Natural gas has gotten a boost from U.S. President Barack Obama's energy speech this week.

"The potential for natural gas is enormous," Obama said, noting that the United States has perhaps a century's worth of shale reserves.

"Last year, more than 150 members of Congress from both sides of the aisle produced legislation providing incentives to use clean-burning natural gas in our vehicles instead of oil … and that's a big deal," Obama said.

The president was referring to the NAT GAS Act, scheduled to be introduced in Congress next week, which aims to boost the use of natural gas as a fuel in the transportation sector.

In his speech Obama cited billionaire oilman T. Boone Pickens as a backer of the legislation. Pickens is author of the Pickens Plan, aimed at weaning the country off foreign oil, part of which is included in the NAT GAS Act.

"It is clear President Obama is committed to weaning America off Middle Eastern oil, securing our own energy future and recognizes the role natural gas can play as a domestic transportation fuel," Pickens said in a statement following the president's speech.

Pickens has much to gain if the legislation passes. He is the largest shareholder in California company Clean Energy Fuels, which owns and operates 200 natural gas refueling stations across the nation.

Clean Energy also owns BAF Technologies Inc., a Dallas company that converts vehicles to run on natural gas. And Pickens owns mineral rights on 156,000 acres in Pennsylvania and West Virginia and 30,000 acres in Oklahoma and Texas, he told reporters Wednesday, The Dallas Morning News reports.

Still, Obama expressed concern about the potential environmental impact of gas drilling -- or hydraulic fracturing -- on underground water supplies, saying he has asked Energy Secretary Steven Chu to work with other agencies, the natural gas industry, states and environmental experts "to improve the safety of this process."

Approximately 110,000 natural gas vehicles are on U.S. roads today, with more than 12 million in use worldwide, says the Natural Gas Vehicles for America, a Washington trade group.

While vehicles running on compressed natural gas get about 20 percent lower fuel mileage than diesel engines, carbon dioxide emissions are about 25 percent less and about 90 percent less smog-producing emissions, Bernstein Research says.

On Wednesday, the U.S. Environmental Protection Agency also issued a rule that eases the conversion of after-market cars and trucks to compressed natural gas and other alternative fuels.