Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_236 ( "Power Source" text, "Number of Generators" real, "Power Capacity (GW)" text, "% of total Capacity" text, "Capacity factor" text, "Annual Energy (billion kWh)" text, "% of annual production" text )

### Question ###
What is the power capacity when the generators were 781?

### Accurate SQL ###

SELECT "Power Capacity (GW)" FROM table_236 WHERE "Number of Generators" = '781'