IIT JEE M.TECH ENGINEERING COURSES : An important very BASIC doubt !

This question is regarding M.Tech admissions in IIT'S...if anyone knows my questions answer [the specific question] , THEN PLS DO REPLY !

Is it possible for every Engineering graduate to take / opt for any of the following exams given below :

MY QUESTION SPECIFICALLY : IS IT POSSIBLE FOR A CIVIL ENGINEERING GRADUATE TO OPT FOR ENERGY ENGINEERING (CODE : 19) / RENEWABLE ENERGY (CODE : 46) ??

SOURCE : http://gate.iitkgp.ac.in/gate10/discipline.php

DISCIPLINE CODES

Discipline

Code

Engineering/Technology:

Aerospace Engineering

01

Aeronautical Engineering

02

Agricultural Engineering

03

Applied Mechanics

04

Architecture

05

Automobile Engineering

06

Biochemical Engineering

07

Biomedical Engineering

08

Biotechnology

09

Ceramic and Glass Technology

10

Chemical Engineering

11

Chemical Technology

12

Civil/Civil and Environmental/Structural Engineering

13

Computer Science and Engineering/Technology

14

Control and Instrumentation

15

Electrical Engineering

16

Electro-Chemical Engineering

17

Electronics and Comm./Electronics Engineering/Comm. Engineering/Telecommunication Engineering

18

Energy Engineering

19

Environmental Engineering

20

Food Technology/Food Processing Engineering

21

Industrial Engineering

22

Industrial Management

23

Information Technology

24

Instrumentation/ Electronics/Control

25

Instrumentation and Process Control

26

Manufacturing Engineering

27

Material Scinece and Engineering

28

Mechanical Engineering

29

Mechatronics

30

Medical Instrumentation

31

Metallurgical Engineering/ Industrial Metallurgy

32

Mineral Engineering/Mineral Dressing

33

Mining Engineering/Technology, Mining and Machinery

34

Naval Architecture/Marine Engineering

35

Oil Technology

36

Paint Technology

37

Petro-Chemical Engineering

38

Petroleum Engineering/Technology

39

Planning

40

Plastic Technology

41

Polymer Technology/Science

42

Production Engineering/Production and Management

43

Production and Industrial Engineering

44

Rubber Technology

45

Renewable Energy

46

Textile Engineering and Fibre Science

47

All other disciplines in Engineering/Technology

48

Discipline

Code

Sciences:

Applied Electronics

61

Applied Physics

62

Agricultural Science

63

Biochemistry

64

Bio-Sciences

65

Computer Applications

66

Chemistry

67

Industrial Chemistry

68

Electronics

69

Engineering Physics

70

Earth Sciences

71

Geology/ Geophysics

72

Life Sciences

73

Life Science/ Veterinary/ Animal Science

74

Life Sciences (Botany)

75

Life Sciences (Zoology)

76

Materials Science

77

Mathematics/Applied Mathematics

78

Microbiology

79

Nano Science and Technology

80

Nuclear Physics

81

Operations Research

82

Physics

83

Pharmaceutical Sciences/Pharmacy

84

Radio Physics

85

Radio Physics and Electronics

86

Statistics

87

Textile Chemistry

88

All other disciplines in Sciences