Redflow’s innovative application of flow battery technology for telecoms infrastructure shows great potential

TowerXchange caught up with Simon Hackett, Chairman of Redflow Limited and a champion of a innovative new commercial application of zinc-bromide flow batteries. Redflow’s ZBM battery is a good fit for emerging market telecoms. The ZBM supports a ten+ year lifespan of daily cycles that is insensitive to depth-of-discharge. It can be fully charged and totally discharged every cycle without damage. Accordingly - and unlike other battery types - 100% of the battery capacity can be utilised to supply energy to a telecommunications load without needing to ‘oversize’ the battery capacity (as is required with other battery chemistries). Zinc - bromide batteries have generally been considered too large and high capacity for deployment on telecoms sites to date, but Redflow are in the process of changing this.

TowerXchange: Please give us an introduction to your company.

Our Head office and research and development centre is in Brisbane, Australia. Our global presence also incorporates offices in the USA and Europe. Our batteries are manufactured by Flextronics in North America to be sold to the world market. This network provides us with the capacity to sell, integrate and maintain our products internationally. Our batteries are already installed in a range of industries, including telecommunications, agriculture and power distribution, in Australia, Central America, Asia and Africa.

TowerXchange: Tell us about your solution and where it fits in the telecom tower ecosystem.

Redflow has spent the last decade designing and perfecting the world’s smallest flow battery. Most people in the telecoms industry are familiar with the other batteries more commonly associated with tower sites such as lead acid or lithium-ion. Redflow’s ZBM is the first flow battery product that is the right physical size and capacity to serve the needs of the tower ecosystem.  The ZBM module has an 8kWh or 10kWh storage capacity, supplying 48 Volts DC at 60-70A typical (120A Max) per module. Multiple modules can be clustered to develop any required energy storage size.  This means the ZBM is the first flow battery that can scale up to a 600 kwh shipping-container form-factor module (60 ZBM’s), and that can scale down to 10-20kWh (1-2 ZBM’s) for telecoms towers, small commercial and residential applications.

TowerXchange: Please tell us about your partners and global footprint.

We work with energy integration providers such as Emerson, Blue Sky Energy and Jaladri (amongst others).  We currently have ongoing trials on tower sites in several markets including Australia, Central America, Asia and Africa, giving us an opportunity to build on our operational experience globally. These trials are progressing well and now we’re sitting on the cusp of some large scale deployments.

TowerXchange: Batteries are typically deployed in remote sites in developing markets. What are the specific benefits of flow batteries in these environments?

Flow batteries are particularly suited to use in remote areas where the grid is unreliable. They will perform well over a very long lifetime in harsh conditions and will and suffer no damage if completely depleted. By contrast, lead acid batteries can be damaged or suffer reduced operating life if they are allowed to become fully depleted or if they are disconnected for a long period.

Zinc-bromide flow batteries are able to work in a wide range of ambient temperatures, from five degrees Celsius ambient up to forty five degrees, which is a major benefit in more hostile climates. The battery will self-protect outside of these temperature limits to avoid damage.

The ZBM is well suited to hybrid solar solutions and it is also a good fit for generator run-time-reduction applications.

A unique capability of the ZBM is an ability to be completely shut down (and taken offline) at any state of charge (including fully charged), for an arbitrary period without loss of internally stored energy. The battery can be brought back online later with the application of a very small external power source for less than 30 seconds. This provides an outcome much like a diesel generator, but with indefinite standby time, no physical maintenance requirement, and no issues with the long term storage of diesel fuel.

TowerXchange: What kind of life span do flow batteries have?

Redflow ZBM batteries have a warranted ten year life span based on daily full cycles (and insensitive to cycle depth variation). A 10 kWh ZBM battery can store and recover up to 36,000 kWh over this period. Lithium-ion battery lifespan (by comparison) is a complex function of charge cycle depth and charge cycle energy intensity, with significant ‘reserved capacity’ being needed to avoid the potential for battery pack damage. The lifetime of the ZBM is independent of cycle depth and cycle intensity and are not damaged by full-charge or full-discharge events, even if they occur every single day.

TowerXchange: Are there any other key differentiators between flow batteries and other types of batteries used on tower sites?

Flow batteries are real workhorses; the are hardy and will run consistently, require less maintenance, with the on-board control system providing proactive battery management and protection. They’re safer too as the electrolyte is actually a fire retardant. The majority of the battery (even the electrode stack) is made of fully recyclable plastic.

TowerXchange: Do you envision any other applications for these batteries in the future?

Currently our primary telecoms/ICT focus is telecom tower sites as our battery is an ideal energy storage solution for that market. They can also be deployed in data centre applications, as well as other non-telco power support roles (such as water pumping stations in weak-grid or no-grid environments). We have seen increasing interest in deployment of these batteries in residential environments, and we expect to have a residential reference energy system design available to system integrators in the first quarter of 2016.