This paper examines the optimisation of the Organic Rankine Cycle (ORC) systems that are fuelled by biomass to produce small-to-medium scale power. Three configurations discussed, including simple, reheated, and recuperated were tested with various organic working fluids under common biomass combustion conditions (523623 K). The maximized ORC produced a thermal efficiency of 27.38% using o xylene and m-xylene as the most effective fluids, which was much better than the simple (18.55) and reheated (19.34) configurations. A financial study revealed that the Net Present Value (NPV) of the project was positive (5.7 million pounds) with a payback period of 7.52 years provided that at least 70.77 percent of the plant hot water is sold. The fluids chosen were found to be environmentally-friendly with a low Global Warming Potential (GWP) and zero Ozone Depletion Potential (ODP). These results put biomass-ORC systems as one of the potential renewable energy sources, but issues like complexity of the system, choice of fluid, and reliance on the market to sell heat remain to be discussed.