Technology for Luddites
“Forget batteries with complex chemistries or precision-tuned flywheels. A growing number of energy storage start-ups are promoting the idea that the most economical, most expedient ways to store power revolve around harnessing the four elements of the ancient world: earth, air, water and fire.”
Read more: The most important man in energy storage? Try Archimedes.
“Out in the Bodie mining district, California, they have a peculiar motor in use. It is called an arastra, and consists of an overshot wheel operated by sand instead of water. A windmill runs a belt containing buckets, which carry the sand up to a big tank, just as grain elevators carry wheat in a flouring mill. A stream of sand is let out upon the overshot wheel and it revolves just as it would under the weight of a stream of water. The arastras move steadily at their work. When there is much wind, sand is stored up for use when calm weather prevails, so the arastras are never idle. It is perhaps needless to say that the sand is used because water is scarce. The arastra is an invention of a miner named Townsend.”
Quoted from: The Manufacturer and Builder, Volume 0016 Issue 2 (February 1884).
The GravityLight uses a sack of sand or stones to gradually pull a piece of rope through a dynamo mechanism which generates electricity to power an LED. It is a cheaper and more sustainable option than a solar powered light, which requires not only a solar panel but also a battery. The product is aimed at the developing world and its makers raised 400,000 dollars at indiegogo.
The technology could be further improved by including pulley mechanisms that were used to operate human powered cranes and lifting devices in pre-industrial times. This would allow a person to lift heavier weights and thus power more powerful lights.
To be precise, the light is not powered by gravity. It is muscle-powered, while gravity stores the energy and fulfills the role of a battery. Hat tip to Bernd Vleugels.
“Energy storage becomes more important as we transition away from fossil fuels—already its own energy storage medium—to more intermittent sources. But besides batteries—which offer a limited number of cycles and for some types require monthly maintenance—what other non-fossil in-home energy storage alternatives might we consider, and how much energy might we expect to store in each case? We will look at gravitational storage, flywheels, compressed air, and hydrogen fuel cells as possible options. Some might even cost less than $100,000 to implement in your home.” Read more.
“Putting the pieces together, our national battery occupies a volume of 4.4 billion cubic meters, equivalent to a cube 1.6 km (one mile) on a side. The size in itself is not a problem: we’d naturally break up the battery and distribute it around the country. This battery would demand 5 trillion kg (5 billion tons) of lead. A USGS report from 2011 reports 80 million tons (Mt) of lead in known reserves worldwide, with 7 Mt in the U.S. A note in the report indicates that the recent demonstration of lead associated with zinc, silver, and copper deposits places the estimated (undiscovered) lead resources of the world at 1.5 billion tons. That’s still not enough to build the battery for the U.S. alone. But even then, we aren’t done: batteries are good for only so many cycles (roughly 1000, depending on depth of discharge), so the national battery would require a rotating service schedule to recycle each part once every 5 years or so. This servicing would be a massive, expensive, and never-ending undertaking.” Read more: A Nation-Size Battery.
