You've seen the ads by BP (formerly British Petroleum), Chevron and other oil companies, bragging about their commitment to move "beyond petroleum" by developing new sources of clean, renewable energy. With its enormous financial assets, record profits and technological expertise, could Big Oil lead us to a clean energy future?

Don't hold your breath (unless you live near a refinery). The New York Times reports that even as the Obama administration puts its weight behind "the most ambitious transformation of energy policy in a generation," many oil companies are failing to back their greenwashing with greenbacks.

Royal Dutch Shell said last month that it would freeze its research and investments in wind, solar and hydrogen power, and focus its alternative energy efforts on biofuels. The company had already sold much of its solar business and pulled out of a project last year to build the largest offshore wind farm, near London.

BP, a company that has spent nine years saying it was moving "beyond petroleum," has been getting back to petroleum since 2007, paring back its renewable program. And American oil companies, which all along have been more skeptical of alternative energy than their European counterparts, are studiously ignoring the new messages coming from Washington.

"In my view, nothing has really changed," Rex W. Tillerson, the chief executive of Exxon Mobil, said after the election of President Obama.

The Times reports that despite their green posturing, the overwhelming bulk of Big Oil's investments still go to dirty energy, including hyper-polluting sources like tar sands or shale. Investments in alternative energy are so small, says one analyst, it's hard to find them in the companies' portfolios:

In the last 15 years, the top five oil companies have spent around $5 billion to develop sources of renewable energy ... This represents only 10 percent of the roughly $50 billion funneled into the clean-energy sector by venture capital funds and corporate investors during that period.

Got that? The same visionary investors who bet on the Internet, and won big, are now bankrolling most of the research into clean energy. Meanwhile, Big Oil is doing what it's always done: Trying to squeeze as much profit out of fossil fuels as it can, and damn the cost of global warming and air pollution.