Cluster-ID

Cluster

Size

Silhouette

Mean (year)

0

Life history

81

0.759

2015

1

Renewable energy

66

0.619

2014

2

Energy efficiency

58

0.766

2014

3

Energy storage

53

0.653

2015

4

Oil price

47

0.676

2017

5

Power system economics

46

0.752

2015

6

Climate change

39

0.71

2016

7

Bioenergy

35

0.75

2013

8

Scenario analysis

34

0.754

2015

9

sensitivity analysis

29

0.743

2016