Gravity Batteries

Gravity Batteries

(C) Eric R. Pianka

Grandfather clocks are powered by gravity. Pulling the weight up provides power that is generated over a much longer time period as it slowly falls.

The great Dr. Jay Wright Forrester, a professor at MIT, grew up in rural Nebraska. While he was still in high school, Forrester rigged up a wind powered 12-volt DC electrical system using a windmill and an automobile generator. Essentially, the wind turned the generator. But, what to do when the wind didn't blow? Inspired by a grandfather clock, Forrester came up with a solution: when the wind DID blow, it lifted a heavy weight, then when it was calm, the weight fell by gravity turning the generator and switching polarity. Dr. Forrester invented "system dynamics" and won the Institute of Electrical and Electronics Engineers Medal of Honor in 1972.

One of the big problems with wind power is its intermitancy. Electricity is difficult to store. Battery technology has been slow and is both inefficient and limited. We could exploit grandfather clock technology on a massive scale to store excess energy during times of plenty for use later when electricity is needed, as follows:

Energy could be stored by laying rails going down on a hillside -- when excess energy is available, use it to pull up something heavy like an old locomotive. When the wind stops blowing it would turn over a DC generator as it fell back down. These giant "gravity batteries" wouldn't even have to be close to the wind turbines but could be many miles away. This same mechanism has been used to pump water uphill during periods of excess wind energy, which is then reclaimed later as hydroelectric power.

We need to convince people, especially politicians, of the importance of being proactive and using the last of our diminishing oil reserves to invest in infrastructure, especially electricity grids and railways. We should also develop and install green technologies, such as solar water heating systems as well as photovoltaic and wind turbine driven electrical generating plants as described above.

13 January 2010 by Eric R. Pianka