Eco-efficiency of power supply systems for offshore platforms

This study compared from an Eco-efficiency point of view three electricity supply alternatives for oil and gas extraction, preliminary treatment, and distribution activities that occur on floating production, storage, and offloading platforms (FPSO) operated off the coast of Brazil. The performance of autonomous systems (AS), in which independent open-cycle gas turbines generate electricity, was confronted with those achieved, respectively, by a Power Hub (PH) system and by an arrangement that associates the Power Hub system with an offshore wind farm (PHWE). The environmental dimension of the Eco-efficiency indicator was specified based on applying the Life Cycle Assessment technique for the impact categories of Global Warming Potential, Primary Energy Demand, and Fine Particulate Matter Formation. The economic dimension followed a similar approach based on Life Cycle costing (LCC) when considering the same units' construction, operation, maintenance, and dismantling costs. Given the characteristics of Brazilian oil fields, a comparison was made for three different stages of the operation cycle: C1: maximum extraction of oil and gas; C2: equity of volumes extracted from fuels and water + CO2; and C3: minimal extraction, but economically viable, of fuels. The results indicated that the PH and PHWE systems accumulate better environmental performance than the AS system, particularly regarding Global Warming Potential (35 % and 55 %, respectively) and Fine Particle Matter Formation (47 % and 59 % reduction). However, more than these gains are needed to compensate for the same systems' construction, operation, and maintenance investments, which were increased by up to 76 % in the case of PHWE. The study also concluded that the PH technology and its variation involving wind electrification are promising but that research efforts should be made to reduce costs. These results provide elements that can both subsidize designers from O&G companies in developing new extraction technologies and support decision processes conducted by other stakeholders and policy formulators linked to this segment.