External Power Supply for Ultra-Deep Water O&G Assets: Synergies, Scale Effects and Challenges

Abstract

Abstract A dramatic reduction of greenhouse gas emissions in offshore oil and gas production facilities in the coming decades is foreseen, which will require profound changes in offshore electrical power supply. In this paper, several scenarios comprising offshore oil & gas production facilities were analyzed in terms of fluid production curves and primary processing plants schemes, so that power and heat demand are estimated. Assuming that heat remains supplied through simple-cycle gas turbines with waste heat recovery units like existing facilities, power importing margins were determined for optimum heat recovery in a number of offshore assets. Three low-carbon external power supply options were investigated: (i) Power from shore; (ii) Offshore power generation with post-combustion carbon capture and storage (CCUS) and (iii) Floating offshore wind. Results are analyzed in terms of technical feasibility, economic indicators and emissions reduction potential. The present study consists in evaluating and comparing the LCOE (Levelized Cost of Electricity) and emissions reduction of offshore oil and gas projects with power import alternatives. Practical limitations for implementation in brownfields for each scenario are discussed when presenting the challenges that must be faced. Scenarios comprising a wide range of external power supply capacity, and consequently many power import systems, were analyzed and compared. With production units far from the coast, importing power from the national grid may require a lower LCOE than implementing a power hub with CCUS, according to the results of this study, but the required investments (CAPEX and OPEX) are substantial, especially in brownfield projects where the upgrade to external power supply would be redundant with the already existing power generation system of the offshore facility. Additionally, floating offshore wind alternative, in turn, has restrictions because of the intermittent generation and relatively low capacity factor. Nevertheless, the results present some insights regarding the intercomparison among all alternatives to large scale offshore hubs connected to multiple offshore assets. Despite external power supply alternatives requiring substantially higher costs, it is expected for these costs to reduce in the near future with standardization of the required technologies. This trend can unlock opportunities to provide energy to additional subsea Processing & boosting, which may be the key to accelerate the adoption of external and low carbon power supply of O&G assets.