Efforts are being made to achieve environmental sustainability by combining heat and power production and exploiting renewable resources, in order to save primary energy and reduce greenhouse gas emissions. This study concerns a stand-alone 1-megawatt plant composed of a wood pyrolyzer and a combined heat and power plant based on a gas turbine. Care is devoted to saving the solid-state product of the pyrolysis reaction (biochar), both to produce agricultural fertilizer and to sequester carbon dioxide, i.e. , the emissions avoided by not burning biochar. The plant is simulated by three in-house codes: gas turbine off-design performance, pyrolysis process and time-by-time integrated plant working. A quasi steady-state, lumped parameter approach is adopted. While components models are taken from the literature, solver algorithms are partly original. In this first step of the research, a stand-alone plant with a zero-volume syngas tank is analyzed. Technical aspects alone, without considering economic or legal implications, are investigated. Our simulation suggests that there is no primary energy saving in comparison with separate heat and power systems, as shaft efficiency is too low, but that a remarkable saving in greenhouse gas emissions can be achieved.
