Bromine-based flow batteries are highly efficient at storing and releasing energy while reducing costs and impact on the environment.
The world’s population is expected to grow by two billion by 2050, and global energy demand is expected to roughly double during the same period. At the same time, the power generation sector is undergoing a major transformation as economies and consumers move away from fossil-energy-based centralised power stations towards low-carbon, renewable-energy-based systems.
As the supply of renewable energy grows, energy storage becomes more important. Current growth projections for renewable energy storage show that wind and solar energy will account for 20 to 39 per cent of power generation by 2060, compared to the current 4 per cent. However, the production of electricity from wind and solar can vary significantly throughout the day. As a result, electricity is not always consumed at the time it is produced.
By storing, we can use clean electricity when we need it. Energy storage will play a key role in enabling economies globally to accelerate the energy transition.
Renewable energy sources and storage solutions
Energy storage allows electrical systems to use renewable energy without the need for a continuous connection to the grid. Locally, it can improve the management of distribution networks, reducing costs and improving efficiency. It can also give customers freedom to manage their own power needs.
Since the mid-2000s the EU has been proactively diversifying its energy mix with a strong focus on renewable energy. In 2015 the total share of renewable energy in final energy consumption in the EU was 15.3 per cent, up from 8.7per cent in 2005.
The increase in renewable power raises new challenges to European grid systems. The current grid capacity is strained or even insufficient to cope with the growing volumes of renewable power, as well as the increasing demand from industry and consumers for more renewable power.
Globally, pumped hydro storage (PHS) accounts for more than 99 per cent of bulk storage capacity worldwide. For a variety of factors (water availability, geography, engineering constraints and costs), further growth of PHS will not be sufficient to meet the projected energy storage requirements now being forecast – especially in the US, China, Japan and the EU.
Today there are several energy storage solutions available, ranging from pumped hydro-power to battery technologies.
Bromine-based energy storage technologies
Bromine-based storage technologies are a highly efficient and cost-effective electrochemical energy storage solution, providing a range of options to successfully manage energy from renewable sources, minimising energy loss, reducing overall energy use and cost and safeguarding security of supply.
As the chemical reaction in flow batteries is reversible, just like conventional electrochemical batteries they can be recharged without replacing the electroactive material. Typical bromine-based flow batteries include zinc-bromine (Zn-Br) and hydrogen bromide (HBr).
Other variants in flow battery technology using bromine are also under development. Bromine-based storage technologies are typically used in stationary storage applications for grid, facility or backup/standby storage.
Current deployment of bromine flow batteries can be found in Australia, the US and in the EU (France and the Netherlands). Some examples of deployed batteries include an industrial site in the Rancho Cucamonga plant in southern California and, more recently, the US Department of Defense is using zinc-bromine batteries for its military micro-grid at the Marine Corps Air Station in Miramar, California. In Australia, a flow battery producer is producing zinc-bromine batteries for deployment across the Pacific islands.
In Europe, the Photon Farmer – a Dutch dairy farm – has deployed six zinc-bromine flow batteries (totaling 60 kWh) to store self-produced solar energy that can support its milk production with sun-harvested energy. The 57.5-hectare, family-owned, sustainable and highly automated farm houses 100 cows, and has a large shed roof with a 50kW rooftop solar system.
The project was recently included in the Storage4EU initiative developed by the European Association of Storage of Energy (EASE). The initiative gathers the best energy storage projects in Europe.
How do bromine flow batteries work?
Typical bromine-based energy storage technologies are based on redox (reduction-oxidation) principles. In effect, they are a rechargeable battery consisting of one or two tanks that contain chemicals dissolved in liquids and which are usually separated by a membrane. When the two solutions flow inside the stack of the battery, they generate a charge by moving electrons back and forth between positive and negative electrodes, thus creating energy. A flow battery is technically similar to a fuel cell with recharge capabilities (electrochemical reversibility).
BSEF is the international bromine producers’ organisation. Since 1997, the organisation has been working to foster knowledge on the uses and benefits of bromine-based solutions. BSEF strongly believes in science and innovation.
Through investments in research and development BSEF members create robust bromine-based technologies meeting the needs of society. The members of BSEF are Albemarle Corporation, ICL Industrial Products, Lanxess and Tosoh Corporation.
For further information please visit www.bsef.org to learn more, and follow BSEF on Twitter @BromineInfo for the latest news and information.
 Source: World Energy Council, 2013 – World Energy Scenarios: composing energy futures to 2050
 Source: International Energy Agency, 2017 – Tracking Progress: energy storage
 Source: Eurostat