described in Chapter 9). Flywheels have, over the past century, had small-scale applications for smoothing the operations of motors or engines at rotational speeds lower than that of the underground devices currently considered with the use of advanced materials (Koohi-Kamali et al. 2013). Heat stores based on heat capacity or phase-change energy are used in relatively small-scale contexts, and batteries are used on any scale from nail-head size to utility storage banks. If hydrogen makes it into the future transportation sector, then safe hydrogen containers for automotive applications may be furnished by high-strength composite materials, probably a more likely solution than liquefied hydrogen stores (which lose energy when stored for several days). Figures 10.1 and 10.2 show examples of hydrogen-storage placement in recent prototype hydrogen vehicles. For consumer cars, the new equipment will be encapsulated and hidden under the floor (Figure 10.2) or elsewhere, and the car will be difficult to distinguish from a gasoline or diesel cousin.
