Alternate Energy Sources, part II

Transcription

1 Alternate Energy Sources, part II FIGURE V01_T1: Bird kills from commercial wind turbines Tidal Power Rise and fall of water used to move turbines, producing electricity Clean energy no water or air pollution Reliable occurs daily 1

2 Harness the energy by building a dam or closure at the opening of a bay or estuary As water passes through opening moves turbines Interferes with movement of silt and water Less intrusive submerged turbines that don t interfere with silt and water movement Location Need areas with substantial tidal range Gulf Coast region: 1-3 feet tidal range Alaska, Canada (Bay of Fundy), Russia, Philippines have good tidal ranges 2

3 Current operation France operating plant in northern France since 1966 Generates 1/5 th the energy of regular plant Smaller plants in Nova Scotia and Russia Advantages /Disadvantages Harvesting renewable energy No pollution Limited to coastal areas with high tidal ranges Population concentration and tidal areas may not be in same place Interferes with ecosystem Some indication of increased red tides Blocks silt transport Geothermal power Hot water used as energy heat homes, generate electricity Clean energy Typically near tectonic plate boundaries 3

4 Hot water Hot water used in homes Heat from hot water used to heat homes Water needs to be hot, not steam Wells drilled into ground Iceland 65% homes heated this way at ¼ cost of traditional methods (oil, coal) Steam Rocks, heated from pressure and nearby magma, convert water into steam Steam moves turbines Limitation on steam: takes a while to heat rocks Is an endless resource Pressure of steam may fall over time 4

5 Steam-generating plants California: currently generating 40% of world geothermal energy The Geysers began in early 1960s Geysers Geothermal area - world's largest dry-steam geothermal steam field Generates electricity for >2.5 million people Production has fallen in last 10 years Advantages/disadvantages Relatively cheap electricity Low emissions Domestic production Limited number of locations Can be a local (small) operation With steam comes other gases (hydrogen sulfide) and odor In hot water, minerals that can corrode pipes Subsidence (1 ½ feet per year in New Zealand) no record of it in California Biomass 20% of world s energy use Primarily in less developed countries Not necessarily a clean resource But adds less carbon dioxide to the atmosphere than fossil fuels Biomass plant material or material made from plant material 5

6 Types of biomass 1. Fuelwood Wood or wood products Burn for home heating and cooking Best for local consumption Home heating in US Resource as cooking typical in less developed countries Types of biomass Fuelwood: high emissions (releases carbon into atmosphere) Can create a health hazard in the winter - inversions NOT A CLEAN energy Types of biomass 2. Solid waste burning Burnable organic waste (trash) Electricity and heat can be generated Waste material separated into burnable and non-burnable Efficient use requires large volume and dependable supply 6

7 Types of biomass Solid Waste burning: Reduces amount of trash in landfill Expensive to operate unless cost of waste disposal is included separating trash expensive Switzerland burns 75% of waste vs. 35% in US Not a CLEAN energy but it is a way to reduce landfill mass Types of biomass 3. Landfill methane production Decomposing organic matter naturally gives off methane Methane Natural gas used for energy generation Also an air pollutant when released into atmosphere Landfill methane serves two causes energy generation and reduction of air pollution 7

8 Types of biomass Landfill methane production Over 50 operating methane projects in US Most popular in Northeast Type of garbage impacts amount of methane produced with wet, organic rich matter the best Best in regions with a climate that hastens decomposition At odds with solid waste burning Types of biomass 4. Energy plantations crops used as fuel Currently big producer of fuel but not electricity Need: High crop yield Ability to produce high amount of energy Large scale production: Ethanol Biodiesel 8

9 Ethanol Produced from sugar, starch or cellulose (all plant material) Corn typically used, but sugar beets, sorghum also used Burns cleaner than oil or gas but not necessarily better 100% grain alcohol Method for extraction Corn ground into powder Mixed with water (3.5 gallons of water for every 1 gallon of ethanol) Enzyme and yeast added and mixture is heated to aid in fermentation Distillation removes everything but pure alcohol Location Refinery plants need to be near grain (keep costs down) Also need water Proximity to cattle and hog farms keep costs low 9

10 Production 15% of corn crop in US becomes ethanol 1.6 million bushels of a 11.1 billion bushel crop 1 bushel of corn becomes 2.8 gallons of ethanol Production increasing part of federal mandate to increase alternative fuels Refuse 70% of corn kernel used in production of ethanol Remaining portion contains high protein Used for cattle and hog feed (called Dry Distillers Grain) 10

11 Uses: E10 Currently not used alone but added to unleaded gas: E10: 10% ethanol and 90% unleaded gas Can be used in all gas-operated cars today without modification Burns slightly less efficiently Cannot be transported in pipelines, but rather through trucks, barges, and railcars Easily picks up excess water and impurities Other uses Ethanol added above 10% not warranted by car companies E85: 85% ethanol, 15% unleaded gas Alternative fuel Can be used in flex fuel cars World ethanol producers Brazil largest user of ethanol and lower cost producer Cars in Brazil use high ethanol content Not cost-effective to import ethanol because of tariffs imposed by federal government 11

12 Advantages Produced domestically Low emissions Lowers oil consumption Potential for future uses tremendous Disadvantages Resultant fuel is not cheaper to consumers Critics: Increases food prices and food unavailable to masses Increased demand of corn Farmers pay more for corn to feed to animals increased prices of milk, cheese, beef, etc. Tax credits and import tariffs make actual cost different to discern Biodiesel Alternative fuel for diesel engines Diesel engines those that run on diesel fuel (a heavier fuel) Higher emissions and pollutants Heavy duty vehicles Engines last longer 12

13 What is biodiesel? Not just vegetable oil Oils and grease Typically soybean oil and yellow grease (recycled cooking oil) Other plant oils work as well Replace yellow grease with animal oil (exp: lard) Biodiesel Cleaner than diesel Produced domestically Like ethanol, can be combined with diesel Production 20 million gallons commercially produced each year Not seen as diesel replacement but extender or additive B20: 20% biodiesel and 80% diesel Use in most diesel engines Lower fuel mileage Lower engine performance 13

14 Advantages Reduces emissions: lowers air pollutants Renewable Domestically produced Recycles used grease Extend engine life? Advantages/disadvantages Replaces a portion of a nonrenewable energy Can be cheaper 10% reduction in fuel mileage and engine performance Also a food source: potential for increased prices Not as big of a polarizing topic as ethanol 14

15 Hydrogen Great potential as an energy source Need electricity to produce hydrogen gas: Heat water to high temperature or pass electrical current through it Clean energy Fuel cells store energy created by hydrogen Use in vehicles Future directions Employment opportunities provided by different types of energy 15