Bio-power and biofuels are promising alternative energy resources. This paper investigates their role in the long-term U.S. national energy and transportation portfolio planning, while considering the competition among other energy options. The paper presents a systematic modeling framework for integrating biomass pathways to the energy and transportation systems, and also captures the geographical variation in the feedstock availability and cost across the U.S. The paper then presents two different case studies-energy sector planning and integrated energy & transportation sectors planning. The studies reveal long-term cost and emission savings from bio-renewables, where the bulk of benefits are observed due to biofuels (with bio-power production limited by feedstock prices). Under a 40% CO2 emissions reduction scenario over the next 40 years, penetration of bio-renewables promise up to 10-Trillion USD (2010$) savings in system costs (investments and operational). Simulations also show that the impediment with bio-renewable penetration is mostly influenced by the availability of low-cost feedstock, specifically for bio-power production. According to current estimation of long-term feedstock availability, U.S will be able to power upto 150 Billion Gallons Year (BGY) (or approx. 560*10(9) L per year) bio-refinery capacity around 2020s, and about 200 BGY (or approx. 750*10(9) L per year) by 2050. (C) 2016 Elsevier Ltd. All rights reserved.