Subject
energy supply
55
energy demand
34
energy economy
34
energy
32
electricity
25
energy statistics
24
world energy consumption
23
petroleum
20
building
18
gas
18
mining
17
petrochemical industry
17
energy consumption
16
energy planning
15
electric power supply
12
environmental protection
12
petrochemistry
12
renewable energy
10
electric power generation
9
energy conservation
9
energy policy
9
new federal country
8
renewable energy source
8
sustainable development
8
energy technology
7
electric power consumption
6
energy production
6
old federal country
6
coal
5
energy conversion
5
energy management
5
heating system
5
wind energy
5
cogeneration
4
development
4
energy resource
4
energy transport
4
fossil fuel
4
methanol
4
natural gas supply
4
solar energy
4
OECD countries
3
alcohol
3
climatic change
3
combined cycle power plant
3
electric power industry
3
electrical engineering
3
energy analysis
3
energy efficiency
3
energy environment balance
3
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