When a blackout shuts down a factory, the impact isn't apparent to the public. But lose power at an international airport, and thousands of angry travelers and the people waiting for them won't be interested in excuses. The Greater Toronto Airports Authority learned that lesson in August 2003. Ten months later, it began building a 117-MW cogeneration plant that is now capable of supplying all of its energy needs-not just electricity, but space heating and chilled water as well.