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Guillaume Decaix

Helps energy clients make significant, positive, innovative change; expert at the intersection of energy and digital sectors across the Americas, Europe, and Asia

Guillaume joined McKinsey Digital in 2004, and then worked in more than 20 countries across all heavy industries, he went back to his original passion for energy sectors and transferred to Rio de Janeiro in Brazil in 2010.

Since then, Guillaume has been helping his clients make significant, innovative changes happen. His areas of expertise are at the intersection of energy sectors, such as oil and gas, power, and renewables, as well as digital, with analytics, predictive maintenance, and new business builds. He has experience across a broad range of functions, strategy, organization, and operations, and works across the Americas, Europe, and Asia.

He leads our Latin American energy efforts, the McKinsey Digital Practice for heavy industries, and as our global AI client solutionswork. He previously led our Rio de Janeiro office for six years.

Examples of his client work include the following:

  • supporting a client to transform its capital projects business units, which had a portfolio project of $20 billion
  • setting up a predictive maintenance start-up in partnership with three companies
  • developing the strategic plan for a green hydrogen plan in Brazil
  • developing the digital roadmap for a large national oil company
  • driving a major cost-reduction and restructuring effort for a floating production storage and offloading operator
  • developing breakthrough optimization of maintenance and production—based on advanced analytics—for a full floating production storage and offloading system
  • supporting a major oil and gas company through a restructuring initiative following bankruptcy
  • supporting the top-down due-diligence efforts for investors looking to make acquisitions in oil field services, equipment, and seismic services in Latin America
  • setting up an integration office for a merger affecting more than 300,000 employees, successfully

Published work

Prediction at scale: How industry can get more value out of maintenance,” McKinsey & Company, July 2021

A Smarter Way to Digitize Maintenance and Reliability,” McKinsey & Company, April 2021

How Brazil can optimize its cost of energy,” McKinsey & Company, March 2021

Is there hidden treasure in the mining industry,” McKinsey & Company, November 2015

Hidden treasure? Low equity prices may offer important M&A opportunities for the mining industry,” McKinsey & Company, June 2015

Past experience

Consultant, purchasing


French Institute of Petroleum, IFP School
MS, economics, petroleum engineering

MSc, computer science, electrical engineering