At the two-day meeting, Chavez will promote a project to build a 8,000km natural gas pipeline linking the Opec nation's gas reserves to countries such as Brazil and Argentina.
Chavez still wants to show unity with Lula da Silva, the Brazilian president, taking him on a tour early on Monday of a petrochemical plant and then holding discussions on ethanol, which Chavez says will increase world hunger.
Aides to Lula say it is his "obsession" despite being labeled "genocidal" by Fidel Castro, the Cuban leader and Chavez's political mentor.
"This planet is in danger, the human race is in danger"
Venezuela, the fifth-largest exporter of oil to the US, has urged Latin America to pass over ethanol and rely on its oil reserves and co-operate in developing ways to reduce energy consumption.
Power outages have traditionally blighted Margarita island, and particularly its main city Porlamar.
But with Cuban help, the government has installed millions of power-saving light bulbs in recent months that Chavez - who often speaks in apocalyptic terms about the environment - said can serve as an inspiration at the summit.
"This planet is in danger, the human race is in danger," he said after railing about high US energy demand. "Let's do what we have to do to save mankind."