Dark Horse May Outdo Lithium-Ion Battery Storage

Leading battery storage technology developers and emerging market players, including Elon Musk's SolarCity and Tesla, are investing billions of dollars to improve the performance and lower the costs of manufacturing lithium-ion (Li-ion) batteries. Along the way, they are promoting Li-ion battery storage as a cleaner, more efficient, sustainable and significantly less costly solution across a wide range of applications, from electric vehicles, homes and buildings on up to grid-scale energy storage and stabilization.

But Li-ion isn't the only game in town when it comes to emerging advanced battery and energy storage technologies. And there are those who believe proponents are stretching their case too far in touting the advantages of Li-ion battery storage across such a broad range of applications.

Developers of flow batteries, for instance, say utilities and other large end-users would be ill-served by acquiring Li-ion battery storage, except for comparatively narrow and strictly defined cases. A developer of vanadium-flow battery storage systems, Imergy Power Systems, is taking its case to the market.

Flow batteries for utilities and large-scale end users

On Feb. 17, Fremont, California-based Imergy announced the introduction of its largest line of vanadium-flow batteries to date: the ESP 250 series. Capable of operating 20 years or more without the need to replace electrolytes and with only a couple of moving parts, Imergy's ESP 250s are capable of delivering 250 kilowatts of electrical power for four or more hours.

That's at least 1 million kilowatt-hours of electrical energy housed in two 40-foot shipping containers. It's an amount that – when considered alongside other salient attributes – makes ESP 250s ideal for utilities, large commercial, industrial and government end-users, and developers of renewable energy projects, Imergy states in a news release. Its ESP 250s, Imergy says, are ideal for use across a wide range of large-scale applications.

ESP 250s, for instance, are more efficient and will soon prove more cost-effective than the conventional natural-gas and coal-fired “peaker” plants used by grid operators to meet peak electricity demand. They are also much better-suited than Li-ion batteries for applications such as utility and grid operator transmission and distribution investment deferral, renewables management, microgrid implementation, emergency back-up power system delivery, frequency regulation, and peak shaving, Imergy contends.

Broad spectrum energy storage applications

Imergy CEO Bill Watkins touted the broad spectrum use of its vanadium-flow batteries across the supply and demand sides of U.S. power markets. “With the introduction of the ESP 250, Imergy has broadened its product portfolio to include a product for every major energy storage market segment and application,” he was quoted as saying.

“From demand response for individual buildings, to frequency regulation for the grid, Imergy has a product designed to meet the market’s growing demand for low-cost, high performance energy storage.”

Those assertions were echoed by company president and COO Tim Hennessy in a 3p interview. A combination of unique characteristics and attributes make Imergy's vanadium-flow battery storage systems ideal, and much better suited than conventional alternatives and Li-ion battery storage systems, for a wide range of stationary energy storage applications – from utility-scale down to residential-scale energy storage applications, Hennessy explained.

The advantages of vanadium-flow batteries start and flow from their unique chemistry. Added to that is the combination of high-density energy storage, unlimited use, 100-percent charge-discharge capacity, fast ramp-up, ramp-down and response capabilities, and their long life.

Vanadium's unique chemistry means that end-users never have to replace the electrolytes used to charge and discharge Imergy's flow batteries. Stored in separate containers connected to the electrolytic cells that store and deliver electrical energy means that Imergy's vanadium-flow battery systems are modular and can be scaled up or down quickly as needs require.

Significantly, its vanadium-flow batteries are safer and more reliable than Li-ion battery storage systems. They are nontoxic and can operated in complete safety across a much wider range of temperatures than Li-ion batteries, Hennessy noted. That means avoiding the risk of battery systems erupting in flames, a big problem that has plagued Li-ion battery systems.

In addition, Imergy obtains the vanadium used in all of its batteries from secondary sources, such as mining operations and steel production. By recycling vanadium, Imergy is realizing value and beneficial use from what would otherwise be industrial waste. Furthermore, end-users can recover all the vanadium used in the system at the end of its useful life, generating revenue by selling it secondary markets.

Low levelized cost of energy

All this results in a low levelized cost of energy (LCOE), a measure of the overall costs of energy production and storage solutions over their lifecycles, Hennessy emphasized.

According to a recent market research from Navigant, worldwide revenue from energy storage for grid and ancillary services is forecast to grow rapidly and reach $68.5 billion from 2014 through 2024. “Around the world, utilities are also studying storage as an option to manage peak demand and increase grid resiliency,” Imergy points out.

“These same utilities are also focused on storage as a way to manage the impact to the grid presented by the increasing penetration of intermittent renewable energy sources such as wind and photovoltaic. Utilities now recognize that long-duration energy storage is the key to solving these issues. Imergy’s ESP 250 offers a solution which is typically financially and technically impractical for other battery and storage chemistries.”

The key to Imergy's ESP 250 and smaller-scale ESP5 and ESP30 vanadium-flow battery systems, Hennessy added, is “that it's a integrated, 'plug-and-play' platform."

“Our smaller platforms can be aggregated, but we've done that with the 250. That allows end-users, and our company, to realize the benefits of economies of scale – both in terms of customer applications and lowering the costs of manufacturing.”

This is unique to vanadium-flow batteries and what Imergy is doing as a company, Hennessy continued. “No one has the ability to move so easily and go from one end [of the market] to the other,” he told 3p.

*Image credits: 1) Goodpix.com; 2), 3) Imergy Power Systems