The U.S. forest and agriculture sectors have the capacity to provide biomass feedstocks to contribute to renewable electricity standards meeting 10% and 20% of anticipated future U.S. elec- tricity consumption. In our model, when the forest and agricul- ture sectors can compete to provide biomass and for land, both sectors contribute biomass to meet bioelectricity needs. Because of ready availability, we project that the forest sector would be the primary initial provider of biomass feedstock, mostly logging residues. Over time and with increased demands, we project that the agriculture sector would provide the majority of biomass feedstock via energy crops and some crop residues. The relative preference for agriculture sector feedstocks is consistent with (1) that sector’s ability to produce higher biomass energy yields per unit of land area and (2) the shorter period of time for agriculture biomass crops to reach maturity.