Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Unit | Reactortype | Net capacity | Gross capacity | Construction started | Electricity Grid | Commercial Operation | Shutdown |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Novovoronezh-1 | VVER-210 (prototype) | 197 MW | 210 MW | 01.07.1957 | 30.09.1964 | 31.12.1964 | 16.02.1988 |
| Novovoronezh-2 | VVER-365 (prototype) | 336 MW | 365 MW | 01.06.1964 | 27.12.1969 | 14.04.1970 | 29.08.1990 |
| Novovoronezh-3 | VVER-440/179 | 385 MW | 417 MW | 01.07.1967 | 27.12.1971 | 29.06.1972 | 2016 planned |
| Novovoronezh-4 | VVER-440/179 | 385 MW | 417 MW | 01.07.1967 | 28.12.1972 | 24.03.1973 | 2017 planned |
| Novovoronezh-5 | VVER-1000/187 (Prototype) | 950 MW | 1000 MW | 01.03.1974 | 31.05.1980 | 20.02.1981 | 2035 planned |
Question:
When did the Electricity Grid 28.12.1972 officially shutdown?
Answer:
2017 planned