Written by Jennifer KhoAt a speech in San Francisco on Wednesday, Google ( GOOG) CEO Eric Schmidt proposed a new energy plan for the U.S. that the company claims could reduce fossil fuel-based energy generation by 88 percent. The plan calls for the replacement of all coal- and oil-fired electricity generation with natural gas and renewable electricity, including a whopping 380 gigawatts of wind power, 250 gigawatts of solar power and 80 gigawatts of geothermal power. Other elements of the plan include reducing energy use 33 percent via energy-efficiency measures, boosting sales of plug-in hybrid vehicles to 90 percent of new car sales in 2030, increasing the average fuel efficiency of conventional vehicles from 31 miles per gallon to 45 miles per gallon in 2030 and turning over the country's current fleet of vehicles more quickly so that cars are driven only 13 years, instead of an average of 19 years today. The goals are ambitious, to say the least. The company said it would require a number of new policies, including a long-term national commitment to renewable electricity -- not a minor feat considering the Congress hasn't yet been able to pass a multiyear extension of tax credits for renewable energy after months of effort. It would also require increased transmission capacity, a "smart" electricity grid to better monitor and manage energy use, and higher fuel-efficiency standards for vehicles. The plan would cost plenty of cash. According to Google, the cost of the proposal -- called Clean Energy 2030 -- is a hair-raising $4.4 trillion dollars. But the company is also quick to point out that the investment will result in even greater savings of $5.4 trillion over the 22-year life of the plan, according to Google's calculations. "We see a huge opportunity for the nation to confront our energy challenges," wrote Dan Reicher and Jeffrey Greenblatt, both of Google.org, in a blog post Wednesday. "In the process we will stimulate investment, create jobs, empower consumers and, by the way, help address climate change." The plan is not the first to attempt to solve the country's energy challenges. Texas oilman T. Boone Pickens and former U.S. vice president Al Gore also have suggested their own proposals for solving the problem.