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

### Instruction:
When did the Electricity Grid 28.12.1972 officially shutdown?

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

### Response:
SELECT Shutdown FROM table WHERE Electricity Grid = 28.12.1972