Battery against Battery

 By Andrew Burger

Lithium-ion batteries dominate the fledgling, fast moving market for stationary battery-based energy storage systems (BESS). Li-ion BESS accounted for no less than 96% of newly installed capacity in the U.S. in 2015, a year in which total installed capacity soared 243% year-over-year. Li-ion isn’t the only option on the market for medium- and large-scale battery energy storage technology, however. A new generation of redox (reduction-oxidation) flow batteries asserts their products are much better suited for medium- and large-scale applications where heavy use, long-term cycling, durability and safety are paramount, such as on campuses, for community service, on commercial and industrial sites, and on utility grids…

(Cover photo by

Lithium-ion batteries dominate the fledgling, fast moving market for stationary battery-based energy storage systems (BESS). Li-ion BESS accounted for no less than 96% of new installations in the U.S. in 2015, a year in which total installed capacity soared 243% year-over-year, according to the to Energy Storage Association-GTM Research’s ¨U.S. Energy Storage Monitor: 2015 Year in Review

Li-ion technology isn’t the only option on the stationary BESS market, however. Moreover, Li-ion systems aren’t the best choice when it comes to core market segments and use cases, developers of a new generation of redox (reduction-oxidation) flow batteries contend.

They assert their redox flow batteries are not only safer, more versatile and better performing than Li-ion technologies, but less expensive from the perspective of total life cycle costs.

Redox Flow Battery Fundamentals

Systems providers contend redox flow battery technology is much better suited for medium- and large-scale applications where heavy use, long-term cycling, high energy output, durability and safety are paramount. These include: primary, secondary and emergency grid dispatch and ancillary services, as well as similar applications on campuses, commercial and industrial sites, in remote areas and across cities.

“Flow batteries allow you to separate the power and the energy, so if you want more power, you just add more stacks,” Imergy Power Systems´CEO Tim Hennessy explained in an interview. ¨If you want more energy, you just add more liquid into the tank, a bit like adding petrol to a fuel tank in a car in a sense.¨

The ability to go through thousands of full charge-discharge cycles is the key to redox flow batteries’ low Levelized Cost of Energy (LCOE), explained Gildemeister Energy Storage Solutions’ Matthew Clarke. End-users “can still expect a 20-year lifespan” even given such heavy, long-term use, he was quoted in an industry news update.

Flow Battery Market Prospects

Stationary Li-ion battery manufacturers benefit substantially from the technology’s widespread use and global manufacturing base. Aiming to compete, flow battery manufacturers have been raising capital in a bid to ramp up manufacturing volumes and bring system costs down to $200 per kilowatt-hour (kWh).

Israel’s Electric Fuel Energy, a subsidiary of U.S.-based Arotech, says it’s nearly there (in the $250-$300/kWh range) with its new Iron Flow BESS technology, even at low manufacturing volumes.That said, system prices in general remain high, and the costs of permitting, logistics, installation, operations and maintenance add significantly to the total. That’s led flow battery manufacturers to focus initally on markets where access to grid power is lacking, unaffordable and/or unreliable – islands, rural communities, and isolated commercial and industrial facilities, such as mining operations and wireless telecoms towers.

In a December 2014 report, Lux Research forecast falling costs would fuel growth in global installed capacity to 360 MWh and revenue to $190 million in 2020.

The Importance of Assessing Full Life Cycle Costs

Zinc-iron flow battery systems are now coming off the production line at VizN’s new manufacturing plant, the result of a contract manufacturing partnership the company struck up with Jabil Circuit, Inc. in mid-2015. VizN is experiencing greater than expected demand across its three main customer categories – commercial and industrial (C&I), microgrid and utility – as well as geographically, CEO Ron Van Dell said in an interview.

¨We have roughly 100 MW of committed business under contract that we need to ship over the next 12 months…It’s a pretty steep ramp for us and Jabil, especially considering 2015 was really our first year in the market.¨

Market participants are increasingly recognizing the degree and extent to which the versatility, safety and thermal management characteristics of VizN’s zinc-iron flow batteries enhance the BESS value proposition, Van Dell elaborated.

Safety and Thermal Management at the Grid Edge

VizN’s flow batteries are much safer than competing Li-ion systems, which gives them an advantage where most of the action is, he pointed out. ¨If you look at where customers are getting more value from a system, its towards the grid edge – not individual homes, but they want to get out there to the substation level and provide for community-type needs and be able to integrate distributed solar generation and meet resiliency targets…

¨When you’re closer to where people live and work, safety matters. In contrast, ¨Li-ion requires a lot of added cost to be what I would call ‘marginally safe.’¨

Thermal management is another advantage of VizN’s flow battery technology. ¨There’s a lot of added cost and complexity [associated with Li-ion systems],¨ Van Dell explained. ¨You’re trying to limit instantaneous peak temperatures at every individual cell, and there can be tens of thousands of cells.

¨That requires a sophisticated cooling system that can be more complex than the underlying storage system itself.¨ In contrast, customers only need to monitor and manage average temperatures for the entire system over 24-hour periods with VizN’s technology, he noted.


SEE MORE: BESS practice on energy storage by Andrew Burger



Busting Li-ion Myths

¨People talk about how inherently low-cost lithium systems are going to be. Frankly, I see a lot of mythology around that,¨ Van Dell continued. ¨First, the right variant of battery storage best suited for transportation is not the same as that for large-scale stationary storage, so there’s no real synergy.¨

Furthermore, there’s a strong tendency in the marketplace ¨to confuse overall life cycle cost with the cost of lithium-ion cells, which make up only 30-40% of total costs.¨ As a result, ongoing declines in the cost of Li-ion cells ¨are just going to move the needle on overall system costs 10 or 15 points.¨

More broadly speaking, ¨the paradigm that’s getting blown up right now is the idea that you want to create a one-for-one, singular match between a particular application and a particular battery technology — Li-ion for frequency regulation on PJM’s Mid-Atlantic regional grid, for example.”

¨It begs the question of the need for multiple services that can support additional revenue streams that in turn enhance investment returns, integrate an uncertain mix of generation assets at particular interconnection points, and meet new policy requirements, Van Dell said.

He continued: ¨The question then becomes, ‘How do you future-proof your investment and not wind up with a ‘one-trick pony.’ There’s more uncertainty in the real world when it comes to future needs.¨ Prospective customers ¨are more likely to need multiple services and meet multiple new policy requirements at the same time. A full-service platform responds better as conditions change, and that’s what we’re focusing on.”

about the author
Andrew Burger
Andrew Burger has been reporting on energy, technology, political economy, climate and the environment for a variety of online media properties for over five years.