"Solar Power International 2009" is expected to draw more than 25,000 visitors from 90 countries.
650 solar energy companies are on hand, marketing their products. They include solar hot water, solar heating and cooling and solar pool heating. The event also features more than 65 education sessions.
Actor and activist Ed Begley, Jr., Secretary of Labor Hilda Solis and environmentalist Robert Kennedy, Jr. were just some of Wednesday's featured speakers.
The expo continues through Friday.
