“Imagination is everything. It is the preview of life’s coming attractions.” – Albert Einstein

Vanadium redox flow batteries


TAM ENERGY is proud of its association and partnership with Wattjoule in Massachusetts, USA, and has secured a license agreement (Africa & Europe) for the manufacturing of Vanadium Redox Flow Batteries in South Africa.

TAM Energy is in the process of establishing its VRFB (Vanadium Redox Flow Battery) manufacturing facilities at the Highveld Industrial Park in Emalahleni, Mpumalanga Province – South Africa. The first batteries will be manufactured in the first quarter of 2021 after commissioning the factory.

The following technical data briefly deals with our technologies and competitive benefits, and why we believe our technology is the best in the industry. For more information, please don’t hesitate to contact me directly:

Lodewyk Bronn
Mobile: +27 (0) 74 068 2827
Office: +27 (0) 12 996 3010
Email: lodewyk@tamholdings.co.za
Technical Director

How it works

Wattjoule (TAM Strategic Partner) is a registered manufacturer with Vanitec

Powered by:


In a typical battery that most people are familiar with, both the power-producing and energy-storage elements are contained in a single physical package. In a redox flow battery, the power and energy storage elements are physically separate and decoupled. This construction provides for a maximum degree of system design flexibility and scalability not available in conventional batteries. The electroactive materials that store electrical energy are dissolved in a supporting liquid and the complete solution is called an electrolyte. The electrolytes are contained in tanks external to the means of energy conversion, and the amount of energy stored is proportional to the amount of electrolyte contained in the tanks.

Basic Redox Flow Battery System Operation

Basic Redox Flow Battery System Operation

Electrical power is produced in an electrochemical device called a redox flow cell as shown in the figure above. This flow cell can either produce electrical energy or absorb it, as electrons are transferred from current collectors to or from the dissolved active materials in the electrolytes. Arrays of these cells are built into a stack to produce a more usable quantity of power. This stacked array of cells is also referred to as an energy converter stack since it is converting electrical energy to electrochemical energy and vice versa. More power requires a larger energy converter; more energy requires more electrolyte. This power and energy independence, provided only by a flow battery system, allows electrical engineers to cost-effectively size both the power and energy capabilities of any system to virtually any stationary energy-storage application. This means flow battery systems can service a much broader range of applications than any other stationary energy storage solution, even lithium-ion based systems.

To start a typical charge/discharge cycle let’s begin by charging the system. To do this, we pump discharged electrolytes through the energy converter while external electrical power is applied in a controlled manner, and the electrolytes charge, thereby storing electrical energy. We stop pumping when we sense the system is fully charged or when there is no electricity available for storage.

The next part of the cycle is discharge. To do this, we now pump the charged electrolytes from the external tanks through the energy converter, electrons from the negative electrode flow through an external circuit to the positive electrode, and electrical power is now generated to power an external load. Thus, during discharge the electrical energy stored in the electrolyte is depleted as it does useful work. We stop pumping when we sense the system is fully discharged or until there is no further demand for the stored electricity.

The entire charge/discharge process is fully reversible and either partial or full charge/discharge cycles are possible. Most important, there are no chemical or physical changes in the energy converter that can create durability problems as they do in conventional batteries. There is only a change in the chemical state of the electrolytes; and the energy converter itself is not altered in any way, with the entire system ready for the next charge/discharge cycle.

Renewable Energy

"Renewable energy is here to stay and creative & cost efficient energy storage solutions - the key to unlocking significant value at scale."

The future is here

"The future of sustainable energy storage is here and TAM ENERGY is poised to take its position in this important field of renewable energy for the next generations." TAM Energy will be launching its manufacturing facility in South Africa in early 2021 and be ready to market in the second quarter of 2021."

innovative energy storage solutions

Core innovation

ElectriStor™ Core Innovation

The unique benefits offered by our ElectriStor™ product platform are a result of quantum improvements in cost and performance over earlier liquid based energy storage systems. These improvements are based on proprietary ElectriStor™ technology components discussed on the Technology Platform page. Application benefits are also detailed on the Product page and are based on a number of proprietary innovations unique to the WattJoule ElectriStor™ platform.  WattJoule has a three-generation ElectriStor™ product pipeline in various stages of development/maturity.

The basis of our improvements is a core set of innovations based in turn on recent advances in electrochemical energy storage technology (redox flow batteries), electrochemical power generation technology (fuel cells) and advanced nanomaterials engineering. Our innovations are based, in part, on a world-class energy storage R&D effort. From this effort, we have exclusively licensed technology that we are commercializing as the ElectriStor™ platform.

ElectriStor™ Foundational R&D Effort

ElectriStor Foundational R&D Effort

The basis of our improvements is a core set of innovations based in turn on recent advances in electrochemical energy storage technology (redox flow batteries), electrochemical power generation technology (fuel cells) and advanced nanomaterials engineering. Based on this collective set of innovations, introduction of our Generation 1 product to the market provides WattJoule with a strong and defensible competitive advantage in both cost and performance over many existing electrical energy storage platforms for the stationary market. Our technical team has pioneered these innovations by combining advanced design approaches, new materials and cumulative experience in these fields.

Below is a summary of the key ElectriStor™ metrics as they compare to current vanadium redox battery system metrics in the market today. The metrics are indicated for each of our three platform generations.

ElectriStor™ has Superior Metrics Across the Board

¹ Cost based on the historical average price of V205


innovative energy storage solutions

technology platform

ElectriStor™ Technology Platform

WattJoule’s core innovations and IP portfolio are embodied in four critical, integrated, proprietary technology components that comprise the ElectriStor™ platform as shown and detailed below. Our technology is protected by a growing IP portfolio of patents, patents pending and trade secrets. We have also acquired and exclusively licensed IP as part of our portfolio.


Technology Platform

WattJoule Core Material Set

WattJoule has developed a core set of proprietary materials to enable higher performance, lower cost, long life, scalable supply and market defensibility. These materials incorporate innovations in the use of advanced nano-based and engineered composite materials. Core materials are our electrolyte active materials and additives; stack separator, electrode, bipolar plates, and flow frames; and multiple coatings and catalysts. Working with our strategic partners, we have developed readily scalable manufacturing processes that utilize in-place manufacturing infrastructure capability with little added capital investment.


WattJoule Liquid Electrolyte

The electrolyte is the energy storage medium of our system. The ElectriStor™ electrolyte family utilizes advanced chemistries that work in close conjunction with our core material set and energy conversion stack. Today’s electrolytes for vanadium redox batteries have low energy density, a restricted temperature range requiring active cooling equipment, and need costly high-purity vanadium. In contrast, WattJoule’s liquid electrolyte stores more energy per liter, requires no expensive cooling, and reduces the amount, purity and cost of vanadium over successive generations.  We have also achieved a formulation that has demonstrated long-term stability and durability over 3000 cycles and counting. There are no known mechanisms that can cause our electrolyte to deteriorate over time.

Improved energy density means less liquid is needed to store an equivalent amount of energy. This means a much-reduced system installed cost and footprint.  Improved temperature range means no need for air conditioning, chillers and associated equipment. This means a much lower system capital cost, operating cost and footprint. By eliminating this active cooling requirement overall system efficiency is improved for long term operating savings.

Vanadium is the active material in the electrolyte that stores the energy and is the primary electrolyte cost driver. In Generation 1, WattJoule has achieved both a better utilization of this material and has invented a better way to use a lower purity grade vanadium. The net effect is reduced cost. In Generations 2 and 3, we are developing a pathway to advanced chemistries that will lower electrolyte cost even further.

Electrolyte comprises a major part of the ElectriStor™ system and ours is inexpensive to make. We make our electrolyte with commonly used industrial grade chemicals within an existing volume supply chain. Working with our strategic partners, we have developed a simplified electrolyte manufacturing process that utilizes in-place manufacturing infrastructure in use by today’s chemical industry. No ultra-expensive GigaFactory is required. We can figuratively flip a switch and be producing over 100 MegaWatt Hours of energy storage equivalent liquid in a matter of months.


WattJoule Energy Converter Stack

The actual conversion of electrical energy to electrochemical energy, and vice versa, is accomplished in a redox flow cell. Arrays of these cells are built into a stack to handle larger and more usable quantities of electrical power. This stacked array of cells is referred to as an energy converter stack, or simply a stack.

WattJoule stacks are a critical component of the ElectriStor™ system. Our stacks are based on our Core Material Set (described above), especially the electrode, separator and bipolar plate components. Our stack incorporates a number of design innovations that, together with our Core Material Set, translate to higher power density, higher conversion efficiency, lower electrical impedance and lower cost. WattJoule stacks are also optimized for use with WattJoule electrolyte to insure durable, long-term operation.

A major feature of the WattJoule stack is its ability to handle considerably more power than what is normally supported by state-of-the-art stacks of the same size. This is referred to as higher “power density.” Put another way, for any given power rating, WattJoule stacks are significantly smaller, by a 6X factor in size! This means far less material use and cost savings.

WattJoule stacks are engineered to be highly durable and easily manufactured. How do you scale manufacture megawatts of stacks with high reproducibility? The answer is design-for-manufacture and robots. WattJoule has been working with its contract manufacturing partners to ensure that the volume transition from manual to fully automated robotic stack assembly will be seamless and cost effective. We project the ability to rapidly scale into megawatts of stack production with a relatively small capex investment. This means no ultra-expensive GigaFactory required!


WattJoule System Design

Our ElectriStor™ system is designed and built as a complete DC modular system with the electrolyte, tanks, stacks, pumps, heat exchanger, and proprietary system-level controls. The system is designed to be assembled with minimal labor and components.

System-level controls consist of an integrated software and sensor package that implements how the entire system is charged, discharged, and operated in a manner that insures safe, efficient, long-term reliable operation. WattJoule has developed innovative sensor technology to solve measurement problems unique to flow batteries yet fundamental to their proper long term operation.

On the system software front, WattJoule provides two levels of software. First, at the Battery Management System (BMS) level, software is embedded in the ElectriStor™ electronic control system that comes bundled with the hardware storage module, to control module specific operation. This level of software also provides clustering of ElectriStor™ modules to form large arrays of storage systems for large storage capacity requirements.

The second level is the all-important Energy Management System (EMS) level. This is the software that sits between ElectriStor™ and the utility electrical grid, and typically other systems, e.g. a solar array, a full electrical service for an entire building, and perhaps even another storage system. At the EMS level, WattJoule can provide a proven third-party OEM EMS software that has been pre-integrated/pre-tested with both our ElectriStor™ system and select AC-DC power conversion equipment. These proprietary software components make OEM integration fast, cost effective and surprisingly flexible as delivered. Of course, we can always work with OEMs to integrate their proprietary EMS software with ElectriStor™ BMS level software, if they choose that option. Or alternatively, we can assist with the integration or other third-party EMS level software packages.

innovative energy storage solutions

OEM platform

ElectriStor™ OEM Platform

Our customers, energy storage system integrators, have varying needs based on different business models, engineering expertise, manufacturing capability, etc. WattJoule’s ElectriStor™ product platform enables these OEM system integrators to rapidly build full energy storage systems for their specific customer project requirements. Our platform is a modular, scalable system that requires a minimum of non-recurring engineering time for any one project. We can provide the complete DC storage system so that our customers can provide significant value-add in terms of the balance-of-system:  enclosures and ventilation, AC-DC power conversion, electrical protection and energy management software. However, WattJoule can offer any or all of these balance-of-system components, as our customers require. This allows system integrators to take on as much, or as little, of the engineering and manufacturing effort as their internal resources allow.

ElectriStor™ is a flexible and highly scalable energy storage platform. Power and energy are completely independent in our platform and enable the deployment of large energy plants cost effectively optimized for the application at hand. From a practical design standpoint, power can range from 1kW to 500MW. Energy can range from 10kWh to 1GWh. No other storage technology offers this capability. As storage duration times expand beyond 5 hours the economic benefits of the platform become crystal clear vs. lithium-ion.

The ElectriStor™ platform consists of two major modules:  an energy conversion module and an energy storage module. The energy conversion module contains WattJoule proprietary energy converter stacks coupled with off-the-shelf pumps, sensors and controls packaged together. The energy storage module is a specialized tank assembly that contains WattJoule proprietary electrolytes. To obtain higher power levels, you cluster together energy conversion modules. To obtain higher energy levels, you can either increase the size of a pair of tanks and/or cluster pairs of tanks together. Clustering is easily accomplished in our modules via a unique control system and electrical architecture that auto-synchronizes multiple modules. Our entire platform makes heavy use of proven off-the-shelf components already in mass production from qualified vendors.

System integrators interested in utilizing ElectriStor™ in their storage solution should contact us to explore customized system configurations for their applications and projects. WattJoule offers sourcing of modules, or just core components, such as electrolyte and stacks. We also offer design-in engineering support and a unique multi-tier licensing option for those integrators who prefer to self-manufacture.

ElectriStor™ Evaluation Systems

innovative energy storage solutions

technology core benefits

ElectriStor™ Core Benefits

WattJoule’s ElectriStor™ product platform has multiple core benefits versus competitive energy storage solutions. Let’s explore each of these benefits in more detail.


Durability by Design

A long lifetime of 20 years is a requirement for energy storage systems and is similar to what solar energy systems provide today. Early vanadium flow battery systems have demonstrated well over 10,000 cycles because the fundamental chemistry is highly stable and does not degrade over time. Similarly, ElectriStor™ has been tested thousands of cycles with no degradation in its vanadium electrolyte performance. In contrast, lithium-ion batteries always exhibit a small cycle-by-cycle degradation, limiting their useful lifetime to a maximum of 3,000 cycles with restricted charge/discharge window and temperature range. This means you would need to purchase your lithium-ion battery packs three times to obtain 10,000 cycles. That’s an expensive proposition. ElectriStor™ has been designed with highly durable materials based on engineered plastics and composite materials to give long life and trouble free operation. Key components, such as the electrolyte pumps, can be easily replaced in the field in order to extend system life.


Low Capital & Life Cycle Cost

Two important cost metrics used today are the installed capital cost in $/kWh of rated storage capacity and the Levelized Cost of Storage (LCOS) in $/MWh of actual storage supplied over time for a given application scenario. The LCOS metric is becoming a better industry metric for comparison because, unlike installed capital cost, LCOS takes into account all costs over the actual system lifetime, including all operational costs, repair costs, and costs related to system efficiency. These additional factors are significant. ElectriStor™ is very competitive on an LCOS basis because we start with a low installed capital cost and combine that with a 20-year system lifetime and minimal operational and maintenance costs.


100% Charge/Discharge Window

The ElectriStor™ system allows the use of up to a 100% charge/discharge window on every cycle, enabling maximum application flexibility. In contrast, lithium-ion use in stationary storage systems strictly limits this window, according to a complex map of power, temperature and cycle count in order to guarantee lifetime. This means that running multiple storage applications simultaneously may become difficult to implement and possibly unfeasible in some situations.


Reduced Footprint

Early flow battery systems had quite a large footprint. By significantly improving system energy density and power density, and by eliminating the need for specialized cooling equipment, we significantly reduce the size and weight of our entire system. ElectriStor™ requires less real estate for siting and lowers overall installation costs.


System Flexibility & Scalability

WattJoule’s ElectriStor™ product platform enables OEM system integrators to rapidly build and scale large energy storage systems for their end user customer project requirements. Our platform is a modular, scalable system that requires a minimum of non-recurring engineering time for any one project. Since power and energy are fully independent in our system, there is a large range of flexibility based on the application. To obtain higher power levels, you cluster together energy conversion modules. To obtain higher energy levels, you can either increase the size of an individual tank and/or cluster more tanks together. Power can range from 20kW to 200 MW. Energy can range from 100kWh to 1000MWh. The two are completely independent in our platform.


No Refrigerated Cooling Required

Many of today’s energy storage systems require refrigerated cooling; otherwise their systems will degrade and fail prematurely. In contrast, ElectriStor™ requires simple air cooling. This means no costly air conditioning equipment and a higher net system efficiency, since we don’t incur an energy loss to run the AC, and there is less equipment to maintain.


No Fire or Explosion Hazard

We have all heard about smartphones, laptops, hoverboards, aircraft, electric cars and large storage systems catching on fire due to battery failure. WattJoule electrolyte is over 60% water and contains no flammable materials. Based on this and its inherent design, ElectriStor™ cannot catch fire or explode like conventional lithium-ion and sodium sulfur technology. This is a major benefit when large energy storage systems, containing massive amounts of energy, are sited close to populated buildings. This removes a major concern by system integrators, developers, fire authorities and insurance companies. In fact, no fire suppression equipment is required for our systems.


Longer Duration Storage Improves Costs

Let’s say you have two identical energy storage systems with the same power rating. One is a lithium-ion system and the other is an ElectriStor™ system. The cost of the lithium system in terms of $/kWh for the battery packs, for any energy rating in hours, will be essentially constant. In contrast, ElectriStor™ will have a continually declining $/kWh cost because of the independence of the power (energy conversion) and energy components of the system. When storage times become 5 hours or greater, ElectriStor™ is increasingly competitive to lithium-ion solutions. This is because as we need to increase storage time we only need to add liquid to the system and increase the size of our tanks. All of the other energy conversion hardware remains exactly the same.


A Sustainable Solution

ElectriStor™ was built with sustainability in mind. In the first place, our major global mission is to enable the broad use of sustainable renewable energy through the use of energy storage. Secondly, our equipment and materials are designed for durability and simple repair of components. This allows one to continually extend ElectriStor™ useful lifetime to 20 years and beyond. The liquid electrolyte does not degrade, and the vanadium and other chemicals can be easily removed, recycled by simple processes, and reused in the future. All the hardware components we use are made from materials that can be fully recycled.