Economical Evaluation of an Isolated AC Offshore Grid for Pre-salt Oil Production Based on Power Hub for Reducing Carbon Emissions

Oil and gas will still play a major role in supplying the global energy demand for the foreseeable future. Their extraction is an energy intensive sector with high level of associated greenhouse gas emissions. To address climate change concern and a carbon constrained economy, alternatives must be sought to drive the projects to new directions. For ultra-deep waters offshore activities like the ones being developed at the Brazilian pre-salt basin, located 200 km away from the coast in waters with 2,000 m depth, mature alternatives as the power from shore pose a significant engineering challenge. One alternative that can avoid weight and space restrictions on the offshore environment is the power hub. A power hub consists of a more efficient central power plant to feed partially or in total a number of offshore platforms. This paper aims at complementing previous results found in the technical literature to provide useful information for oil companies to make a full informed decisions on the adoption of a power hub. A step-by-step procedure is provided for the dimensioning and the cost estimation of such isolated AC offshore grids resulting from the power hub concept adoption. Results show that the submarine power cables are responsible for the majority of the investment and the lower cost was achieved using 66 kV for the transmission system, among the analyzed options.