Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Which Commercial Operation has both a Gross Capacity of 417 mw and an Electricity Grid 27.12.1971?

### Inputs:
table_name: table, columns: ['Unit', 'Reactortype', 'Net capacity', 'Gross capacity', 'Construction started', 'Electricity Grid', 'Commercial Operation', 'Shutdown']

### Response:
SELECT Commercial Operation FROM table WHERE Gross capacity = 417 mw AND Electricity Grid = 27.12.1971