Technology: general issues 281 History of engineering and technology 255 Power 166 Research & information: general 120 Electric power transmission networks 106 Wind power 91 Solar power generation 82 History of engineering & technology 73 human 73 Energy efficiency 70 Energy 60 Renewable energies 60 Solar energy 59 Costs 54 Power generation & distribution 52 Humans 51 Energy utilization 48 Internet of things 47 Physics 46 Electric power utilization 43 Performance 43 Efficiency 42 Forecasting 42 MATLAB 42 article 42 Optimization 39 Renewable energy resources 39 Research and information: general 38 Solar cells 38 Energy harvesting 37