I think they first plant will have more than 30 GWh annual capacity
"GM looking to build second battery plant in U.S. - WSJ
March 4 (Reuters) - General Motors Co is looking to build a second battery factory in the United States with South Korean joint-venture partner LG Chem Ltd, the Wall Street Journal reported on Thursday, citing people familiar with the matter.The companies are close to completing a decision to locate the plant in Tennessee, the report here said.Both GM and LG did not immediately respond to Reuters requests for comment.The companies are already building a $2.3 billion battery plant in northeast Ohio that is expected to open in 2022 and eventually supply enough batteries to power electric vehicles."