The United States is the world's largest consumer of energy. We use electricity, gas and oil to light and heat our buildings and run our cars. The demand for power is growing. But we may not need to build new power plants or find more oil. The best way to increase our supply of energy is to be more efficient. Did you know that when you leave your video-game console   on, it consumes more electricity than two refrigerators? Or that those funny-looking, twisty bulbs   use 75% less power than traditional light bulbs? We have the tools to save money, reduce pollution and even help our planet, simply by wasting less energy. As President, Barack Obama plans to make energy efficiency in American a major goal. He has promised to cut 15% of all energy used by the Federal Government. In a speech, he called for 75% of government office buildings to be updated for better efficiency. He pointed out that energy-efficient buildings and homes will save consumers billions of dollars on energy bills. An "extra benefit", he added, will be "a cleaner, safer planet." Gas, coal and oil are called fossil fuels. Fossil fuels have been the world's main source of energy for hundreds of years. But burning them releases dirty gases, which cause pollution. There are two main ways to save energy. The first is to use more efficient machines. Hybrid cars use less gas. New appliances are designed to use less electricity. Today's refrigerators are three times more efficient than those before 1973. Laptop computers consume much less energy than desktop computers. The second is to use machines more productively. According to the US Department of Energy, in the average home, 75% of the electricity used to power electronic equipment is standby power   . That means power flowing to plugged-in appliances whether or not they are being used. Homeowners can avoid wasting power by pulling the plug on appliances when they are not in use. Efficiency experts argue that today's best techniques could cut US oil and gas use in half, and reduce our electricity use by three-fourths. By referring to Obama's plan, the author mainly intended to say that   _
the US government office buildings have wasted the most energy Obama has decided to take the lead to cut down the use of electricity it is time for the US to shoulder the responsibility for a cleaner planet the US is determined to improve energy efficiency in the whole America