Integrated Science C Mrs. Brostrom

 Describe the availability, current uses and environmental issues related to the use of hydrogen fuel cells, wind and solar energy to produce electricity.  Describe human efforts to reduce the consumption of raw materials and improve air and water quality.

 How will society meet growing energy demands in a sustainable manner?  Fossil-fuels currently supply ~80% of world energy demand.  Only about 50 years left for fossil fuels if we use as current rates

 Nuclear Energy  Solar Energy  Hydroelectric Energy  Wind Energy  Wave Farms  Biomass  Geothermal Energy  Hydrogen Fuel Cells

 Energy received from the sun in the form of radiation  Renewable resource  Can be used to heat homes, generate electricity  Photovoltaic cells  Solar cells  Solar collectors

 Solar collectors are dark colored boxes that have glass or plastic tops used to heat water in pipes running through it   Photovoltaic cells are an electrical device that converts the energy of light directly into electricity by the photovoltaic effect

 Not all parts of Earth get the same amount of sunlight  Solar farms located in desert/high intensity/long sunlight hours  Parabolic mirrors reflect/focus sun’s rays onto metal water pipe located along focal axis of mirrors.  High temperature produced

 Advantages:  doesn’t pollute air or water  Renewable resource  Disadvantages  Weather- clouds  Time of day- night  Expensive- but there are many programs to subsidize costs

 Falling water releases energy  Depends on sunlight  Rivers are created through the processes of the water cycle  Energy is harnessed by dams  Create large holding places for water  Falling water pours through turbines and makes them spin  Turbines are connected to generators that produce energy

 Renewable resource  Advance sin technology could make energy generation more efficient at existing dams  Dams can alter a river’s flood and erosion pattern  Most big rivers have dams already  Little potential for expansion

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 Indirectly connected to solar energy because wind is caused by unequal heating of air  Windmill drives an electric generator

 Larger average wind speed than onshore  Easier planning consent  Technical expertise exists from oil rig experience  Suitable location /watch?v=K6BkPmKBJ9Y 1:56

Advantages:  Renewable resource  No pollution  Low cost Disadvantages:  Wind can be unreliable  Bird/bat kills  Disruption of marine floor habitat- offshore  Eye sore- not in my backyard

 Energy generated from the combustion of plant material and animal waste  In CT, all of trash is combusted at trash to energy facilities  Ethanol  Fuel made from corn or sugar  All gasoline contains 10% ethanol  Biodiesel  Made by transforming animal fat or vegetable oil with alcohol.  Fuel is made from rapeseed (canola) oil, soybean oil, or recycled restaurant grease.  Directly substituted for diesel either as fuel or as an oxygenate additive

Advantages:  Renewable resource  Reduction of waste  Extremely low emission of greenhouse gases compared to fossil fuels  Ethanol is Carbon neutral and forms a part of the carbon cycle  Growing variety of crops increases bio-diversity Disadvantages:  Biomass processing technologies and biofuels use have the potential to increase emissions of ozone precursors  Increase in NO x emissions  Excessive inhalation of ethanol is harmful  Burning biomass deprives local eco-systems of nutrients  Increased use of pesticides and fertilizers to produce energy crops contaminate ground and surface water

Geothermal energy is produced from reservoirs of hot water and steam under the Earth's crust. Beds of molten magma heat water or steam Wells are drilled ad the steam rises Turning a turbine to generate electric power Major source of energy in volcanic areas New Zealand, Iceland, California

Advantages:  No air pollution  Easy to harness when magma beds are close to the surface Disadvantages  Use of this resource is limited due to lack of magma beds close to the surface

 A fuel cell is a device that converts the chemical from a fuel into electricity through a chemical reaction with oxygen  Chemicals constantly flow into the cell so it never goes dead  Use hydrogen and oxygen as the chemicals  1:45

Advantages:  Most abundant element on Earth  No harmful emissions  Efficient- more energy for less fuel  Renewable resource Disadvantages:  Needs fossil fuels to break apart H from O  Expensive  Hard to transport  No existing infrastructure to support H fuel  Highly flammable