VisBlue - Renewable Energy Storage

Renewable energy storage

Save your sustainable solar energy, and power your home at night

The VisBlue battery is an energy
storage solution built around a unique Vanadium based Redox Flow battery

The VisBlue battery can store a day of solar energy, and power your home at night



The VisBlue battery doesn’t use
conventional batteries, like other energy storage solutions, but a self-developed battery, based on the
redox flow technology.


With the VisBlue battery the electrical power
and storage capacity can be scaled independently. This means that you can get a battery that is tailored exactly to your needs.


The VisBlue battery has separate major
operating components (tanks, electrolyte, pumps, electrode stack etc.), that are either recyclable or reusable in different ways.

Why use
VisBlue's Battery

for renewable

   Absolute scalability

   Lifespan of 20+ years

   Make grid purchase savings

   Internet-enabled monitoring and control

   Maximise your use of renewable energy sources

   Reduce carbon emissions

•  Inherent safety - non-flammable and non-explosive

How does it work?

• A Vanadium Redox Flow (VRF) battery has two separate tanks, one containing a positive electrolyte and one a negative electrolyte. Both electrolytes consist of the element vanadium dissolved in sulphuric acid, with the vanadium occurring in different oxidation states (valences).


• The battery has a number of battery cells as well. Each of these cells is divided into two chambers separated by a membrane, through which the ions can pass. In each chamber there is a positive or negative electrode. The two electrolytes are pumped through the cells on their side of the membranes.


• The current from the solar panels is fed down into the cells’ electrodes, where it moves electrons from the positive to the negative electrolyte, charging the battery as the liquid flows back into the tank. During discharge, this process is reversed.

Calculated usage + Calculated energy savings = Optimum battery size

VisBlue has refined the technology and made it scalable so it can be used in a variety of different contexts, e.g. in industry, in large blocks of flats and in private homes




From 25  to 500 kWh


Nominal power

From 5 to 100 kW in steps of 5 kW



80% at nominal power


Installation requirements

Installed with a hybrid inverter



20+ years


  • What are the technical specifications of a VisBlue battery?

    The VisBlue battery is based on an all-vanadium redox flow battery (VRFB), which is the most mature Redox Flow Battery technology.


    Electricity is stored electrochemically by changing the oxidation states of vanadium redox species that are dissolved in sulphuric acid and stored in two separate tanks. While charging or discharging, the two solutions are circulated through a flow cell, where the electrochemical energy is converted into electricity or vice versa.


    The basic chemical principles used in Redox Flow Batteries are similar to that of Li-ion batteries or lead-acid batteries, where electricity is stored in solid redox electrolytes. In Redox Flow Batteries, liquid redox species are used. Moreover, Redox Flow Batteries can be described as reversible fuel cells with fuels/electrolytes other than O2 and H2. Redox Flow Batteries have high (70-90 %) cyclic charge/discharge energy efficiencies, depending on the charge/discharge current. One of the attractive features of Redox Flow Batteries is scalability between storage capacity and power because the storage tank and power generation are two separate units.


    Compared to Redox Flow Batteries, based on redox species other than vanadium, the vanadium redox flow batteries have the advantage that cross contamination of ions inside the flow cell is less detrimental than in mixed species batteries and will only result in slow self-discharge. This means that, VRFBs, in principle, has an infinite lifetime. However, mechanical deterioration of the flow cell gives finite lifetime. Depending on the quality of the flow cell, the lifetime is expected to be at least 10-15 years (>3500-5500 cycles). At the same time, the vanadium species that constitutes about 30-50 % of the battery cost has significant scrap value and can be reused in a new installation. Such lifetimes are significantly higher than that of a standard Li-ion and lead-acid batteries (< 3000 cycles and <1000 cycles respectively), which together with the low cost of the vanadium redox species is the main reason for the lower cost of storage in vanadium redox flow batteries.


  • What is the cost of a VisBlue battery solution?


    Each requirement for energy storage is different and the solution is therefore tailored to
    the particular client. We are happy to discuss individual requirements to see if we have a solution
    that is appropriate for you.


  • Can the VisBlue battery system be scaled up for larger requirements?

    Yes. We can design and deploy systems using as many VisBlue units as you need for your home or office.

    All our solutions start with a specific calculation of the customer’s needs and expectations. The fact that we can scale our solutions, so the customer gets the optimum solution from the word go, is one of VisBlue’s great strengths. Our calculations are carried out using advanced simulation software, which we

    have developed for the purpose.

  • Is it environmentally sound to use Vanadium?

    Vanadium is a metal that can be found in more than 100 different minerals. Vanadium, as used
    in the VisBlue battery as vanadium electrolyte, is anticipated to have a long life span of up to 20 years in
    each battery system. If a battery system is de-commissioned for any reason, the vanadium solution
    and all the contained metal can be 100% reclaimed and re-used elsewhere.

  • Can the Vanadium in the VisBlue batteries be recycled?

    Yes. The batteries have a lifetime of 20+ years. The electrolyte can be removed after this time, cleaned by filtration if necessary and re-used.



  • What is the lifetime of a VisBlue battery?

    The batteries have a lifetime of 20+ years.


    Vanadium-based flow energy storage systems can operate forever. The active ingredient - Vanadium - is a rechargeable electrolyte, which never wears out due to the type of chemical reaction involved. The electronics and software to manage the system can be easily upgraded like any computer. The last major component — the plastic tanks that hold the electrolyte — lasts for decades.


  • Is the VisBlue battery recyclable?

    Yes. More than 95% of all the components in a VisBlue battery can be recycled. VisBlue's core battery module has major components that are either recyclable or reusable.


    As our battery has separate major operating components (tanks, electrolyte, pumps, electrode stack), these components are easy to remove and recycle in separate ways.


    The tanks and the electrolyte stack (the heart of the battery system) are made of conventional plastic.


    The stack is held within two large metal plates that are easy to recycle.


  • Benefits of the VisBlue flow battery

    Large savings

    Our solution provides savings from day one. The customer utilises a much higher proportion of the free solar energy and thus has to buy less electricity.


    Scalable to suit individual requirements

    Whatever the requirement, we can adapt the solution to the precise capacity needed by the customer. It should pay off to be environmentally conscious.


    Long lifetime

    The battery can be charged far more times than either lead or lithium-ion batteries – around 10,000 times – and without affecting capacity either.


    An eco-friendly solution

    VisBlue makes the world greener. We boost the utilization rate of solar power and make our batteries from recyclable materials. With security against tariff changes, VisBlue’s customers buy less electricity and so are less vulnerable to political measures and changes in the export tariff for surplus electricity.


    An asset when selling

    VisBlue looks good in energy accounts and will help make your home more attractive when the time comes to sell it.


  • Where is VisBlue located?

    VisBlue is situated in the University City of Aarhus in Denmark. Here we have our main offices production facilities and R&D-facilities. Moreover, VisBlue has office in Porto with ties to and collaborates with the University in Porto

     Click here to find us

The purpose of this Frequently Asked Questions (FAQ) area is to help you to learn more about the
VisBlue battery solution. Please explore the various categories here and if you can't find the answer to your question and you'd like us to look into it, please contact us.


P: (+45)  71 996 996

Bautavej 1A

8210 Aarhus V



CVR: 36427957

©2018 VisBlue





Subscribe to the VisBlue mailing list for all the latest company news and product updates.