WASHINGTON, D.C. --- At a major energy conference last week, leading executives of BP and General Motors were among the speakers who highlighted the potential role that hydrogen will play in powering vehicles of the future, CNNMoney.com reported.

The Washington International Renewable Energy Conference, organized by the U.S. State Department, focused on ways to cut greenhouse gas emissions in half by 2050 during a time of global economic growth.

Several industry experts predicted that hydrogen would probably fuel the cars of the future, but the technology needed about 50 years of development. In the meantime, companies will continue to pursue other strategies as well.

Robert Babik, director of emissions, environment, energy and safety policy at General Motors, discussed the electric Chevy Volt and the E-Flex design concept. The E-Flex is a vehicle equipped with an electric motor and an on-board electricity generator capable of charging the batteries on long trips or when an electrical outlet isn't accessible.

Jim Hossack, a consultant for research firm AutoPacific, praised GM's efforts in developing vehicles running on a variety of fuels --- hybrid vehicles as well as vehicles running on diesel, electricity and hydrogen.

BP Chief Executive Tony Hayward advocated for developed nations to enact carbon emission controls regardless of what China or India does. He also pushed for government subsidies to help jumpstart emerging energy technologies. He added that BP is working to develop biofuels from non-food crops.

Also at the conference, U.S. Energy Secretary Samuel Bodman praised the private sector's investment in clean energy, which has jumped from $500 million in 2005 to more than $2 billion in 2007, CNNMoney.com reported.