We don't have to go back very far (or better put we could back thousands of years) to find some pretty high-tech/low-tech solutions to our energy problems. We have this image of people living in caves and scratching in the dirt to eek out an existence, but that image couldn't be further from the truth.
With regard to technology, we're not as advanced as we like to think. A battery-like contraption was found in an achealogical dig of a 2000 year old village in Baghdad. With regard to a knowledge of the natural world and how it works, we are as dim as a candle by comparison. Many ancient cultures had an intimate relationship with the sun and knew how to use it for heating and cooling and lighting, even cooking and preserving food - things we think are so innovative these days. They also knew how to time their plantings with nature so that there was less of a loss, and they knew how to use the resources around them, in their local area, to live a comfortable and sustainable life, having an intimate knowledge of both edible and medicinal plants from which our modern pharmacology is derived, but which even the developers of many of our modern drugs simply don't know or understand.
The ancients also had some pretty cool gadgets ... like the Samovar, which is a metal container used to boil water for making tea. According to the linked wikipedia article, a 1989 archealogical dig found a samovar that's believed to be over three thousand years old.
Modern samovars are usually electric, but traditionally, the water was boiled using coal or charcoal, and since the device was designed to make tea, there was often a resevoir on top to hold the tea. They sound similar to our teapots or perhaps one of those coffee percolators, but they are so very different. The difference is in the design, and the samovar is actually a beautiful, intricately designed piece of functional art.
And that would be where the key difference between our modern society and ancient cultures lies. We like to think that we're more advanced, and if by advanced, we mean that we can be almost completely sedentary while machines do all of the work, then I would agree, but if we mean that we are smarter or more creative, then I would have to staunchly disagree. Ancient socieities were rife with incredibly impressive beauty and art and culture, and feats of engineering that make our modern attempts seem rather sad by comparison. Further, they gave us knowledge of our world that has not been proved false over the centuries. The Roman aqueduct system, for instance, is the model for our modern sewer system. In thousands of years, we haven't found a better way than the Romans developed in the 312 B.C.
We would do well to look to those cultures for two reasons: to figure out why they failed and not repeat those mistakes (and it may be too late for that now); and to understand how they managed to survive ... and "thrive" ... without the massive inputs of energy that we rely on today.
As for me, someone on freecycle has offered a "Russian samovar", and I'm thinking I might ask for it. The only hitch is that it's a European device designed for a different electrical system (220 as opposed to 110), and it has a "funny plug." If I wanted to actually use it, I'd need to get someone who is an electrical engineer to make some changes ;).
I wonder if I know anyone like that ... hmmm ....