 By 1986 she joined a small group within Enron developing cogeneration and independent power plants using natural gas.After a two-year stint working part-time for Enron while attending Harvard Business School, she returned to Houston and became head of the newly formed Enron Development Corp. in 1991, developing and building power assets in North America and internationally.As Enron grew, Mark was responsible for its global power and pipeline assets outside of North America.