1. Environmental Science Chapter 18 Review Biomass fuel – organic matter burned for energy. Energy Conservation – saving energy. Energy Efficiency – percentage of energy that does useful work. Ethanol – gasoline alternative that can be made from agricultural products. Hydrogen – a clean-burning gas derived from water.

2. Environmental Science Chapter 18 Review Renewable energy – energy from sources that are constantly being formed. Wind, plant growth, and the water cycle are powered by sunlight. Fastest-growing source of energy in the world is wind power. Methane gas – by product of decomposing organic wastes.

3. Environmental Science Chapter 18 Review Hydrogen -can be burned as a fuel or used to produce electricity chemically. -is very abundant on Earth. -does not release pollutants when burned. -it is expensive. Hybrid cars -use gasoline and electricity. -are energy-efficient.

4. Environmental Science Chapter 18 Review Wind, plant growth, and the water cycle are powered by sunlight. A solar water heater uses a heat exchanger. Alternative energy -tidal power -hydrogen fuel cells (produce electricity) -burning hydrogen as fuel -ocean thermal energy conversion

5. Environmental Science Chapter 18 Review In developing countries biomass typically used for heating and cooking. In developed countries biomass is converted into methane to produce electricity. When bacteria decompose organic wastes a by product is methane gas.

6. Environmental Science Chapter 18 Review Passive solar heating – uses the sun’s energy to heat something directly, no moving parts. Active solar heating – requires moving parts, usually for pumping a liquid into solar collectors to heat it before going to a heat exchanger. Photovoltaic Cell – converts the sun’s energy into a small amount of electricity. -needs long periods of sunshine.

7. Environmental Science Chapter 18 Review Geothermal Power Plant – pumps steam/heated water from rock formation to power a turbine. Geothermal Heat Pump – uses a loop of piping that circulates a fluid underground to heat/cool homes. (55 degrees Fahrenheit) Hydroelectric Power Plant – uses the water released from a dam to flow through a turbine to generate electricity.

8. Environmental Science Chapter 18 Review Energy Efficiency = the % of energy put into a system that does useful work, (i.e. light bulb, % light, % heat given off). Energy Conservation = saving energy, using energy efficient devices.

9. Environmental Science Chapter 18 Review Essays Identify 3 ways that people can conserve energy in their daily life. Choose a form of renewable energy, and describe its advantages and disadvantages.