To achieve energy sustainable and green solutions, countries around the globe are implementing large scale energy harvesting + storage projects leading eventually to carbon-free economy. This quite complex and ambitious plan depends among other things on large Li battery systems that are capable of storing energy in GW range. On the PV technology side, there are options to choose from, and the green technology status is achievable despite the drawback set by poly-Si raw material manufacturing (see our previous article on poly-Si plants explosions here). On a storage technology side, large battery systems are currently led by Li battery technology that still suffers from growth of lithium dendrites towards another electrode to form a short circuit and poor protection of individual cells in a module causing heat from a compromised cell to quickly spread across the entire container. Safety issues of Li battery storage can compromise the development of successful carbon-free energy generation/storage systems. What are the competitive alternatives to Li-ion storage? Have industry safety standards been improved for Li battery storage? Can MW-GW renewable energy harvest/storage parks be called “green” and “beneficial for people and environment”?
By Olga Griffith
In April of 2019 Arizona battery facility had a fire incident originally reported here. This incident became fully resolved more than a year later as published by Greentech Media, explaining the cause of fire to be a formation of Li dendrites that shorted one cell in a module leading to fire (this phenomenon is known as thermal runaway) that quickly spread to neighboring cells causing the build-up of toxic gas (hydrogen fluoride or HF), which was further released upon opening the battery enclosure by the first responders. The lack of safety features such as toxic gas sensors and proper ventilation, along with failed fire suppressant amplified this incident and caused health damages to the responders. More reported examples of Li-ion storage related fires include 64 house fires in 2015 in Australia caused by Li battery pack failures, 23 fires from 2017 to 2019 in energy storage systems in Korea have been reported. The Li-ion storage system that supports wind power generation in Belgium has exploded into fire in 2017 releasing highly toxic HF gas into the air. Here are the hazards of exposure to HF fumes: breathing in HF at high levels can cause death from an irregular heartbeat or from fluid build-up in the lungs; at lower levels breathing HF can damage lung tissue and cause swelling and fluid accumulation in the lungs (pulmonary oedema); eye exposure to hydrogen fluoride may cause prolonged or permanent visual defects, blindness, or total destruction of the eye (more details can be found here).
Despite the vast evidence of Li-ion storage systems failures, there are many storage projects on a rise. The largest so far 1500 MW Li-ion battery storage is under construction in USA by Vistra, followed by 150 MW storage by Hornsdale Power in Australia, 50 MW storage by Stocking Pelham in UK, 48 MW project by Jardelund in Germany and more, as published by PV magazine. Planning and implementing these large Li-ion storage projects is not a problem, but not having any assurance in robust safety of these huge battery systems is a problem with high potential health risks for many people.
In addition to improving safety of existing commercial Li-ion grid storage technology, alternative technologies need to be developed as well. One of them is a Zinc-air battery technology that does not suffer from dendrite-related shorts and formation of HF fumes. A promising comparison of emerging Zinc battery tech with current market leader Li battery tech is recently reviewed by Greentech Media.
To conclude, there are great technological options available to implement green renewable energy solutions that all of us will benefit from. However, in this chase after green tech it is important not to let corporate profits dictate the path to green energy future!