1. What is the difference between renewable energy and alternative energy? 2. What does the phrase “energy conservation” mean to you? 3. What are the benefits of conservation? 4. What disadvantages to energy conservation can you think of?

Objectives: 1. Describe three alternative energy technologies. 2. Explain the difference between energy efficiency and energy conservation. 3. Describe two forms of energy efficient transportation.

 Def: Energy sources that are still in development  Must be shown to be cost effect to become a viable option for the future  What alternative energy sources can you think of?  Some alternative energy sources:  Tidal power  Ocean thermal energy conversion  Hydrogen

 Tides (high and low) occur twice a day.  Used 1000 years ago to power mills in France and Britain.  Used today in France, Russia, and Canada to generate electricity.  Disadvantages:  Expensive to build and maintain  Few suitable locations

 Def: using ocean temperature differences to produce electricity  Experimental power station off Hawaii  Disadvantages:  Expensive and inefficient  Environmental effects of returning large amounts of cold water to the surface?

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 Most abundant element in the universe  Does not contain carbon, so no fossil fuel-type pollutants  When burned, it produces water vapor and small amounts of nitrogen oxides.  Disadvantage: takes a lot of energy to produce

 Def: produces electricity chemically, like a battery, by combining hydrogen fuel and oxygen  The only by-product (or waste) is water.  Hydrogen can be obtained from alcohol, natural gas, or gasoline.

 Electricity from bacteria  Read “Science & Technology”, p.479.  Water pumps and seesaws in Columbia  Human-powered washing machines

 Def: the percentage of energy put into a system that does useful work  Energy efficiency (in %) = energy in/energy out x 100  Overall, more than 40% of all energy used in the U.S. is wasted.  Some solutions are simple: better insulation, fluorescent light bulbs. Others require sacrifice or new technology.

 Hybrid cars  Use a small, efficient gasoline engine most of the time  Also use an electric motor when extra power is needed  Convert some of the energy of braking into electricity and store it in the battery  Gasoline engine shuts off when car is stopped at a red light

 Def: saving energy  Using more efficient devices  Wasting less energy  Some cities offer incentives  How can we conserve energy around the home?  In daily life?

 Wash clothes in cold water