The stimulus plan increasingly appears unlikely to include major investments in so-called "green infrastructure" _ the wires and rails that could deliver renewable energy to Americans' homes and help them kick their gasoline addictions _ according to alternative-energy advocates who are discussing the plans with the Obama transition team.

It's a timing issue. The blueprints and, in many cases, the authority simply don't exist to lay miles of high-speed rail lines, or to build a sprawling web of new power lines to create a truly national electric grid.

"Before you spend billions of dollars on new lines, you have to spend millions of dollars on design work," said Michael Moynihan, the green project director of the liberal think tank NDN, who has worked extensively on green infrastructure and the stimulus. "Nobody had been thinking about this much money (becoming available). So the planning just has not been done."

Obama spokesman Amy Brundage stressed the president-elect's commitment to green infrastructure on Tuesday but did not disclose stimulus details.

"President-elect Obama is committed to making sure we are moving forward with Smart Grid projects and mass transit initiatives that will spur long-term growth in our economy," she said. "Clean energy and infrastructure are top priorities in an American Recovery and Reinvestment Plan, and President-elect Obama's team is working to make these essential investments to create jobs and help put our economy back on track."

The United States now uses a series of regional power grids that make it impossible for a wind farm in Texas to send electricity to a skyscraper in New York. Advocates say that could change under a vastly expanded national grid, opening markets for wind, solar and other energy alternatives.

Obama has pledged to invest in green infrastructure as part of his push to reduce American dependence on oil imports. At a Senate confirmation hearing on Tuesday, his energy secretary nominee, Nobel Prize-winning physicist Steven Chu, called a nationwide grid "in the national interest" and said the country needs a "new way of doing business" to get it built quickly.

Chu also acknowledged the biggest obstacle: the question of where those new power lines would go. States, municipalities and landowners have cried foul over plans to string transmission networks through their backyards; at Chu's hearing, Sen.