Newton’s law of universal gravitation cannot be ignored. Many have tested, as of yet, none have defied said tenet. Physics reveals the force of a fall as equal to the mass of the dropping object, multiplied by the acceleration of gravity (a standard 9.80665 m/sec²). Normally we confront this force when we ascend stairs, step on a bathroom scale or do some pull ups. It generally is not a force most of us think about.
Hydroelectric dams are a common type of energy storage that uses gravities effect to generate large amounts of energy. The trouble with large reservoirs is the amount of real estate they encompass and the environmental impact flooding vast areas inflicts. Hydro systems referred to as pumped storage have a condensed footprint. They generate electricity when water flows from one reservoir at a higher elevation to a lower one. Using alternate energy such as wind or solar, the system pumps the water back up for reuse as electrical demand dictates.
Gravities potential for storing energy has piqued the interest of entrepreneurs in Switzerland without the dam consequences. Energy Vault is a company that uses recycled concrete blocks and a system of tower cranes as a gravitational battery. Using wind or solar energy as the driving force, their system lifts the slabs into position around the crane during times of minimal demand, lowering them again when electricity is needed by the grid.
Cost analysis indicates this type of energy storage is more economical per kilowatt hour capacity than the either Tesla’s lithium ion battery used in Australia or the Brine4power redox flow battery used in Germany; the two largest alternate energy storage batteries currently deployed. Energy Vault has designed a 35 MWh system that will be put into production for India’s Tata Power in 2019.
Gravity storage using towers is unique, its small footprint and the number of recycled materials providing the mass for energy generation makes it physically versatile. This simplicity of design, employing gravity, elevation, and weight, is available in the Alberta oil patch. Drive through any oilfield in the province and you will see the iconic nodding donkey pump jacks reciprocating a string of sucker rods in and out of a well bore. Drilling and service rigs by design, lift and lowering the massive weight of drilling or tubing strings daily.
With over 83,000 inactive wells in Alberta the potential for gravitational energy storage abounds. As of yet there is no indication any resident visionary has recognized this capability. As gas and oil-wells deplete into the unproductive category, repurposing their infrastructure for the storage of energy produced by the wind turbines or solar arrays gaining prevalence in the province, seems obvious.
At first glance, it would seem the Canadian petroleum industry has been demonized. The very industry that has provided smoke free skies, warmed homes, powered vehicles, or provided the main feedstock for manufacturing, is being credited as a source of innovation for the transition to next generation energy supply. Now that is regrettable.