Context: CREATE TABLE table_23958917_1 (stacks VARCHAR, unit_capacity__2009_ VARCHAR)
Question: Name the number of stacks for 1 & 2 235 mw 3 & 4 88.2 mw
Answer: SELECT COUNT(stacks) FROM table_23958917_1 WHERE unit_capacity__2009_ = "1 & 2 235 MW 3 & 4 88.2 MW"