A new report from consulting firm McKinsey says that we could save at least $1.2 trillion by 2020 if we invest $520 billion in energy conservation. And by conservation, we're talking "smaller" improvements like fixing leaky ducts and replacing all around-the-house-or-office appliances with more energy efficient replacements.

From the press event presenting the findings:

That investment would cut the country's projected energy use in 2020 by about 23 percent - a savings that would be "greater than the total of energy consumption of Canada," said Ken Ostrowski, a senior partner in McKinsey's Atlanta office, at a press event in Washington this morning. It would also more than offset the expected growth in energy use that would be expected otherwise in the United States.

And since none of us will probably take the time to wade through the lengthy report and might be skeptical on whether or not legislation could get moving to create these possibilities, the NY Times Green Inc. blog has collected some of the "success stories" that could be modeled:

• Appliance standards: Federal energy-efficiency requirements for refrigerators, lights and other appliances have saved Americans an estimated $50 billion from 1987 through 2000, at a cost of $15 billion.

• The state of California: California's per-capita electricity usage has remained virtually stable over the past 30 years even as the nation's per-capita consumption has grown. There are many causes, but partial credit goes to the state's aggressive efficiency efforts, including setting state-level appliance standards and strict building codes.

Read More:

• McKinsey Report Cites $1.2 Trillion in Potential Savings From Energy Efficiency (New York Times)
• Solar Brokering Firm Assesses First Year (New York Times: Green Inc.)
• Success Stories in Energy Efficiency (New York Times: Green Inc.)