The objective of this PhD project is to support a sustainable production of protein feed from grass by Green Protein Plant. The grass protein production is challenged in order to make a truly sustainable business case. Adding pyrolysis technology will result in production of both renewable energy and biochar. The produced energy will be integrated with the protein separation process and cover the internal energy demand of Green Protein plant. This will make the production independent of fossil energy and reduce the energy costs. The biochar, which is expected to be low in ash and thus of high quality, has potential high value market applications as toxin binder in the feed industry and as pollutant remover. Adding an extra high value product to the green biorefinery concept as well as reducing dependence on fossil energy will improve the economics and sustainability of green protein production and make it a viable business case.