167: Geomechanical pumped Storage


In the desperate search to find oil and gas, fracking is the process of injecting liquid at high pressure into subterranean rocks, boreholes, etc. so as to force open existing fissures. Fracking not also increases the potential for oil spills, which can harm the soil and surrounding vegetation but can cause earthquakes due to the high pressure used to extract oil and gas from rock and the storage of excess wastewater on site.


Geomechanical pumped storage employs no chemical, does not trigger seismic activity and does not produce pollutants that require disposal and clean-up.

Aaron H. Mandell obtained a BSc and an MSc in environmental engineering from the from the University of Vermont, where he focused on numerical modeling and groundwater hydrology, continuing to work in the energy and water industries, establishing a succession of 4 start-ups. The limitation of pumped hydro electricity storage is that because it is dependent on mountains, lakes, or pre-existing underground caverns, it had not been widely implemented.

But in 2012 Mandell and petroleum engineer Howard K. Schmidt innovated a different approach: hydraulic geofracture energy storage system with desalinization or geomechanical pumped storage.

Energy is stored by injecting fluid at 600 lb psi into a hydraulic fracture in the earth and producing the fluid back while recovering power and/or desalinating water. When the pressurized water is released, it acts like a spring as it races through a turbine-generator above ground, powering it to produce electricity.

Electricity generated by renewables is used to compress and pump water underground, when demand is low and power is cheap. That pressurized water is released when new generation cannot match high demand, at night when the sun is not shining, or when the wind is not blowing.

The hydraulic fracture may be formed and treated with resin so as to limit fluid loss and to increase propagation pressure. The fluid may be water containing a dissolved salt or fresh water and a portion or all of the water may be desalinated using pressure in the water when it is produced.

Particularly adapted to storage of large amounts of energy such as in grid-scale electric energy systems, the technology could reduce the cost of most advanced batteries by 90 %.

In 2015 Mandell and Schmidt and set up Quidnet Energy and built a small-scale prototype at an abandoned natural gas well in in Erath County, about 80 mi. (130 km) west of Fort Worth, where the fledgling company has leased a 5,000 ft (1,500 m.) – deep well.

The test well held 5,000 barrels of water (about 215,000 gallons – 814,000 liters) and was designed to charge and discharge in blocks of four to eight hours.

Encouraged by the results, Quidnet ran another larger-scale pilot project, this time at an old geothermal well at the Blue Mountain Geothermal Area in northern Nevada.

The well was 14 in. (36 cm.) in diameter, larger than a typical oil and gas well, making it possible to inject a higher volume of water โ€“ and generating more power faster โ€“ at any time. The reservoir can hold up to 85k barrels of water, and produce 10 hours of electricity following a 14-hour charge.

In 2018, Quidnet received US$6.4 million in investment from Breakthrough Energy Ventures, itself backed by high-profile billionaires including Microsoft co-founder Bill Gates, Amazon founder Jeff Bezos, Virgin Group founder Richard Branson, Facebook founder Mark Zuckerberg and Alibaba co-founder Jack Ma.

Discover Solution 168: Geothermal energy

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