During the 2008 presidential campaign, Barack Obama promised to "create a federal Renewable Portfolio Standard (RPS) that will require 25 percent of American electricity be derived from renewable sources by 2025."

As we previously noted, in June 2009, the U.S. House of Representatives, then controlled by the Democrats, narrowly passed a cap-and-trade bill. The legislation required that 20 percent of electricity come from renewable sources by 2020 -- a standard similar to what Obama had promised. However, neither this bill nor any other bills were brought to a vote on the Senate floor, and all expired at the end of the 111th Congress.
   
Obama did reiterate the goal in his 2011 State of the Union address, saying that by 2035, 80 percent of America's electricity will come from clean energy sources. "Some folks want wind and solar. Others want nuclear, clean coal and natural gas," he said. "To meet this goal, we will need them all."
   
But with the advent of the 112th Congress, Republicans took control of the House with a focus on deregulation and an opposition to cap-and-trade programs. Any cap-and-trade bill was dead on arrival in the chamber that had approved it in 2009. And no one expects passage of a cap-and-trade bill in the post-election, or "lame duck," Congress.

We'll add one slight nuance, however. While Obama has failed to pass legislation to mandate that 25 percent of American electricity be derived from renewable sources by 2025, it's a lot more plausible now than it was in 2008 that the nation could approach that goal without a legislative mandate.

According to the Energy Information Administration, the federal government's office for energy statistics, non-hydropower renewable energy is poised to increase from 2 percent of total generation to 6.7 percent between 2010 and 2025, while hydropower -- a more traditional form of renewable energy than solar or wind -- is set to increase from 10 percent to 14 percent over the same period. That would bring renewable sources to 21 percent by 2025.

It's possible to "distinguish between a policy failure -- an inability to enact a national renewable portfolio standard -- and an empirical target, which can have a momentum of its own," said Joel Darmstadter, a senior fellow at Resources for the Future, an energy and environment think tank.

Another factor that wasn't fully appreciated at the time Obama made the promise was rapid growth in the domestic production of natural gas. Despite environmental concerns about the extraction process known as "fracking," natural gas is a relatively clean-burning source of electric generation and has taken some of the pressure off the need to turn to new-generation renewable energy sources.

"Low-priced natural gas has blunted the momentum toward the use of renewable energy in the electric-power sector," said Stephen Brown, director of the Center for Business and Economic Research at the University of Nevada, Las Vegas. "When low-priced natural gas displaces coal, it offsets carbon dioxide emissions. Low-priced natural gas is a game-changing phenomenon that was not expected in 2008."

Still, both the expected growth in renewable energy and the expansion of domestic natural gas production are ultimately side issues when judging Obama's progress on his promise. He said he would enact a law to "require 25 percent of American electricity be derived from renewable sources by 2025," and he has not done so during his first term. So we're calling it a Promise Broken.