New Storage Technologies for Renewable Energy

Electric storage batteries based on zinc instead of lithium are now in widespread usage around the world, even though their existence is poorly recognized.  A report in the New York Times describes a zinc-air battery produced by the company NantEnergy.  The company received development grants of US$5 million from the U.S. Department of Energy.  It has already deployed its batteries in Asian and African villages, and in cell towers in the U.S., Latin America and Southeast Asia.  Its founder, Dr. Patrick Soon-Shiong, stated that 110 villages have established local microgrid systems, using electricity generated on site by solar arrays.  Dr. Soon-Shiong anticipates that use of the batteries will expand greatly in telecommunication towers, and expects use to spread to home energy storage and electric vehicles as well.  He foresees a potential market of US$50 billion.

The zinc battery has several advantages over lithium-based batteries.  Zinc has a high abundance in the earth, and is already heavily mined and used in many applications; its ore also includes other metals that are profitably extracted.  Its annual production rate is projected to reach a maximum between 2020 and 2030, with a high projected cumulative production tonnage being possible.  Zinc batteries cost about US$100 per kilowatt-hour of stored electrical energy, whereas lithium batteries cost in the range of US$300-400 per kilowatt-hour, according to the New York Times report.  Elon Musk, the head of Tesla, believes he can get the price down to the same level as the zinc battery.  Lithium likewise is abundantly found around the world, but active lithium mining is limited to a few countries, constraining its price to high values.  Its main demand is limited to batteries for fixed and vehicular electric storage.

An important advantage for zinc is that its batteries contain water-based electrolyte fluids, which are not flammable.  Lithium batteries, in contrast, operate using flammable solvent-based electrolyte solutions.  This is the reason that lithium batteries have been known to ignite and burn, sometimes spontaneously.

Recently an ambitious plan was announced for Hoover Dam on the Colorado River, reported in the New York Times.  The dam, 726 feet high and harboring 17 huge electricity generators that supply power to Los Angeles and much of southern California, holds back a large lake created from the river.  One way of storing electricity is to pump water from a low elevation back up to a higher one, so that the pumped water can be used to generate new electricity on demand.  In the Hoover Dam proposal, massive pipes further downriver from the outflow from the dam and generators would capture some of the water and pump it back up to the reservoir lake behind the dam.  The electricity to drive the pumps would come from renewable sources, solar and wind energy.  Currently the project is expected to provide electricity from the stored water at about 20% higher than current electricity rates, but for 40% less than provided by commercial scale solar electricity, according to the report.  The project’s cost is estimated at US$3 billion.

Analysis

The United Nations-sponsored Paris climate agreement of December 2015 set the goal of keeping Earth’s projected increase in long-term average temperature to less than 2°C (3.6°F) above pre-industrial times by the end of this century.  It also set a preferred more ambitious goal of keeping that temperature increase to less than 1.5°C (2.7°F). 

In order to contribute to achieving these global objectives, many cities in the U.S. have established voluntary or statutory objectives of reducing the annual emission rate of all greenhouse gases to near zero as soon as possible; many cities seek to accomplish this by midcentury.  The movement to adopting these policies has become more urgent since federal policy in the U.S. has actually regressed in the last two years.  The government is actually undoing previously implemented regulations limiting emission rates in electricity generation and passenger vehicles.  That backtracking increases the greenhouse gas emission rate in the U.S.

As noted, the municipal policies strive to reduce annual emission rates to near zero.  This means that electricity must be provided essentially completely from renewable sources, that cars and trucks be powered by electric batteries or by hydrogen fuel cells, and that space heating and cooling in the built environment be provided exclusively by electric-powered heat pumps.  This migration away from coal, natural gas, diesel, fuel oil and gasoline (fossil fuels) will increase the demand for renewable electricity by 2-3 times its present level.

This is the reason that new technologies such as zinc-air batteries and pumped water storage acquire such high significance going forward.  The coming changes in our energy economy will be challenging; indeed they are nothing short of revolutionary.  The unequivocal needs for these changes will provide broad new business opportunities and new jobs for American workers.

© 2018 Henry Auer