user: Question: What is the power capacity when the generators were 781?
Columns: ['Power Source', 'Number of Generators', 'Power Capacity (GW)', '% of total Capacity', 'Capacity factor', 'Annual Energy (billion kWh)', '% of annual production']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Hydro', 4048.0, '78.7', '7.5', '0.463', '319.4', '7.7']
SQL:

assistant: SELECT "Power Capacity (GW)" FROM "Table" WHERE "Number of Generators" = 781.0;