How does the shift from causticization to membrane electrolysis affect China's NaOH cost structure?

How does the shift from causticization to membrane electrolysis affect China's NaOH cost structure?
China's caustic soda industry has almost fully transitioned to ion-exchange membrane technology, which yields higher-concentration liquid caustic at lower energy use than the older diaphragm process. The historical causticization route, reacting soda ash with lime, is now largely obsolete because it is costlier and less efficient. The key cost driver today is electricity, not salt. This makes caustic soda pricing highly sensitive to power tariffs, unlike resource-based chemicals that benefit from upstream ore cost support. Since 2020-2025, national output grew from 36.7 million to 46.5 million tons, but demand growth, led by alumina, paper, textiles, and water treatment, has not kept pace with the systematic supply increase tied to chlorine co-production. New energy applications like lithium hydroxide add only marginal demand.