This is an issue I've considered from many angles for a long time. I'm not an expert and can't say I have all the answers but some things to consider:
1) Everything is a representation of light, i.e. in theory, we're already using light's derivative (e.g. fossil fuels).
We go through locating, extracting, processing, distributing (with countless other bureaucratic steps) to unleash the energy. All of those added steps inflates the volume, but is still fundamentally backed by the release of electrons and photons.
Still, the very act of processing dilutes the value (while creating what are virtual temporary jobs, wealth, and industry). The value must then be recovered by the Consumer converting the stored energy back into kinetic energy and uses it in whatever way.
It's the Foundation upon which the Global Economy is based but very inefficient. Most of the stored energy is lost during the Processes, literally eliminating the value of the commodity!
2) The Value, then, of light is intrinsic, i.e. utilitarian. "Scarcity" is achieved through access to energy collection, distribution, and conversion.
3) An interim economy (which could last 50-100 years!) is created through the gradual transition from a carbon based to renewable energy economy.
I've used solar as the example because it is essentially limitless. Furthermore, wireless transmission from space reduces distribution cost immeasurably.
Still, I see that as the eventual goal (like a fusion reactor) and will require enormous capital expenditures and international cooperation.
Until then, we must rely upon alternative sources to supplement when the Sun isn't shining or the Wind isn't blowing. Geothermal and wave produced energy are great but also require tremendous investment and are not as readily available, especially in the heartland.
I've no doubt we will figure it out but, until then, our partian dependence on fossil fuels will remain which, imho, is not altogether bad. We'll always need the derivatives of petrol conversion, such as oils and plastics, but more importantly they are a back up plan.
In case some unforeseen catastrophe occurs, such as the Sun stops shining, the Moon disappears taking the tides with it, the atmospheric reaches a steady pressure elimination wind, gravity ceases causing water to sit still. Sounds like a movie, huh? Nearly impossible but still good to have a back up plan.
4) The biggest problem (and threat) exists in people's greed and short sightedness. Theoretically, improving the efficiency of harnessing renewable energies would increase the value of the "Joule" (hypothetical unit of energy currency) while expanding its use creates a natural expansion of the currency's supply.
Furthermore, without being able to actually use such energy is negligible without a concerted effort to produce new technologies for every aspect of life! Such a reality creates an opportunity for new and existing companies to transition from carbon based to renewable. Other promising sources, like compressed and liquid natural gas, can serve as a transition fuel from carbon based to renewables.
Improving the efficiency and availability of renewable energies are incentives to continue exploring and improving upon technologies. Unfortunately, there are many who would work vehemently to slow and event prevent such innovations from taking place.
Yet, demand will necessitate supply which is totally opposite the Supply Side Economics of the past three (plus) decades. Many point out that it takes petrol based technologies to produce the means of utilizing renewable energies. That is true but that is a one time (or limited) is investment. No doubt the kerosene lantern was developed to candle light. As it should be-technologies lead to their eventual replacement.
Many also complain about the tax credits and incentives put in place to help make renewables viable. Yet, they conveniently forget that it was, and remains to be, such favorable taxation that has allowed the carbon based economy to flourish!
I fear, until our entire monetary system collapses, cronyism will prevent the natural transition from one source of energy to another. That is all about power: power corrupts and absolute power corrupts absolutely.
Still, there are more wireless devices than there are people in the World and, once satellites beam internet service to every inch of the Earth's Surface, every person on earth with a wireless device in hand will become a consumer.
Of course, it requires easy access to obtain information, awareness of one's freedom, and the Liberty to act upon one's will to be truly free. Consumption requires production, distribution, and maintenance and, if the Free Market is allowed to function properly-as a reflection of people's Free Will-it seems practically inevitable that an energy based currency becomes the Global Standard in the Next Century.
Such a commodity based currency, based upon renewable energy, holds the potential to unite people as never before and be the Greatest Innovation in the History of Mankind after fire. Like fire, it has near perfect application, near limitless scale, and immeasurable benefits for every person in every country. It will allow us to address the shortages in the World and is our means to reaching other planets and beyond our solar system.
The only Question is if "The Power of the Joule" will rest in the hands of All, or in those of only a few. The Answer will be one we all decide together.