Energy density is not an immutable requirement
This article in the Bulletin of the Atomic Scientists makes an important point: no energy storage mechanism is ever likely to approach the energy density of hydrocarbons like oil and coal, certainly not at scale.
Part of the reason coal and oil are enemies of the human race is precisely that they are so seductive — they really are fantastically designed energy carriers, with high energy density in easily portable packages. It will take incredible collective self-discipline to keep from using them up (and reaping the long-term consequences).
The conclusion, however, bugs the snot out of me:
The bottom line is that nature has given us hydrocarbons in the form of fossil carbon and biomass, and their energy-mass and energy-volume densities are superior to the thermodynamic limits of nearly all conceivable alternatives. Thus, it’s quite likely that hydrocarbons of one form or another will be humanity’s primary energy storage medium for quite a long time.
This is classic techno-head thinking, conceiving of sociocultural arrangements as fixed and technology as the only dynamic variable. If technology cannot displace hydrocarbons on a one-to-one basis, slotting some alternative neatly into the space hydrocarbons now occupy, well then, we just throw up our hands and keep trundling on toward climate catastrophe.
Energy density is a subspecies of centralization — centralization of power, of control, of resources. In all cases, there are alternatives to centralization: decentralization, dispersion, democracy, many-to-many coordination rather than one-to-many top-down control. In many cases the alternatives are preferable — more resilient, more equitable, and more empowering.
There’s no reason we can’t change our sociocultural practices to have a perfectly prosperous, healthy, enjoyable life without highly dense (and dangerous) energy carriers. Energy won’t be concentrated in a few places — coal trucks, central power plants, oil wells — but carried in less dense form in thousands of places like plug-in hybrid batteries and the walls of passive-solar homes. We’ll change our settlement patterns and building practices to require less energy so that less dense energy sources like solar and wind suffice. We can replace brute power with intelligence.
Technology is only one piece of the puzzle; its limits are not our limits. We’ve got to change how we think about and interact with energy on a holistic, systems basis.