A study to evaluate the feasibility of using biodiesel fuel in U.S. Army Corps of Engineers (USACE) floating plant operations to reduce environmentally sensitive emissions, increase use of renewable energy, and reduce the use of fossil fuels was conducted with funding from the U.S. Army Corps of Engineers (USACE) Dredging Operations and Environmental Research (DOER) program and the USACE Sustainability and Energy Efficiency Program. This study was conducted by the USACE Engineer Research and Development Center (ERDC) and the USACE Marine Design Center (MDC), in conjunction with support of USACE Headquarters (HQUSACE) and participating USACE Districts. The study began in 2010 with a focus on the methodology to convert four working USACE vessels to biodiesel. Favorable results in regards to mechanical and operational issues cleared the way for evaluating biodiesel on additional vessels. Fourteen vessels were converted to biodiesel use in the expanded study, and additional tests of emissions and fuel usage were conducted on two vessels. This report describes the study that successfully demonstrated that use of certified biodiesel fuel (including biodiesel manufactured from soybeans and from algal oils) by suitable USACE floating plants is feasible to reduce select environmentally sensitive emissions, increase USACE use of renewable energy, and reduce the use of fossil fuels.