Energy Storage 2020: It’s Not Just About Lithium-Ion Batteries Any More
Many of us have tunnel vision on the subject of energy storage. We think lithium-ion batteries are the beginning, middle, and end of the discussion. Largely that’s because of Elon Musk and Tesla, who have built their incredible history of success both in transportation and energy storage on lithium-ion batteries. Yet there are other types of storage solutions, many of which will begin to share the spotlight with lithium-ion batteries in 2020.
The US Department of Energy’s Advanced Research Projects Agency — ARPA-E — is funding research by 10 organizations with one common goal — creating long term energy storage systems that cost $0.05 per kilowatt hour or less. Five of the projects are scheduled for completion in 2020 and the rest in 2o21. After they are complete. ARPA-E plans to fund small scale field trials to determine which are commercially viable. According to PV Magazine, the research falls into several general categories.
Sulfur Flow Batteries
A startup based in Somerville, Massachusetts, Form Energy is staffed by people with previous experience at Tesla, Aquion, and A123. It is working on sulfur flow batteries it says will permit “full-week backup capability at a factor of 10 times or greater cheaper” according to co-founder Marco Ferrara. Sulfur flow batteries have the lowest chemical cost of all rechargeable batteries but suffer from low efficiency. Form Energy is working on new anode and cathode formulations, membranes, and physical system designs to increase efficiency
United Technologies is partnering with Lawrence Berkeley National Laboratory, MIT, and Pennsylvania State University to research sulfur and manganese flow batteries. The objective is to “overcome challenges of system control and unwanted crossover of active materials through the membrane.”
Electricity to hydrogen
As renewables become more common, there will be instances when the supply of electricity exceeds demand. What to do with the excess? One solution is to use it to break water into into its component parts — hydrogen and oxygen. The hydrogen produced can be used later to make electricity in fuel cells but converting energy back and forth from one form to another is not always very efficient.
A team at the University of Tennessee, Knoxville is working to improve that efficiency by creating an advanced regenerative fuel cell — a single device that functions as both a fuel cell and an electrolyzer. The device the team is working on will convert hydrogen and oxygen to hydrogen peroxide instead of water. “The benefit of using peroxide instead of water is higher efficiency in both charging and discharging the system,” ARPA-E says.
Zinc-bromine flow batteries
Primus Power already makes zinc bromide flow batteries. With help from ARPA-E, it aims to “eliminate the need for a separator to keep the reactants apart when charged,” by “taking advantage of the way zinc and bromine behave in the cell.” The new configuration is expected to allow all the electrolyte to be stored in a single tank instead of multiple cells, thus reducing the amount of hardware needed to complete a system, which will lower costs.