annual energy outlook 1999 aeo99 assumptions to the december 1998 with projections 2020 information administration introduction 2 macroeconomic activity module 11 international 13 household expenditures 17 residential demand 18 commercial 25 industrial 33 transportation 41 electricity market 58 oil and gas supply 71 natural transmission distribution 78 petroleum 83 coal 93 renewable fuels 99 list of acronyms 112 16 1 contents t his paper presents major national modeling system nems used generate in including general features model structure concerning markets key input data parameters that are most significant formulating results detailed documentation is available a series reports synopsis components interrelationships modules presented an overview 3 were produced