The way you use it is probably not really what change in terms of energy. Different energy sources can be more or less efficient though. But if you could store energy perfectly intact and with 100% efficiency in a battery the use of it will not change.
The price on the other hand is a matter of supply and demand. If supply is higher than demand the price is low etc...
The thing that mostly prevent us from producing more stuff or more energy heavy stuff is the availability of cheap energy and the price for the finished goods, it is rather simple. It's not like we need people to produce the stuff... access to cheap enough energy will prevent production of certain items for the price the consumers are able to pay for it.
So basically... of we had more easily obtainable energy we could do so much more, the amount of people are almost inconsequential. This goes for recycling materials too.
Great point. This is what's getting overlooked here. Commenters like
@Chthon are confusing intrinsic value with trade value, or "utility" vs. "value."
Intrinsic value is the value of a commodity when used or consumed. As noted above, 1 MJ when put into the right machine might get me 1 Amount of Work. Or a loaf of bread, when eaten, sates a certain amount of hunger. This is its utility.
That's different from trade value, which is how much someone will give you in exchange for the asset when negotiating. This is the asset's value.
Intrinsic value/utility depends on you, your needs and your ability to use a commodity. Trade value depends on you, your trading partner, and supply and demand.
As you say, "more easily obtainable energy" is essentially another way of saying "cheap energy." For a post-peak fossil fuel economy, energy would be in extremely short supply and therefore would have a lot of trade value. For a civilization with a dyson sphere, energy would be near-limitless and therefore all but valueless.
Returning to
@Chthon's formulation, in both cases 1 MJ will do 1 Amount of Work. However in our oil crisis the ability to do 1 Amount of Work is much more rare, and so has much more value (making it more expensive). Someone will trade a lot for that 1 MJ. In the latter case if someone asks a lot for 1 MJ you can just go buy it somewhere else, because megajoules are common and therefore cheap. Value has fluctuated wildly even though utility has remained constant.
Or take our loaf of bread. It will always sate the same amount of hunger, but someone starving will trade much more for it than someone who has recently eaten. Or someone in a desert compared to someone standing next to fifteen bakeries. It's because, again, value is situational even while utility remains fixed.
Or, as a final example, we know that energy prices aren't stable because we see that in the real world. Oil is a main 21st Century energy market and prices fluctuate every day. The price of a barrel of oil can skitter anywhere from $25 to over $100. That's value changing by 400 percent, even though the utility of that oil has remained relatively fixed.
Heck, let's strip out the middleman. The price of an
actual kilowatt hour changes all the time. This isn't even stored energy, it's the actual electricity itself. Just in the United States it can range from 8 cents to 33 cents on average depending on where and when you buy it. My lights don't glow any brighter, my waffles don't toast any crisper, but my energy might cost a lot more because of pure supply and demand.
