CREATE TABLE table_239 ("Power Source" TEXT, "Number of Generators" FLOAT, "Power Capacity  ( GW ) " TEXT, "% of total Capacity" TEXT, "Capacity factor" TEXT, "Annual Energy  ( billion kWh ) " TEXT, "% of annual production" TEXT)

What is the number of generators where the power capicity is 78.7?
SELECT COUNT("Number of Generators") FROM table_239 WHERE "Power Capacity (GW)" = '78.7'
SELECT COUNT("Number of Generators") FROM "table_239" WHERE "Power Capacity (GW)" = '78.7'