user: Question: How many power stations are connected to grid at Heysham 2
Columns: ['AGR Power Station', 'Net MWe', 'Construction started', 'Connected to grid', 'Commercial operation', 'Accounting closure date']
Types: ['text', 'real', 'real', 'real', 'real', 'real']
Sample row: ['Dungeness B', 1110.0, 1965.0, 1983.0, 1985.0, 2018.0]
SQL:

assistant: SELECT COUNT("Connected to grid") FROM "Table" WHERE "AGR Power Station" = 'Heysham 2';