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Lecture #9 - Alternative Energy and Green Technologies

 

Substitutes for Transportation Fuels

 

1. Economics of Biofuels

  • Biofuels are made from agricultural sources and are added to transportation fuels
  • Petroleum is refined into gasoline and diesel fuel
    • Completely different source
  • Biofuels cost more than their respective fossil fuel source
    • If they were cheaper, we would be using them
    • Usually subsidized by governments of developed countries
  • Analysis is similar to recycled materials

Market for biofuels

  • Similar to recycled materials, the demand has to be high for market to supply biofuels
  • Government uses mandates to force petroleum refiners to blend a percentage of biofuels into the petroleum fuel
  • Transportation fuels market
    • Supply - petroleum and biofuels refineries
    • Demand - car drivers
      • Market Price is PT
      • Market Quantity is QT

Biofuels Market

  • In theory, petroleum refineries can lower their production level
    • They decrease their demand for petroleum
      • Both market price and quantity decreases
  • Biorefineries increase their demand for agricultural feedstocks
    • Feedstocks can also be made into food for the people or animal feeds
    • A strong biofuel industry will increase vegetable prices and increase production
    • Some claim biofuels are a backstop technology
      • This is debatable

Biofuel's impact on the Agriculture and Petroleum Markets

 

2. Ethanol - substitutes for gasoline

  • Sources for the United States
    1. Sugar crops - sugar beets, sugarcane, and sweet sorghum
      • Sugar is fermented into ethanol using yeast
      • Opportunity costs
        • Diverts commodities from the human food and animal feed markets
        • Some crops and commodities are exported, like sugar
          • Could worsen a trade deficit
    2. Starch crops - corn, rice, wheat, potatoes, barley, etc.
      • Starch is long chains of sugar
        • Use acids or enzymes to break starch down into sugars
        • Yeast ferments sugars into ethanol
      • Opportunity costs
        • Diverts commodities from the human food and animal feed markets
        • Some crops are exported
          • Could worsen a trade deficit
    3. Energy crops - fast growing perennials that can be converted to ethanol
      • Switchgrass, willow, and hybrid poplar
      • Called lignocellulosic fermentation
        • Experimental
        • Break down into five types of sugar
          • Requires multiple processing stages
          • Requires different types of organisms
          • Has higher capital costs
      • Opportunity costs
        • Land could be used to grow food and vegetables for people and animals
        • Energy crops could be burned with coal to generate electricity
    4. Agricultural residues
      • All crops leave behind residues
      • Uses lignocellulosic fermentation
        • Same process as energy crops
      • Opportunity costs
        • Crop residues provide surface cover
          • Adds organic material and nutrient to the soil
          • Prevent soil erosion
          • Companies would be limited in how much could be removed
      • Could be burned with coal to generate electricity
    5. Wood residues
      • Saw mills generate many residues like sawdust and wood chips
        • Use lignocellulosic fermentation to convert to ethanol
      • Opportunity costs
        • Could be burned with coal to generate electricity
        • Wood chips and residues are used in particle boards, paper, cardboard, etc.
  • Benefits
    • Contains 36% oxygen - burns cleaner than gasoline
      • Gasoline contains almost no oxygen
      • Tail pipe emissions are cleaner
      • EPA requires petroleum distributors to add oxygenates to fuel for cities with ozone or carbon monoxide problems
    • Recycles carbon dioxide from the atmosphere
      • Plants and trees remove carbon dioxide from atmosphere
      • Carbon is store in plants
      • Plants are processed into fuels
      • Fuels are burned and carbon is released back into atmosphere
        • Carbon recycling is not 100% efficient
        • Fossil fuels are used to grow and process fuels
      • Thus, wide-scale use of ethanol could greatly slow down greenhouse gas emissions into atmosphere
    • Increases incomes for farmers
      • Causes higher prices for agricultural commodities
    • Reduced imports of petroleum
      • Could reduce trade deficits if country imports a significant amount of petroleum
    • A carbon permit system could increase the production of ethanol fuel
  • Problems
    • Vehicles can only use up to 15% ethanol by volume
      • Flexible fuel vehicles can use up to 85% by volume
      • So gasoline is still needed
    • Contains lower energy than gasoline
      • Ethanol contain 66% less energy by volume
    • Dissolves some rubber seals and gaskets in the fuel system and engine
    • Ethanol-gasoline blends separate in the presence of water
      • Cannot be re-blended until all the water is gone
      • Fuel tanks tend to accumulate moisture from humidity, especially during system
    • Ethanol-gasoline blends dissolves the nasty stuff in gasoline, like benzene, toluene, etc.
      • Ethanol seeps out of pipelines at a gas station, contaminating the soil.
        • Contamination areas are wider than gasoline leaks that contain no ethanol
  • Note
    • Industry could use butanol
      • A larger chain alcohol molecule
    • Has better fuel properties
      • Engines can burn any percentage of gasoline-butanol blends
      • Water and moisture is not a problem
      • Has 85% the energy as gasoline by volume
    • Uses a different microorganism, so all the capital for ethanol could be used
    • Problem - has a much lower yield

3. Biodiesel - substitute for diesel fuel

  • United States - take oil, lard, tallow, and yellow grease and convert them into a substance that resembles diesel fuel
  • Oil crops - main sources are corn and soybeans
    • Oil is extracted from the seeds
      • The residues contain high levels of protein that can be used in animal feeds
      • Residues are devoid of oil
    • Opportunity costs
      • Biodiesel industry competes with food for humans and animal feed
      • These commodities are exported
        • Lower exports worsen a trade deficit
  • Lard and tallow - products from the meat industry
    • As cattle, pigs, etc are processed into meat, tallow is produced as a byproduct
    • Opportunity cost - usually this oil is mixed in with animal feeds to increase fat content
    • Problem - a limited source, because tallow is a byproduct of the meat market
      • A derived demand - people eating meat indirectly produce tallow as a byproduct
  • Yellow grease - used cooking oil from restaurants and fast food places
    • Limited source for biodiesel
      • Derived demand - people eat out and yellow grease is created as a byproduct
      • Yellow grease is a byproduct of the restaurant industry
  • Benefits
    • Can be blended in any ratio with diesel fuel
    • Lubricates engine parts, possibly extending engine life
    • Recycles carbon dioxide from the atmosphere
      • Could slow down the buildup of greenhouse gases
    • Could boost farmers' incomes
      • Higher prices for crops
    • Biodiesel is not as flammable as diesel fuel
  • Problems
    • Biodiesel from vegetable oils freeze solid around 0 degrees Celsius
      • Biodiesel from tallow and lard have much higher freezing points
      • Biodiesel cannot be used in winters where temperatures dip below freezing
    • Vegetable oils are expensive

4. Electric cars - uses alternatives other than gasoline and diesel fuels

  • Cars use electric motors and batteries
    • Or use hybrid engines
      • Gasoline engine for driving at high speeds or acceleration
      • Use electric motor to maintain speed
      • Gasoline engine recharges batteries as car idles
      • It doubles the distance that once can drive on a tank of gas
  • Benefits
    • Reduces pollution in a city
      • However, requires more electricity
      • Most electricity is generated by coal power plants
  • Problems
    • Have to upgrade the electricity transmission grid
      • Very expensive capital improvement
    • Batteries wear out after five years
      • Batteries use strong acids or akalines
      • Presents disposal problems
    • Has short driving distances as batteries charge are used up
      • Except hybrid

Substitutes for Electricity Production

 

1. Hydroelectric power - use moving water like rivers to turn generators

  • Most common renewable energy source in the world
    • Used by ancient man
      • Grind grains into flour, cut lumber, textile machines, dock cranes, irrigation, etc.
  • Used for 20% of world electricity production
    • Three Gorges Dam in China is the largest hydroelectric station in the world
    • Pay for itself within 3 to 8 years
  • Benefits
    1. Produces very little greenhouse gases
      • Remember - greenhouse gases are released when producing and pouring concrete
      • Produces the lowest greenhouse gases
      • Mitigate greenhouse gases - if a hydroelectric plant replaces a coal plant, then it lowers greenhouse gases
    2. Has long capital life
      • 50 to 100 years
    3. Uses no input fuel
    4. Automated - little labor costs
    5. Not too expensive to build
    6. Can vary output
      • Easy to reduce power when people are using little electricity
    7. Creates lakes
      • People can enjoy the lake, like swim, fish, water ski, etc.
    8. Support industries
      • Creates a cheap source of electricity
      • Aluminum industry needs electricity to produce aluminum
  • Problems
    • Limited geographical areas for dam construction
    • Dam failure - dam breaks
      • Quickly floods a city further down stream
        • Banqiao Dam failure in Southern China
          • 171,000 deaths
        • Vajont Dam in Italy in 1963
          • Almost 2000 people died
    • Legal problems for the United States
      • Impacts wildlife like fish, turtles, etc.
      • Turbine blades cut up the fish
      • Harms salmon - salmon return to the stream to create new offspring
        • Dams construct fish ladders
Country Energy Production Installed Capacity Percent Total Electricity
  TWH Giga-Watts 100%
China 585.2 171.52 17.18
Canada 369.5 88.974 61.12
Brazil 363.8 69.08 85.56
United States 250.6 79.511 5.74
Russia 167 45 17.64

2. Geothermal - uses heat from the earth to turn water into steam that turns the turbines for the generators.

  • Used by ancient man
    • For heat and steam baths.
  • Used for 0.3% of world electricity production
    • A total of 10 gigawatts of capacity is installed
  • Used also for heat
    • Water can be pumped directly into radiators
    • Reykjavík, Iceland
      • Located near hot springs
      • Use geothermal heat to heat buildings
      • Then water leaving buildings heat sidewalks and roads, melting the ice
  • Benefits
    • Emits very little greenhouse gases
      • Carbon dioxide and methane gases are emitted from the ground
        • So are sulfur oxide emissions
      • Mitigates greenhouse gases - if geothermal plant replaces a coal plant, then greenhouse gases emissions are lower
    • Occupies very little space
      • Pipes are put directly into the ground
    • Sustainable - could produce electricity for a long time
      • Some hot springs, etc. have shown cooling
        • Extracting too much heat
          • Heat is generated from gravitational forces and radioactive decay deep in the earth
        • Water source is cut off
  • Problems
    • Very few areas can support geothermal plants
      • Located near places where tectonic plates meet
      • Places with earthquakes
      • A plant was in Switzerland was shut down after it triggered earthquakes
    • Very expensive to drill into the earth to lay the pipes
      • Nevada - $10 million to drill, with a 20% failure rate.
  • Note - heat pumps have greater application
    • Only requires slightly warm temperatures
    • Pipes are buried around a house or building
    • Water is pumped through the pipes collecting heat energy and then taken to a heat exchanger
    • Heat exchanger connects to a building’s heating system
    • Helps lower heating bills

3. Wind Power - use wind to turn large blades that in turn rotate a generator

  • Ancient form of energy
    • Man has used wind to push sailboats
    • Used windmills since 7 AD to grind grains into flour or pump water
  • Wind supplies about 1.5% of the electricity energy in the world
    • 121 gigawatts of capacity are installed
  • Feed-in tariffs - a country guarantees a price for each watt of electricity a wind farm generates
    • Most costs are capital, thus producers know what price they are getting.
    • Canada and Germany
    • Germany guarantees a price of 8.4¢/kWh for wind
  • Benefits
    • Relatively cheap - approximately 5-8 cents/kWh
    • Has low capital costs for turbines, generators, and towers.
      • Could have higher costs if located too far away from the grid
    • Produces no greenhouse gases when operating
      • Does produce greenhouse gases when equipment is manufactured
    • Could mitigate the buildup of greenhouse gases
      • If wind power replaces a coal electric plant, then greenhouse gas emissions are lower.
    • Wind generators can be small
      • A farmer can put a couple on his property to provide electricity for his farm
      • Rural communities can also use wind generators
        • Connecting or upgrading the grid may cost too much
  • Problems
    • Limitations where windmills can be placed
      • Are located in areas with lots of wind
    • If a wind stops blowing, then the wind farm stops generating electricity
      • Coal generators have to be operating at low capacity
      • Then turn them on all the way up to make up for the loss of power
        • Otherwise, if the supply of electricity is not enough for demand, then the system shuts down.
        • i.e. a blackout
    • Variability of wind means wind could never be a dominant energy source
    • Windmills are not attractive
      • Be located outside in the country and rural areas
    • Blades used to chop birds in half
      • Some generators run at lower speeds so birds avoid them
    2005 2008
Rank Country Wind Power % of Total Wind Power % of Total
1 United States 17.8 0.40% 52 1.30%
2 Germany 27.2 5.10% 38.5 6.6%
3 Spain 20.7 7.90% 31.4 11.10%
4 People's Republic of China 1.9 0.10% 12.8 0.40%
5 India 6.3 0.90% 14.7 1.9%
6 Italy 2.3 0.70% 4.9 1.40%
7 France 0.9 0.20% 5.6 1.10%
8 United Kingdom 2.8 0.70% 5.9 1.5%
9 Denmark 6.6 18.50% 6.9 19.10%
10 Portugal 1.7 3.60% 5.7 11.30%

Note - The 2008 numbers for Germany, India, and United Kingdom are actually 2007.

4. Solar Energy - use energy from the sun to generate electricity

  • Ancient Greek legend - Archimedes used polished shields to concentrate sunlight on the invading Roman fleet and repel them from Syracuse.
  • Solar photovoltaic - silicon wafers that convert sun radiation into electricity
    • Can use mirrors and lenses to focus a sun's rays
      • Sun's energy heats water and then steam drives a turbine for a generator
      • Useful for modular locations (e.g. remote lighting, signs, etc.), but not for mainstream use.
  • Germany and Spain are the biggest investors in solar energy
    • Both use feed-in tariffs to guarantee prices to producers
      • Germany guarantees a price of 55¢/kWh for solar
    • France, Italy, South Korea, and United States are catching up
  • Benefits
    • Reduces greenhouse gas emissions
      • No emissions after solar panels are installed
      • Releases a lot of emissions during manufacturing
        • Silicon is heated up to form a crystal
    • Homeowners can place solar panels on roof
      • Supplement's a household's electricity
      • Install reversible power meters
        • If more energy is generated from the solar panels than what is used by the household, the power is supplied back through the line
        • The meter runs backward
    • Solar cells and wind power are complementary
      • Sunny days tend to have little wind
      • Cloudy days tend to be windy
    • Can power electric signs and meters in sunny locations
      • A battery supplies power at night or on cloudy days
      • When the sun is shining, the batteries are re-charged
    • Power sources for satellites and space crafts sent into outer space
      • United States and Soviet Union
  • Problems
    • Are very expensive
    • Solar photovoltaics have lower energy efficiency
      • Only 6% of sunlight is converted to electricity
      • Greatly increasing this inefficiency could make them more attractive
    • Sunlight is intermittent
      • Power is greatly reduced on cloudy days
      • No power is supplied at night time

5. Nuclear energy

  • Use a radioactive reaction as a heat source
    • Heat water, sodium, etc and send it to an energy exchanger
      • Minimize the transfer of radioactive substances
    • Usually water is heated at the exchange into steam
    • Steam turns the turbines
    • The turbines turn the generators
      • Nuclear power plants are usually located near a water source like a lake
      • Lake cools the water
      • Temperature differences allow the nuclear power plant to create electricity
  • Nuclear energy supplied 15% of the world's electricity in 2005
    • 439 nuclear reactors in the world
    • 31 countries use nuclear power
    • 150 navel vessels are powered by nuclear power
      • U.S. Navy - submarines and aircraft carriers
      • Soviet-Russian Navy
  • Three largest producers of nuclear power
    • United States - nuclear power supplies 19% of the electricity
    • France - nuclear power supplies 78% of the electricity
      • France has no petroleum resources
  • Japan - nuclear power supplies 30% of electricity
    • Japan has few natural resources
  • Construction costs
    • United States
      • Construction costs have skyrocketed
      • New regulations and lawsuits delay projects
      • New nuclear plant could cost from $6 to $10 billion in the United States.
        • Costs 30% more over the life of fossil fuel plant
      • Fear of nuclear accidents
        • 1986 Chernobyl disaster in Ukraine
        • 1979 accident at Three Mile Island , Pennsylvania
          • Radiation was released.
  • Pakistan, Japan, China and India are active in developing more nuclear reactors
    • Their economies may grow fast, fueling the need for more energy
    • Benefits
      • Nuclear power plants emit very little greenhouse gases
    • Problems
      • Nuclear accidents
      • Radioactive waste
        • United States has an estimated 50 thousand metric tons of wastes
        • After 10,000 years, this waste would no longer pose a health risk to humans
  • Recycling
    • France and Britain many other countries recycle the spent uranium rods
    • However, they extract plutonium which could also be used in nuclear weapons
      • Thought it required a breeder reactor???
    • Requires a breeder reactor
      • Russia is the only country with one
      • Japan, India, and China plan to build breeder reactors
  • Backstop Technology
    • May not be a backstop technology
      • Legal and regulatory barriers that prevent construction of nuclear power plants
      • Environmental hazard of storing nuclear waste for thousands of years
      • Costs 30% more over the life of fossil fuel plant
    • If developed countries developed a carbon permit system for greenhouse gas emissions
      • Coal electric power plants become expensive
      • Nuclear power becomes more attractive

6. Biomass - burn crop and wood residues with coal to generate electricity

  • The feedstocks are the same ones as for ethanol
    • Energy crops - burn the fast growing perennials with coal
      • Switchgrass, willow, and hybrid poplar
    • Crops residues and manure
    • Wood residues from saw mills - places where trees are cut into products
  • Benefits
    • Has cleaner emissions
    • Recycles carbon from atmosphere - reduces greenhouse emissions
  • Problems
    • Crops residues, energy crops, and wood residues are bulky and light weight
      • Costs could rise exponentially the further the distance to haul the feedstocks to the electric power plant
      • Power plants would have to be located near their sources
    • Requires upgrades in equipment for the power plant

Carbon Sequestration

 

1. Carbon sequestration - a process to remove carbon out of the air and store it

  • Process can be biological, chemical, or physical process
  • Large variety of technologies - only the most common are discussed
  • Mitigates the accumulation of greenhouse gases in atmosphere
    • On a large scale, it could lower greenhouse gases
  • Also called sinks

2. Change tillage technology

  • Standard farming practice is to till the soil by breaking it up and turning the soil over
    • Carbon in the soil is exposed to oxygen and reacts to it
    • Reaction is small, but over millions of acres, it adds up
  • No till - machine bores a small hole into soil and places seed
  • Problem - soil has a limit to how much carbon can be stored
  • Change fertilizer applications can reduce greenhouse gas emission
    • Nitrogen increases emissions from Nitrogen dioxide (N2O)

3. Re-Forestation - plant more trees

  • Have to ensure trees thrive and grow
    • If a tree rots or is burned, then the carbon is released back into the atmosphere
  • If trees are harvested, then carbon is still stored in roots and lumber

4. Fertilization of the oceans

  • Controversial method - unsure of the impact on ocean life
  • Dump iron and fertilizers into the ocean
  • Encourages plankton growth
    • Plankton - simple plant life that float in the water
    • Can see plankton blooms from outer space
  • Could potentially remove large amounts of carbon dioxide out of the ocean

5. Pyrolysis of wastes - Burn wastes slowly without oxygen

  • Could use special ovens to breaks down wastes into carbon which can be mixed into soils
    • Could be done on a large scale with wastes that are heading to a landfill
    • Could increase greenhouse gas emissions, because the heat source creates carbon dioxide
  • Terra Preta - created by humans between 450 BC and AD 950 in the Amazon
    • Terra Preta - means black earth
    • Contains high amounts of carbon
    • Carbon encourages microbial activity
      • Microbes increase carbon activity
      • carbon content could increase over time
    • Soil attracts earth worms
    • Carbon helps retain the nutrients in the soil
    • Soils are very healthy

6. Capture the carbon dioxide

  • Emissions from a coal power plant is pumped into an old mine shaft, salt dome, deep water in a bay, etc.
  • Deep water formations - contain calcium and magnesium deposits
    • Carbon dioxide reacts with salt and minerals in the water to form carbonates
    • Carbonates are stable
    • Limestone is calcium carbonate
  • Carbon dioxide is also injected into petroleum wells to increase output
  • Note
    • Burial wastes in landfills or dumping it into the seas is another way to capture the carbon
      • As long as methane and carbon dioxide does not reach the atmosphere
 

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