A sustainable micro-algal biofuel process plant was hypothetically and detailed-designed for the production of value products from algae. The process plant cultures algae through controlled growth and processes; production of biomass, extraction of lipids and biofuels and refinement into finished products. The start-off feedstock was Nannochloropsis spp. and the four end products produced were bio-kerosene, methane, CO₂ and biomass slurry. The algae were grown to maturity within the least allowable possible time under controlled conditions. From an in-depth analysis of the customer specifications, concept development and selection, the study defines an overall depiction of the end products from the concepts evaluated by using the Pugh matrix and Six sigma methodologies. The process finally generates an economically viable algae biomass. This paper focuses on the process planning, criteria/concept selection, design optimization with necessary characterisations which were filtered into measurable characteristics for the design of an operable, sustainable functioning plant.