Advanced battery energy storage solutions can improve the efficiency of renewable energy and the need is growing exponentially. In 2021 probably 20 percent electricity production came from renewable energy sources. According to the International Energy Agency, this number must increase to two-thirds by 2030 to achieve zero goals. To truly unlock the potential of renewables, we need larger energy storage systems, and a wide range of battery chemistries will be needed to meet this demand.
Three widely used battery technologies are redox flow lead, lithium, and vanadium. There are a number of factors to consider when choosing the most appropriate battery chemistry to meet your energy storage needs.
Like other technologies, batteries have evolved in design and manufacturing. With ambitious clean energy transition goals, the public and private sectors need to work together to accelerate innovation from R&D to prototype and early adoption.
Invented in 1859, lead is the most commercially advanced of the three battery technologies and has been the primary energy storage solution for many years. Regardless of its lifespan, there are still areas where further research could reveal even greater potential capacity. Lead is also relatively cheap compared to other battery chemicals.
Lithium is another commercially advanced technology on a scale that is currently necessary. It was originally used for consumer goods in the early 1990s. Due to its high energy density, lithium is currently the dominant battery technology for energy storage. Lithium comes in a wide variety of chemical combinations that can be somewhat daunting to choose from, with nickel-manganese-cobalt (NMC) and lithium-iron phosphate (LFP) having the highest levels of maturity.
While vanadium redox battery technology has been around for over 50 years, it is the least commercially developed of the three chemistries. The concept of vanadium flow batteries was developed by NASA to power satellites. This chemistry has the potential to become a leading solution for long-term energy storage.
Renewable energy must be sourced and distributed efficiently to be sustainable. Energy storage solutions used to achieve this goal should also have a low environmental impact.
Lead is the most sustainable of the three battery chemistry types. Lead-acid batteries have a 99 percent recycling rateand the lead acid battery industry is well developed circular economy which reuses and recycles the lead, electrolyte and plastic components of used batteries.
Vanadium is almost infinitely reusable. The electrolyte that makes up most of the vanadium battery system can be dried, cleaned as needed, and then used in another system. According to the US Geological Survey, about 40 percent vanadium is recycled.
Currently, lithium is the least sustainable of the three chemicals. The recycling rate is less than five percent, due to the cost and complexity of the process. The lithium battery must be disassembled and crushed, then melted or dissolved in acid. While recycling processes are not yet widely available, this rapidly developing field will improve the capture of materials from lithium batteries. These new solutions are already producing modest amounts of battery material at a fraction of the cost of the original materials.
Common applications for energy storage include energy shifting, such as storing renewable energy for use at another time or storing energy from the grid to be used during an outage. Each of these applications has a different operating time and this time is a factor in choosing the most suitable battery chemistry.
Vanadium is best suited for long-term energy storage (6 hours or more operating time). It has a larger footprint but is easier to expand. More electrolyte is added to the battery system to increase endurance. Footprint and weight are considerations for vanadium systems, but these systems can be packed closer together due to the high level of safety these systems offer.
Lithium is suitable for short- to medium-term operation (from a few minutes to four hours of operation). To extend life, additional cells are added to the battery system, increasing the footprint and planning needed to meet emergency access requirements in the event of a security event. There is a tipping point as cells are needed for extended life where the footprint of a lithium system with adequate safe spacing can exceed that of a vanadium system.
Lead also works best in the short to medium term, especially in situations where the depth of discharge is relatively shallow and the main gating factor is low entry cost. Duration can be extended by adding cells, similar to a lithium system. However, weight and space are significant factors in increasing operating time.
A useful life
Useful life is a combination of cycle life, calendar life and operating environment. The life of a lithium battery is about 10 to 15 years, while a vanadium battery can last more than 30 years. Lead acid batteries can last up to 30 years depending on design and applications.
Lead-acid batteries are typically measured by cycle life, which is strongly affected by depth of discharge, capable of 1,200 to 1,800 cycles at 80% depth of discharge depending on design. Lithium battery life is generally specified at much greater depths of discharge in the range of 80 to 100 percent and offers two to three times the life of lead-acid batteries at around 3,000 to 10,000 cycles. In contrast, vanadium battery technology has an almost infinite lifetime. With all battery technologies, this lifespan is dependent on proper maintenance.
Lead and lithium are sensitive to higher temperatures. The ideal operating temperature for these battery systems is between 20°C and 35°C, with some impact on lifetime above this range. Vanadium systems can withstand higher heat, up to 50°C.
All three battery systems are generally safe, provided they show no defects or damage. Lithium batteries are sensitive to high temperatures and naturally flammable. If the temperature exceeds a critical level or if the damage leads to an internal short circuit, thermal leakage occurs. A battery management system ensures that the lithium cells remain within the specified operating range. As an additional precaution, lithium batteries should be separated as much as possible to prevent fire from spreading throughout the system.
The safety of lead-acid battery systems is often determined by their design. Flooded systems contain a liquid electrolyte that requires a burst protection system and ventilation for potential gassing. VRLA batteries require a well-designed charging system to monitor and control voltage and temperature. Lead is also prone to thermal events, but these incidents are much more manageable compared to lithium battery systems.
Vanadium is generally considered safer compared to other battery technologies. Although the electrolyte itself is not flammable or prone to thermal runaway or deflagration, it is corrosive and requires appropriate containment strategies.
Energy is vital to keep our economy moving. Thanks to the diversification of energy sources, our country is better insulated from supply shocks affected by foreign imports. Dependence on imports also leads to security flaws. Recent supply chain shortages and disruptions have shown that the domestic supply chain should be another important consideration for energy storage systems.
Lead is readily available and produced domestically. Domestic recycling ensures 73 percent domestic demand for lead. Over 90 percent domestic demand for lead-acid batteries is met by North American producers. The US lead-acid battery industry is supportive more than 92,000 jobs and a total economic impact of over $26 billion.
Lithium is one of the 50 mineral commodities listed as critical for the American economy and national security. Australia is a world leader lithium mine production, followed by China and Chile. While the US has about 4 percent of lithium reserves, we produce less than 2 percent of the world’s reserves.
Vanadium is also on the list of critical minerals. China leads the world vanadium production, then South Africa and Russia. There is currently no domestic production of vanadium, leaving the US dependent on foreign sources.
The energy sector is a resource 76 percent greenhouse gas emissions worldwide. Replacing fossil fuel energy with renewable energy would dramatically reduce carbon emissions. The United States has set a goal achieving net zero emissions by 2050 and creating a carbon-free energy sector by 2035.
To achieve this goal, emphasis will be placed on renewable energy sources such as wind and solar. This clean energy transition will require multiple, reliable, sustainable and safe energy storage solutions. These solutions will depend on different advanced battery technologies, and each chemistry will have its place to match supply and demand.
This article is sponsored by Stryten Energy.
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