Energy policy 363 Power resources 96 Environmental aspects 57 Renewable energy sources 46 Government policy 45 Energy consumption 42 Petroleum industry and trade 37 Energy conservation 36 Energy development 34 Environmental policy 31 Energy industries 29 Political aspects 26 Economic aspects 23 Foreign relations 21 Climatic changes 19 History 18 Energy security 13 Forecasting 13 Petroleum reserves 13 Politics and government 13 National security 12 Social aspects 12 Sustainable development 12 International cooperation 11 Economic policy 9 Research 9 Biomass energy 8 Economic development 8 Foreign economic relations 8 Greenhouse gas mitigation 8