1. Fastest charging may overload any direct connection to the ac grid in that location
2. Even for slower charging the local grid connection may not cope
3. People may want to be sure they are using renewable energy and such a module can be visibly connected to renewable power sources such as solar and wind power
4. Charging may be provided in disaster zones and at events
5. It can be an uninterruptible power supply
For example, Green Charge Networks in the USA (Prosser and ConEdison) finds that a remarkable 7-12% of installations there need local grid upgrade so they have developed a transportable, dedicated substation for this purpose which contains a 26 kWh lithium-ion battery roughly equivalent to that in a Nissan Leaf, and appropriate contacted outlets, including for Level 3 fastest charging. The total grid upgrade unit costs only $2500/kWh and, being transportable, it will also be useful at events, it says.
By contrast, Gildemeister Energy Solutions in Germany offers CellCube in Europe which is a larger, more powerful equivalent together with compatible green power sources - wind and solar - as shown below.
Source Gildemeister Energy Solutions
It says, The vanadium redox flow large battery ensures an uninterrupted power supply. It is independent of weather-related fluctuations, temperatures, length of day or unstable grids. the vanadium redox flow large battery ensures an uninterrupted power supply. It is independent of weather-related fluctuations, temperatures, length of day or unstable grids. It is characterised by a high level of safety, storage stability and very fast reaction times, and it can be integrated into existing energy systems in a wide range of applications around the world. Sophisticated technology, proven components, plus intelligent sensor systems and control functions make CellCube absolutely low-maintenance. With the flow battery controller, a clever monitoring device ensures comprehensive control and guarantees safe energy supply around the clock.
The basic module is shown below.
Gildemeister Energy Solutions
Four used together provide 40kW and 40kWh says the company. It argues that, The vanadium-based redox flow CellCube FB 200-400 is the perfect solution for industrial use. With 200 kW and 400 kWh, the CellCube FB 200-400 provides large energy reserves, for example, to stabilise supply voltages, to buffer energy output, or wherever an uninterrupted power supply is of essential importance.
The company points to the following fields of application.
Grid support: for the stabilisation of low- and medium-high voltage systems, as an energy reserve, for peak usage relief (compensation of load and production peaks)
Backup: use as inline UPS system with frequency and amplitude decoupling, state-ofthe-art system safety
Wind and solar parks: a buffer to stabilise energy output and fluctuations; higher performance security through energy reserves in times of reduced performance
Repowering: investment protection: CellCube ensures constant energy feed even after the write-off of a wind/solar park.
Gildemeister explains: The liquid energy carriers are stored in two tanks and are pumped through electro-chemical cells.Depending on the applied voltage, the energy sourcesare either electro-chemically charged or discharged. In this context, the electrical charge regulators and inverters function as the interface to the electrical source, or, respectively, to the appliance.
The claimed benefits are:
Almost unlimited lifespan of the energy sources (the system is designed for a life of up to 20 years)
Electrolytes can be reused even after 20 years
Output and energy are scalable independently of each other
Deep discharge does not result in damage
Unlimited cyclisation (loading/unloading) at the energy source without effect on lifespan
Gildemeister Energy Solutions
Another participant in this market is Eon in Germany. E.ON Energy Research Center aims at improving the Vanadium Redox-Flow Battery. Improving membrane behavior is in the focus of this work. Furthermore, studies for optimizing the whole system will be conducted. From the point of view of this power utility, redox-flow batteries are an option for large-scale electrical energy storage for peak shaving and load leveling ranging from a few kWh to hundreds of MWh. One of the most important features of these batteries is that the energy and power capacity of the system can be separated. Thus, the power of the system is determined by the number of cells in the stack and the size of the electrodes, whereas the energy storage capacity is determined by the concentration and volume of the redox-fluid.